CA2777203C - Blowout preventer and rams - Google Patents

Abstract

A ram type blowout preventer includes a seal on each ram, extending across the front face, rearwardly and then over the top portion or the bottom portion of the ram. Each ram forms a leading edge portion above or below the front face seal, so that, as opposing rams move into the extended, sealing position, the leading edge portions of the rams abut and press against each other, imparting a generally vertical movement to the rams to bring the seals on the front faces into sealing engagement with each other and to energize the seals extending over the top or bottom portions against the ram bores. The front face of each ram may include an inclined portion which is inclined toward the central bore. Rope packing seals may be provided on the rams, but with a vertical offset at the front faces of the rams such that the rope packing seals on opposing front faces seal against each other, but with the vertical offset.

Description

2 BACKGROUND

3 Wellhead blowout preventers are used in oil wellhead assemblies to seal against

4 a central bore. In a pumping production wellhead, the blow out preventer (BOP) may be configured to seal against a polish rod or a tubular member if present. The rams of 6 a BOP may operate in different ways in closing off a well, or multiple BOPS may be 7 used in a wellhead stack to provide different functions. In a production pumping well, 8 opposing polish rod BOP rams accommodate and seal around a polish rod extending 9 generally vertically through the wellhead. Blind BOP rams seal against each other across the central bore when no polish rod is in place.
11 A typical prior art BOP for a production wellhead is disclosed in U.S.
Patent No.
12 5,765,813 to Lam et al., issued Jun. 16, 1998, owned by Stream-Flo Industries Ltd., the 13 assignee of this patent application. This type of BOP is commonly used in connection 14 with pumping production wells. With such wells, a sucker rod string is reciprocated or rotated to drive a downhole pump, which lifts the produced fluid to the surface through a 16 tubing string. The BOP is equipped with a pair of opposing polish rod rams which can 17 be advanced horizontally to seal around the vertical polish rod portion of the rod string 18 to prevent the upward escape of fluid. Alternatively, if the rod string is out of the well, 19 the inner or front ends of the rams can be pressed together to cause closure of the wellhead assembly fluid passageway.
21 More particularly, a typical pumping production BOP includes a cross-shaped 22 housing forming a central, generally vertical bore and a pair of coaxial, horizontal ram 23 bores intersecting the central bore from each side. The BOP is commonly positioned in 1 the wellhead assembly between the tubing head and flow tee. In this configuration, the 2 central bore of the BOP forms part of the wellhead assembly fluid passageway. Within 3 the BOP, a pair of rams is positioned in the horizontal ram bores.
Actuator 4 mechanisms, which generally include rams screw powered by mechanical, electrical, pneumatic or hydraulic actuators, are provided at the outer ends of the ram bores, for 6 extending or retracting the rams into or out of the central bore, in order to close or open 7 the central well bore. Each BOP ram comprises a generally cylindrical body, although 8 other shaped ram bodies are known (ex. oval, rectangular or square in cross section).
9 The ram generally comprises a steel core, preferably having an outer full bore diameter portion (or rear portion) and a reduced diameter inner portion (or front portion). The 11 ram core inner portion is covered with and bonded to a layer of an elastomeric material, 12 typically a nitrile rubber. The ram bores, typically cylindrical, extend into the central 13 bore and the bore surfaces combine at their intersection to form sealing areas. When 14 the rams move into the central bore, the rubber surfaces of their inner portions seal against the sealing surfaces.
16 The rubber-coated inner or front face of each ram is typically formed to provide a 17 semi-circular, vertically directed groove, also termed vertical radial groove. When the 18 polish rod of the rod string is present in the central bore, opposing ram ends encircle 19 and press against the polish rod to form a seal of the central bore.
When the polish rod is not present the ram ends compress together to form a solid block. In both cases, the 21 circumferential seals of the ram side surfaces, with the sealing areas and the end face 22 seals, combine to close the central bore and contain pressurized fluids.
23 U.S. Patent No. 7,673,674, issued March 9, 2010 to Tony M. Lam, and assigned 24 to Stream-Flo Industries Ltd., the assignee for this patent application, describes a BOP
ram and/or polish rod claim in which the vertically directed groove at the front face of 26 the ram is shaped as a V-groove to accommodate a portion of the circumference of the 27 polish rod. U.S. Patent No. 7,552,765 to Tony M. Lam, issued June 30, 2009, and 28 assigned to Stream-Flo Industries Ltd., describes a BOP in which one of the rams is 1 formed with an extended central bore sealing section behind the front sealing end of the 2 ram, such that the extended central bore sealing section can be extended across the 3 central bore to seal the central bore when the polish rod is not present.
4 In a production BOP, pressure acting from below on the closed BOP rams may extrude the side rubber upwardly so that the circumferential seal with the sealing areas 6 is lost. As well, the end rubber bonded to the vertical end faces (front faces) of the ram 7 cores may tear loose from the core when high pressure is exerted from below. In 8 severe conditions, such as injecting chemicals to close off a well, the rubber degrades 9 quickly, causing the seals to fail. A large number of BOP ram designs exist to address problems of extrusion, tearing or degradation of the BOP ram seals.
11 Canadian Patent Application No. 2,260,655, published Aug. 2, 2000 naming 12 Tony M. Lam and Keith D. Farquharson as inventors and Stream-Flo Industries Ltd. as 13 assignee, describes a ram type BOP for high temperature applications.
The BOP
14 incorporates a generally L-shaped seal element formed of a graphite or asbestos seal material, which is sandwiched between a bottom L-shaped steel retainer plate and a 16 semi-cylindrically shaped steel top retainer plate. This design of BOP
ram is well suited 17 for brittle seal materials such as graphite and asbestos when higher temperatures are 18 encountered.
19 Other ram type BOP devices exist which use graphite or asbestos type seals or seal inserts. However, graphite and asbestos type sealing materials typically include 21 polymeric bonding materials which have lower temperature limits than graphite or 22 asbestos, so the seals are prone to failure at very high temperatures, such as 23 temperatures above 600 F. Today, high temperature wellhead applications such as 24 steam injection may require the wellhead equipment to accommodate temperatures above 600 F. Also, the use of asbestos seal materials is being phased out in industry 26 due to harmful effects of asbestos fibres in handling, manufacture and in use.

1 Thermoplastic materials having superior chemical resistance are available, but 2 have different compressibility and elastic properties than elastomeric sealing materials 3 such as nitrile rubbers. Thus, BOP devices are not generally amenable to simple 4 substitution of thermoplastics for the rubber sealing components. U.S.
Patent No.
7,137,610, issued to Lam on November 22, 2006, and assigned to Stream-Flo 6 Industries Inc., describes a production BOP and BOP rams incorporating thermoplastic 7 seals at the front of the rams to seal against the polish rod. However, even 8 thermoplastic materials have temperature limits below the temperatures encountered 9 for steam injection wellheads.
In spite of the above advances in BOP ram seals, there is still a need for BOP
11 devices capable of withstanding very high or very low temperature environments. For 12 instance, in wellheads through which steam is injected to enhance recovery in depleted 13 wells or for heavy oil wells, temperatures in excess of 650 F can be reached. These 14 temperatures far exceed the limits of nitrile rubber seals, elastomeric seal materials, and thermoplastic seal materials. As above, BOP devices adapted to carry graphite or 16 asbestos seals are also subject to failure at such extreme temperatures as polymeric 17 bonding materials in the seals begin to break down. As well, at very low temperatures, 18 conventional BOP sealing materials become very hard or brittle, interfering with the 19 ability to make reliable seals.
There is a still a need for a ram type BOP which can reliably seal against a polish 21 rod and/or the central bore of a wellhead in very high temperature and very low 22 temperature applications.

24 In one broad aspect, there is provided a ram type blowout preventer such as may be used in a pumping production well. The blowout preventer includes:
26 a) a housing forming a central bore extending generally vertically through the 1 housing, and a pair of ram bores extending radially outwardly in opposite directions 2 through the housing and intersecting the central bore;
3 b) a steel bodied ram positioned in each of the pair of ram bores to provide 4 opposing rams, the ram having a front end portion, a rear end portion, a top portion and a bottom portion and being adapted for sliding movement in the ram bore between an 6 extended position, with the front end portion extending across the central bore and the 7 rear end portion within the ram bore, and a retracted position within the ram bore, the 8 ram being configured with a front face to seal against the front face of the opposing ram 9 and to accommodate and seal against a tubular member or rod, if present in the central bore;
11 c) a ram actuating mechanism connected to the rear end portion of the ram for 12 extending and retracting the ram between the extended and retracted positions;
13 d) a seal on the ram, the seal extending across the front face, then rearwardly, and 14 then either upwardly over the top portion or downwardly over the bottom portion, at a position rearwardly of the front end portion; and 16 e) the front face of the ram forming a leading edge portion located either above or 17 below the seal so that, as the opposing rams are moved into the extended position, the 18 leading edge portions of the opposing rams abut and press against each other, 19 imparting a generally vertical movement to the opposing rams to bring the seals on the front faces into sealing engagement with each other and to energize the seals 21 extending over the top portion or the bottom portion against the ram bores;
22 f) whereby, in the extended position, the seals on the opposing rams seal against 23 each other, against the tubular member or rod if present, and also seal the central bore.
24 In some embodiments, the front face of the ram includes an inclined portion such that a plane through the inclined portion is inclined toward the central bore, and the 26 inclined portion is adapted to be brought into contact with the inclined portion on the 27 opposing ram by the generally vertical movement imparted to the opposing rams. In 28 this embodiment, the seal may be located on the inclined portion of the ram such the 29 seals on the front faces of the opposing rams seal against each other as the inclined

5 1 portions of the rams contact each other.
2 In some embodiments, the ram actuating mechanism includes a ram screw 3 connected to the rear end portion of the ram at a point either above or below a center 4 axis of the ram bore to facilitate imparting the generally vertical movement to the ram in the extended position.

6 In some embodiments, the front face of the ram may be formed with a cut away

7 portion located above or below the seal to allow the ram to flex in the ram bore. In

8 some embodiments the cut away portion is a horizontal slot extending across the front

9 face and rearwardly in the ram.
In some embodiments the front face of the ram may form the inclined portion in a 11 manner such that a plane through the front face is inclined top to bottom toward the 12 central bore, and such that the leading edge portion is formed adjacent the top portion 13 of the ram.
14 In other embodiments, the leading edge portion on the front face of the ram is a flattened planar portion formed adjacent either the top portion or the bottom portion of 16 the ram, such that a plane through the flattened portion is generally vertical.
17 The seal of the blowout preventer may be formed as an elastomeric, a 18 thermoplastic seal, or a rope packing seal. For a rope packing seal, the seal may be 19 formed from a length or a loop of a rope packing material which can accommodate very high and/or very low temperatures. The seal may be formed as a primary rope packing 21 seal formed from a first length or loop of rope packing extending across the front face, 22 then rearwardly, and then upwardly over the top portion of the ram at a position 23 rearwardly of the front end portion of the ram, with the primary rope packing seal being 24 held in, so as to protrude radially outwardly from, a continuous first groove formed in the ram.

1 In some embodiments, the blowout preventer includes a primary rope packing 2 seal which extends across the front face of the ram with a vertical offset relative to the 3 primary rope packing seal on the front face of the opposing ram, such that in the 4 extended position, the primary rope packing seals on the opposing rams seal against each other but with the vertical offset.
6 In some embodiments, the blowout preventer may include a secondary rope 7 packing seal formed on the ram from a second length or loop of rope packing extending 8 across the front face, and being spaced from the primary rope packing seal. The 9 secondary rope packing seal is held in, so as to protrude radially outwardly from, a second groove formed in the ram. The secondary rope packing seal may extend 11 across the front face of the ram with a vertical offset relative to the secondary rope 12 packing seal on the front face of the opposing ram, such that in the extended position, 13 the secondary rope packing seals on the opposing rams seal against each other but 14 with the vertical offset.
In another broad aspect, there is provided a ram type blowout preventer which 16 includes:
17 a) a housing forming a central bore extending generally vertically through the 18 housing, and a pair of ram bores extending radially outwardly in opposite directions 19 through the housing and intersecting the central bore;
b) a steel bodied, full bore ram positioned in each of the pair of ram bores to 21 provide opposing rams, the ram having a front end portion, a rear end portion, a top 22 portion and a bottom portion and being adapted for sliding movement in the ram bore 23 between an extended position, with the front end portion extending across the central 24 bore and the rear end portion within the ram bore, and a retracted position within the ram bore, the ram being configured with a front face to seal against the front face of the 26 opposing ram and to accommodate and seal against tubular member or rod, if present 27 in the central bore;
28 c) an actuating mechanism connected to the rear end portion of the ram for 1 extending and retracting the ram between the extended and retracted positions, 2 d) each ram comprising:
3 i. a body component forming the bottom portion of the ram, the body 4 component having a front portion, a rear portion, a front end and a rear end;
6 ii. a seal component forming the top portion of the ram and extending 7 rearwardly of the front end portion of the ram, the seal component having 8 a front portion, a rear portion, a front end, a rear end, and a front face;
9 iii. the body component having a cut-out in its front portion to provide a seal support surface to support the seal component, the seal support 11 surface being inclined front to rear such the seal component rides 12 upwardly and rearwardly on the seal support surface;
13 iv. the seal component having an inner surface which generally 14 conforms to the seal support surface of the body component;
v. the body component and seal component combining, in an 16 assembled form, to form the full bore ram, which when out of the 17 extended position has the front end of the seal component forming a 18 leading edge portion which protrudes a horizontal distance beyond the 19 front end of the body component; and vi. connectors for connecting the seal component and the body 21 component while allowing the seal component, in the extended position, 22 to be pressed against the seal support surface of the body component 23 and to ride upwardly and rearwardly on the seal support surface;
and 24 e) a primary rope packing seal formed on the seal component of the ram from a first length or loop of rope packing, the primary rope packing seal extending across the 26 front face of the seal component, rearwardly, and then upwardly over the top portion of 27 the ram at a position rearwardly of the front end portion of the ram, the primary rope 28 packing seal being held in, so as to protrude radially outwardly from, a continuous first 29 groove formed in the seal component;
f) such that, in the extended position, the primary rope packing seals on the 1 opposing rams seal against each other, against the tubular member or rod if present, 2 and also seal the central bore.
3 The front face of the BOP ram may be formed with a vertical groove to 4 accommodate a polish rod or other tubular member. In some embodiments the vertical groove is a radial groove. In other embodiments the vertical groove is a V-groove with 6 the seal(s) extending across a raised radial backing section formed in the V-groove to 7 seal to the tubular member or rod. In yet other embodiments the front face of the BOP
8 ram body is formed as a blind ram to seal against an opposing ram without the polish 9 rod.
The blowout preventer of any of these embodiments may be configured as a 11 wellhead assembly which may include the BOP alone, or in a stack with one or more 12 other wellhead components. The blowout preventer of any of these embodiments may 13 alternatively be included in a wellhead assembly provided as an integral composite 14 assembly with one or more other wellhead components which might include, in any sequence, adaptors, control valves, additional BOPS, check valves, a flow tee, and a 16 polish rod clamp. The wellhead assembly of any of these embodiments includes top 17 and bottom connectors for connecting to wellhead components located above and 18 below. Such connectors may be of any type, as is known in the industry, including for 19 example studded connectors, flange connections, welded connections, clamp and threaded connections. Also provided are the BOP rams configured as set out for any of 21 the embodiments described herein.
22 The rams and ram bores may be of any shape or configuration as is known in 23 the BOP industry. While the figures show the rams and ram bores as being cylindrical 24 in cross-section, they may be alternatively shaped, such as oval in cross section. As used herein, the term "cylindrical" is understood to include rams and ram bores which 26 are generally circular or oval in cross section.

1 It should be understood that the terms "front", "rear", "upper", "lower", "inner", 2 "outer", "top" and "bottom", as used herein and in the claims with reference to the 3 wellhead components and the BOP ram or its parts, refer to the component or ram as it 4 is designed to be positioned in one of the horizontal ram bores, for longitudinal movement forwardly into the central bore or rearwardly in the horizontal ram bores. By 6 "front", as used herein, is meant the portion or end of the ram or its parts at the central 7 bore, or that is facing the central bore. By "rear" is meant the portion or end of the ram 8 or its parts opposite the front. By "outer" is meant the outer circumferential portion of 9 the ram or its parts. The term "central" in reference to the "central bore" is meant to include a generally vertical well bore which may be somewhat off-center in the wellhead 11 assembly, or somewhat inclined relative to vertical, such as occurs in horizontal or 12 inclined oil/gas wells. Thus the term "generally vertical", or "vertical" is meant to include 13 well bores that are inclined relative to vertical, and wellhead components configured to 14 accommodate such configurations. Similarly, the term "horizontal ram bore" is meant to include generally horizontal ram bores which intersect the central bore at angles 16 generally perpendicular to the longitudinal axis of the central bore.

18 As used herein and in the claims, a reference to "a connection,"
"connected" or 19 "connect(s)" is a reference to a sealed pressure-containing connection unless the context otherwise requires.
21 As used herein, "comprising" is synonymous with "including,"
"containing," or 22 "characterized by," and is inclusive or open-ended and does not exclude additional, 23 unrecited elements or method steps. The invention illustratively described herein 24 suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.
26 The use of the indefinite article "a" in the claims before an element means that 27 one of the elements is specified, but does not specifically exclude others of the 28 elements being present, unless the context clearly requires that there be one and only 1 one of the elements.

3 Figure 1 is a side view of one embodiment of a production blowout preventer 4 (BOP) showing the housing, end plugs and ram screws in section, and showing both of the BOP rams in an extended sealing position against a polish rod.
6 Figure 2 is a perspective view of one of the BOP rams from Figure 1, formed with 7 a radial vertical groove at its front face to accommodate a polish rod, and showing a 8 primary rope packing seal, a secondary rope packing seal spaced from the primary 9 rope packing seal, and a circumferential rope packing seal formed rearwardly of the primary and secondary rope packing seals. Each rope packing for these seals is held 11 in continuous grooves formed in the ram.
12 Figure 3 is a side view of the BOP ram of Figure 2.
13 Figure 4 is side sectional view along line 4-4 of Figure 6, partially cut away, 14 showing the overlapping ends of the primary rope packing seal at the top portion of the ram, and also showing a central T-slot at the rear of the ram to lock onto the ends of a 16 ram screw used to extend and retract the ram.
17 Figure 5 is a partial front view of the ram of Figure 2 showing the primary and 18 secondary rope packing seals extending across the vertical radial groove.
19 Figure 6 is a top view of the ram of Figure 2, showing the primary rope packing seal overlapping ends at the top portion of the ram.
21 Figure 7 is a perspective view of the ram of Figure 2, with the primary and 22 secondary rope packing seals removed, showing the dove-tail shaped grooves to retain 1 the lengths of rope packings.
2 Figure 8 is a perspective view of a further embodiment of a BOP ram having a 3 blind front face for sealing across the central bore when a polish rod is not present, and 4 incorporating primary and secondary rope packing seals.
Figure 9 is a perspective view of a further embodiment of a BOP ram having a V-6 shaped vertical groove at its front face, and including the primary and secondary rope 7 packing seals extending across a raised radial backing section formed in the V-grove to 8 seal the polish rod.
9 Figure 10 is a perspective view of a further embodiment of a BOP ram having an alternate spacing arrangement of the primary and secondary rope packing seals.
11 Figure 11 is a top view of a further embodiment of a BOP ram, showing joined 12 abutting ends of the primary rope packing seal and the circumferential rope packing 13 seal, with the joined abutting ends both being located at the top portion of the ram.
14 Figure 12 is a top view of a further embodiment of a BOP ram, showing joined abutting ends of the primary rope packing seal, and overlapping ends of the 16 circumferential rope packing seal, with the joined abutting ends and the overlapping 17 ends being located at the top portion of the ram.
18 Figure 13 is a top view of a further embodiment of a BOP ram, showing joined 19 abutting ends of the primary rope packing seal at the top portion of the ram, and joined abutting ends of the circumferential rope packing seal located at the bottom portion of 21 the ram.
22 Figure 14 is a side view of another embodiment of a production blowout 23 preventer (BOP) with the housing, end plugs and ram screws in section, and showing 1 the opposing BOP rams being moved into an extended position with the leading edge 2 portions on the ram front faces adjacent the top portions of the rams making initial 3 contact with each other, and also showing the vertical offset of the rope packing seals 4 at the front faces of the opposing rams, the horizontal slot in the rams below the seals, the inclined portions on the front faces of the rams, and the off center connection of the 6 ram screws at the rear of the rams.
7 Figure 15 is a side view of the left side BOP ram of Figure 14 showing the front 8 face of the ram being formed with an inclined portion which is inclined top to bottom 9 toward the central bore, and showing a primary rope packing seal extending rearwardly along the side of the ram and over the top portion of the ram, a secondary rope packing 11 seal spaced from the primary rope packing seal and extending rearwardly along the 12 side of the ram to meet the primary rope packing seal.
13 Figure 16 is a side view of another embodiment of a BOP ram similar to the ram 14 of Figure 15, but showing the leading edge portion adjacent the top portion of the ram formed as a flattened planar section such that a plane extending therethrough is 16 generally vertical, whereby the flattened planar portions of opposing rams meet in the 17 generally vertical plane at the initial point of contact with each other.
18 Figure 17 is a front perspective view of the BOP ram of Figure 17 with the 19 primary and secondary rope packing seals removed to show a continuous first groove to retain a first length of rope packing and having a widened portion at the top portion of 21 the ram to accommodate overlapping ends of the first length of rope packing, a second 22 groove for a second length of rope packing extending rearwardly to meet the 23 continuous first groove, and a radial vertical groove formed at the front face of the ram 24 to accommodate a polish rod.
Figure 18 is a front perspective view of the BOP ram of Figure 18 with the 26 primary and secondary rope packing seals held in the grooves so as to protrude radially 1 outwardly from the grooves.
2 Figure 19 is a side sectional view taken along line 1 9-1 9 of Figure 18, partially 3 cut away, at the rear end portion of the BOP ram, to show the primary rope packing 4 seal at the top portion of the ram for sealing against the ram bore, and to show the T-S slot at the rear end of the ram for the off center connection, below the center axis of the 6 ram bore, to the ram screw.
7 Figure 20 is a front perspective view of a BOP ram similar to the BOP
ram of 8 Figure 18, but showing a vertical groove which is V-shaped to accommodate at least a 9 portion of the circumference of the polish rod within the V-groove, and showing the primary and secondary rope packing seals extending across a raised radial backing 11 section formed in the V-groove to seal the polish rod.
12 Figure 21 is a front perspective view of a BOP ram similar to the BOP
ram of 13 Figure 18, but showing a front face formed as a blind ram such that the front faces of 14 opposing rams seal against each other in the extended position to seal the central bore.
Figure 22 is a front perspective view of a BOP ram similar to the ram of Figure 16 18, but showing the primary and secondary rope packing seals configured with the 17 alternate spacing arrangement as shown in Figure 10.
18 Figure 23 is a side view of an alternate embodiment of a production BOP ram 19 formed with a bottom body component and a top seal component, the components being connected and configured such that the seal component, in the extended 21 position, is pressed against an inclined seal support surface of the body component and 22 rides upwardly and rearwardly on the seal support surface. The BOP ram is shown to 23 include primary and secondary rope packing seals formed on the seal component.

2 Multiple embodiments of a production blowout preventer (BOP) and BOP
rams 3 adapted for a production pumping BOP are shown in the Figures, with like parts being 4 labeled with the same reference numerals. In Figures 1-13, the BOP rams are configured with generally parallel planar front faces, and provide primary rope packing 6 seals, and optionally secondary rope packing seals and circumferential rope packing 7 seals. In Figures 14-23, the BOP rams may be configured with a leading edge portion 8 at the front faces of the opposing rams to abut and press against each other in the 9 extended position so as to impart a generally vertical movement to the opposing rams.
Alternatively, or in addition, the BOP rams of Figures 14-23 may be configured such 11 that the seals across the front faces of the opposing rams have a vertical offset such 12 that the seals seal against each other, but with the vertical offset.
13 Having reference to Figure 1, a production blowout preventer (BOP) is shown 14 generally at 10, to include a cross-shaped, pressure-containing steel housing 11 forming a central bore 12, extending generally vertically through the housing 11, and a 16 pair of co-axial horizontal ram bores 14. The ram bores 14 are slightly larger in 17 diameter than the central bore 12, as is common in BOP devices. Top and bottom 18 flange connectors 15, 16 to wellhead components located above and below the BOP 10 19 are shown, although alternate top and bottom connectors such as threaded, welded, studded, or clamp connections may be used. The horizontal ram bores 14 intersect 21 with the central bore 12. The polish rod P is shown in place in the central bore 12. The 22 polish rod P is an example of a tubular member which may be present in the central 23 bore.
24 A pair of generally cylindrical BOP rams 18 are shown in Figure 1. Each of the rams 18 may be formed in multiple parts, but are generally cylindrically shaped when 26 assembled for close fitting relationship in, and optionally for sealing to, the ram bores 27 14. The rams 18 are generally formed as steel bodied rams. The rams 18 are locked 1 onto the ends of ram screws 20, which extend through end plugs or bonnets 22 at the 2 outer ends of the ram bores 14. The ram screws 20 can be turned to extend or retract 3 the rams 18 into or out of the central bore 12 with mechanical screw jacks (not shown).
4 The ram screw 20 is connected at the rear face 33 of the ram 18, typically in a T-slot 35 (see Figure 4), in a manner known in the art. Alternatively, the ram screws 20 can be 6 extended and retracted with hydraulic actuators (not shown), as known in the art. It 7 should be understood that the rams 18 may be alternately actuated, for instance by 8 pneumatic or electrical actuators. Actuators may be single or double acting, as known 9 in the art. Any of these mechanical screw jacks or alternate actuators thus illustrate actuators or ram actuating mechanisms for extending and retracting the rams 18 11 between their open position, in which the rams 18 are retracted from the central bore 12 12, and the closed, sealing position, in which the opposing rams 18 are extended to 13 seal around the polish rod P, and thus to seal the central bore from pressure below.
14 It should be understood that one of the rams, along with the ram bores, may be adapted to include and accommodate an extended central bore sealing section as 16 described in U.S. Patent 7,552,765.
17 It should be understood that the ram bores 14 and corresponding rams 18 are 18 not necessarily strictly cylindrical in shape. The rams and bores may take alternate 19 shapes, such as oval in cross section, as is known in the art.
A first embodiment of a ram 18 is shown in Figure 2. In Figure 1, this first 21 embodiment of a pair of rams 18 are shown in their fully extended, sealing position, with 22 opposing front faces 32 (see Figure 2) sealed against each other, against the polish rod 23 P, and against the central bore 12. The seal arrangement is one in which the rams 18 24 carry seals adapted to seal the central bore 12 against pressure from below. However, it should understood that the rams 18 may be rotated or configured in a different 26 manner. For example, a ram which is rotated 180 compared to Figure 1, will seal the 27 central bore 12 against pressure from above. A ram which carries additional mirror 1 image seals on the bottom portion of the ram, compared to Figures 1 and 2, will seal 2 the central bore 12 against pressure from above and below. Thus, while embodiments 3 are described which seal against pressure from below, these are only exemplary, and 4 not limiting, embodiments.
Each ram 18 includes a front end portion 24 (this being the portion which 6 extends into the central bore 12 in the extended position) and a rear end portion 26 7 (facing the end plugs 22, and which remains within the horizontal ram bore 14 in the 8 retracted and extended positions). The ram bores 14 are each of sufficient length to 9 accommodate the ram 18 in its fully retracted, open position or its fully extended, sealing position.
11 Each ram 18 is formed from a steel body component 28 which is generally 12 cylindrical in shape for a tight fitting seal in the ram bore 14. The body component 28 13 may be formed in multiple components which are assembled to form a cylindrical ram, 14 but a single piece steel body component is shown in the Figures 1-22.
The ram 18 is formed with a vertical groove 30 that runs along the front face 16 of the ram 18 to accommodate the polish rod P or other tubular member.
In Figures 2, 17 3, 5, 6, 7 and 10, the vertical radial groove is shown as generally semi-circular (in 18 horizontal cross section). The vertical groove 30 may be omitted if the front ends of 19 the rams 17, 18 are to function as blind rams 70 to seal against each other in the event that the polish rod is not present, as shown in Figure 8. Still alternatively, the vertical 21 groove may take the form of a vertical V-groove 34 running along the front face 32, as 22 shown in Figure 9, and as described in US Patent No. 7,673,674. The V-groove 34 is 23 sized to accommodate at least a portion of the circumference of the polish rod within 24 the groove 34. In the V-groove embodiment of Figure 9, one or more radial shaped, raised backing sections 36 (two shown in Figure 9) are formed at sealing locations 26 within the V-groove, these backing sections being sized to accommodate the polish rod 27 P in a tight fitting relationship.

1 As shown in Figure 2, each of the rams 18 include at least one rope packing 2 seal, shown as primary rope packing seal 40. The primary rope packing seal 40 is 3 formed from a length of rope packing which forms a closed loop on the outer surface of 4 the ram 18. The length of rope packing, and thus the primary rope packing seal 40 extends horizontally across the front face 32 of the ram 18, including across the vertical 6 groove 30, then generally rearwardly, and then upwardly around a portion of the outer 7 surface of the ram 18 and over the top portion 44 of the ram 18. Although not shown, 8 the primary rope packing seal 40 could alternatively, or in addition, extend over the 9 bottom portion 45 of the ram 18. In order to seal the central bore 12, the location where the primary rope packing seal 40 extends over the top portion 44 (or bottom portion 45) 11 is at a position on the ram 18 rearwardly of the front end portion 24, such that the seal 12 40 at the top portion 44 remains within the ram bore 14 when the ram 18 is fully 13 extended (see Figure 1), so as to seal to the ram bore 14. In Figure 2, the primary rope 14 packing seal 40 is shown to extend rearwardly along the side wall 42 of the ram 18, and then circumferentially upwardly across the top portion 44 of the ram 18.
Alternatively, 16 the primary rope packing seal could extend in an arcuate path, both rearwardly and 17 upwardly, such as shown in Figure 10 (labeled as primary rope packing seal 62, and 18 described below). Thus the terms "rearwardly", "upwardly" and "downwardly" as used 19 herein and in the claims with respect to the rope packing seals are not meant to refer to strict horizontal or vertical orientations, but are meant to include arcuate paths.
21 The primary rope packing seal 40 is preferably formed from a single length of 22 rope packing. While multiple lengths could be used, a single length minimizes the 23 number of joining ends to be accommodated, and thus minimizes weaknesses in the 24 seal. The primary rope packing seal 40 is held within a continuous first groove 46 (see Figure 7) machined into the steel body component 28 to underlie the path of the rope 26 packing seal 40. For the rams 18 shown in Figures 1-10, the continuous first groove 46 27 is shown to be adapted to accommodate overlapping end portions 48 (overlapping 28 ends) of the length of rope packing material in a manner to form a dynamic seal as the 29 BOP ram 18 is extended or retracted in the ram bore 14. The overlap is shown in the 1 Figures to be positioned at the top portion 44 of the ram 18, such that the overlapping 2 ends 48 are positioned side by side, and are directed generally perpendicularly to the 3 longitudinal axis L of the ram 18 (see Figure 6). In this way, as the ram 18 is moved 4 longitudinally along its axis L, the overlapping end portions 48 are compressed together by the extending/retracting movement of the ram 18. This is preferable to locating 6 overlapping end portions at a position such that they are parallel to the longitudinal axis 7 of movement of the rams 18, since parallel overlapped ends may tend to be pulled 8 apart by the extending/retracting movement of the ram 18. To accommodate the 9 overlapping side by side end portions 48, the continuous first groove 46 is machined, preferably at the top portion 44, with a widened groove portion 50 (see Figures 4 and 7) 11 sized to accommodate two diameters of the overlapping ends 48 of the rope packing 12 material in a compressed manner as the overlapping ends 48 lie side by side. This side 13 by side overlapping ends 48 arrangement is shown within the widened groove portion 14 50 in Figures 4 and 6.
Alternatively, a continuous first groove may be formed to accommodate joined 16 abutting ends of the rope packing. This is shown as a top view in the embodiments of 17 rams 18a, 18b and 18c in Figures 11-13. In these Figures, the primary rope packing 18 seal is shown at 40a, in a continuous first groove 46a (without a widened portion), but 19 with the ends 48a of the rope packing being cut on a diagonal angle, for example a 450 angle, at D such that they join (i.e., meet) with each other as joined abutting ends 48a 21 within the groove 46a. As above, the joined abutting ends 48a are preferably joined at 22 a location such that the ends are directed generally perpendicularly to, or diagonally 23 across, the longitudinal axis of the ram. This minimizes pulling apart action on the ends 24 48a as the ram 18a, 18b, 18c is extended and retracted in the ram bores 14.
The continuous first groove 46 is preferably sized with a depth dimension which 26 is slightly undersized relative to the diameter or side dimension of the rope packing.
27 The opening dimension of the continuous first groove 46 may also be undersize relative 28 to the diameter or side dimension of the rope packing. Either or both of these 1 techniques assist with the rope packing being held in the groove 46, while protruding 2 radially from the groove 46, to provide the seal to sealing surfaces of the housing 11. A
3 dove-tail shaped groove shape (see cross section of groove in Figure 4) is particularly 4 preferred to hold and retain the rope packing against dislodging. The groove 46 is best illustrated in Figure 7, in which the rope packing seal 40 is removed. A "dove-tail 6 shaped" groove is a groove which, in cross section, is sized smaller at its opening 7 dimension than it is at the bottom wall dimension of the groove, for example generally 8 trapezoidal shaped. However, other groove shapes such as generally round or square 9 (in cross section) may be used. Rope packing materials are particularly amenable to being compressed into grooves of different shapes, so as to be retained therein, while 11 also protruding therefrom.
12 As shown in Figure 2, the ram 18 may include a secondary rope packing seal 52.
13 This secondary rope packing seal 52 has particular application in higher pressure 14 sealing applications. The secondary rope packing seal 52 may be formed from a second single length of rope packing. The secondary rope packing seal 52 extends in a 16 continuous length, horizontally across the front face 32 of the ram 18, including across 17 the vertical groove 30 (preferably parallel and below the primary rope packing seal 40).
18 The rope packing seal 52 then extends rearwardly along the side wall 42 of the ram 19 body 28 (for example parallel and spaced below the primary rope packing seal 40), and upwardly to meet the primary rope packing seal 40. As shown in Figure 7 (rope packing 21 seals 40, 52 removed), the secondary rope packing seal 52 is held within a continuous 22 second groove 53 machined into the steel body component 28 to underlie the 23 secondary rope packing seal. The second groove 53 is preferably undersized in its 24 depth dimension, and preferably dove-tail shaped, as set forth above for first groove 46 and/or 46a. At the point where the secondary rope packing seal 52 meets the primary 26 rope packing seal 40, the grooves 53 and 46 are continuous with each other (see 27 Figure 7).
28 Alternatively, the secondary rope packing seal may extend rearwardly and then 1 upwardly (or downwardly), spaced from the primary rope packing seal, and around the 2 top portion or bottom portion of the ram to form a closed loop. In such embodiments, a 3 continuous second groove adapted to hold the secondary rope packing seal is adapted 4 to accommodate joined or overlapping ends of the rope packing as set out above for the primary rope packing seal.
6 In the Figures, the primary rope packing seal 40 is shown to extend rearwardly at 7 a location which is above the central portion 54 of the ram 18 (i.e, above a central 8 horizontal cross section line through the ram), and then over the top portion 44 of the 9 ram 18. In this manner, upward pressure along the central bore 12 assists in sealing the ram 18 in its extended sealing position, as the primary rope packing seal 40 is radially 11 compressed against the wall of the ram bores 14. The secondary rope packing seal 52 12 (if present), may be located horizontally below the primary rope packing seal 40, for 13 example at or near the central portion 54 of the ram 18 (i.e., closer to a central 14 horizontal cross section line through the ram). However, other locations of the rope packing seals 40, 52 are possible. For instance, if a bidirectional BOP
sealing ram is 16 needed, the BOP ram may be formed with a primary rope packing seal 40 such as 17 shown in the Figures, located above the central portion 54 of the ram 18, and with a 18 further rope packing seal (not shown) located as a mirror image below the central 19 portion of the ram 18.
It should be also be apparent that the rams 18 as shown in the Figures could be 21 rotated for positioning in the ram bores 14 such that the rope packing seals 40 and/or 22 52 are located below and at the central portion of the ram 18. Further, the rams 18 23 might be modified to include an upper rope packing (such as primary rope packing seal 24 40), a lower rope packing seal which may be a mirror image of the upper rope packing seal, and a central rope packing seal located horizontally between the upper and lower 26 rope packing seals, and which extends upwardly and downwardly at its sides to join 27 with the upper and lower rope packing seals.

1 The rear end portion 26 of the ram 18 may be formed with a circumferential seal 2 56 to seal the ram bores 14. In some BOP embodiments the end plugs or bonnet 22 3 may be used to seal the ends of the ram bores 14, so the circumferential seal 56 may 4 be omitted in such embodiments. This circumferential seal 56 may be formed from a length of rope packing material to comprise a circumferential rope packing seal 56. The 6 ram 18 may be formed with a continuous circumferential groove 58 at the rear end 7 portion 26 to underlie the rope packing circumferential seal 56. The circumferential 8 groove 58 may be formed to accommodate joined abutting ends 56a cut on a diagonal 9 angle at E (not shown in Figures 1-10 or 13, but shown at the top portion 44 of ram 18a in Figure 11). Alternatively, as shown in Figure 12 for ram 18b, the circumferential 11 groove 58b may be formed with a widened portion 75 to accommodate overlapped 12 ends 56b as described above for the primary rope packing seal 40. For the 13 circumferential seal 56, the location of the widened portion or joined abutting ends is 14 not critical, since the ends will be positioned perpendicular to the longitudinal axis of ram movement regardless of its location. In this way, the circumferential seal 56 also 16 functions as a dynamic seal.
17 Figure 10 illustrates alternate embodiment of a ram 60, in which the primary rope 18 packing seal 62 extends horizontally across the front face 32, including across the 19 vertical groove 30, and then extends rearwardly and upwardly along an arcuate path to meet at the top portion 44 of the ram 18, where overlapped end portions 63 are 21 accommodated as described above. Similarly, the secondary rope packing seal 64 22 extends horizontally across the front face 32, including across the vertical groove 30, 23 but spaced below the primary rope packing seal 62, and then extends rearwardly and 24 upwardly along an arcuate path to meet the primary rope packing seal 62.
The rope packings for these seals 62 and 64 are held in first, second grooves 66, 68 machined in 26 the body component 28, and positioned to underlie the seals 62, 64.
27 In the embodiment of Figure 8, the primary and secondary rope packing seals 28 40, 52 are as described above, but being a blind ram 70, no vertical groove is formed in 1 the front face of the ram 70.
2 In the embodiment of Figure 9, the primary and secondary seals 40, 52 are 3 generally as described above for Figure 2, but in a ram 72 formed with a vertical V-4 groove 34 to accommodate the polish rod P (not shown), the rope packing seals 40, 52 are formed on the radial backing sections 36, with the first and second grooves 46, 53 6 being machined horizontally across these backing sections 36. A
circumferential seal 7 56 is formed in the rear portion 26, as described above for Figure 2.
Other aspects of 8 the V-groove ram are more fully described in U.S. Patent No. 7,673,674.
9 The rope packing seals may be made from any known rope packing seal materials. Rope packings are available in many different forms, for example, braided, 11 twisted, woven and knitted. The rope packing may have a core material which differs or 12 is the same as the outer sealing material in composition, for example higher 13 temperature seal material may be used over a lower temperature core materials. As 14 well, the rope packing may be reinforced, for example with wire reinforcing materials such as steel, copper or stainless steel. The cross sectional shape may vary, such as 16 square, square with rounded corners, oval or circular, with square being preferred. The 17 continuous groove in the rams can be varied to accommodate and hold different cross 18 sectional shapes of rope packings. Examples of rope packings include braided cotton 19 twill, braided ramie fibre, braided tallowed rayon, tallowed flax graphite, braided jute yarn, braided glass fibre, aluminum foil, braided copper wire, braided PTFE
materials 21 (polytetrafluoroethylene such as Teflon ), Teflon impregnated braided asbestos, 22 braided ceramics, braided asbestos, and braided graphite. One exemplary material for 23 very high temperature applications is graphite rope packing which is stainless steel 24 reinforced, with a square cross section and a side dimension of about 0.8 cm.
Diameters of rope packing ranging from about 0.5 cm to 2 cm may be used. The rope 26 packing is threaded or pressed into the machined grooves 46, 53, 58 for example with a 27 hammer, or other known rope packing threading tools/devices.

1 Each of the primary and circumferential rope packing seals (and in some 2 embodiments the secondary rope packing seal), by being formed from a length of rope 3 packing arranged as a closed loop, and being held in a continuous groove which 4 accommodates either joined abutting ends, or overlapping ends in side by side relationship, is able to provide a dynamic seal on a blowout preventer ram.
6 In general, rope packings have been previously used only as static seals in the 7 wellhead equipment, where the seal remains generally static during seal 8 operation/energization. Examples of static rope packing seal applications include 9 annular seals on rotating or translating pipes, shafts or stems (ex.
stuffing box seals), or in place of 0-ring seals on tubulars such as tubing hangers. The BOPs and rams 11 described herein accommodate rope packings as a dynamic (moving) seal.
This 12 enables higher temperature rope packing materials to be used. For instance, graphite 13 reinforced stainless steel rope packing materials have been rated up to about 1000 F, 14 high enough for wellheads designed for steam injection or other very high temperature heating applications. Rope packing materials for very low temperature applications 16 may also be accommodated.
17 In the embodiments shown in Figures 14-23, the rams are shown to be 18 configured with front faces to abut and press against each other in the extended 19 position so as to impart a generally vertical movement to the opposing rams.
Alternatively, or in addition, the BOP rams shown in Figures 14- 23 may be configured 21 such that the seals across the front faces of the opposing rams have a vertical offset so 22 that the front face seals seal against each other, but with this vertical offset. The 23 multiple embodiments of Figures 1-23 are shown with like parts being labeled with the 24 same reference numerals.
Having reference to Figure 14, a production blowout preventer (BOP) is shown 26 generally at 100, to include a cross-shaped, pressure-containing steel housing 11 27 forming a central bore 12, extending generally vertically through the housing 11, and a 1 pair of co-axial horizontal ram bores 14. The ram bores 14 are slightly larger in 2 diameter than the central bore 12, as is common in BOP devices. Top and bottom 3 flange connectors 15, 16 to wellhead components located above and below the BOP
4 100 are shown, although alternate top and bottom connectors such as mentioned above may be used. The horizontal ram bores 14 intersect with the central bore 12.
6 The ram bores 14 are formed with a larger diameter than that of the central bore 12, 7 and sealing surfaces are formed across the central bore at the intersection of the bores 8 12, 14, all as is generally known in the art. The polish rod P is shown in place in the 9 central bore 12. The polish rod P is an example of a tubular member which may be present in the central bore 12.
11 A pair of generally cylindrical BOP rams 118a, 118b are shown in Figure 14.
12 Each of the rams 118a, 118b may be formed in multiple parts, but are generally 13 cylindrically shaped when assembled for close fitting relationship in, and optionally for 14 sealing to, the ram bores 14. The rams 118a, 118b are generally formed as steel bodied rams, although one or more coatings may be formed on the rams or portions of 16 the rams. The rams 118a, 118b are locked onto the ends of ram screws 20, which 17 extend through end plugs or bonnets 22 at the outer ends of the ram bores 14. The 18 ram screws 20 can be turned to extend or retract the rams 118 into or out of the central 19 bore 12 with mechanical screw jacks which can operate on the external ends of the ram screws 20. Each ram screw 20 is connected at the rear face 133 of the ram 118a, 21 118b, typically in a T-slot 135 (see Figure 19), in a manner known in the art. The ram 22 screws 20 can be extended and retracted with other types of ram actuating 23 mechanisms as set out above. The ram screws 20, with the ram actuating 24 mechanisms, extend and retract the rams 118a, 118b between the open position, in which the rams 118a, 118b are retracted from the central bore 12, and the closed, 26 sealing position, in which the opposing rams 118a, 118b are extended to seal against 27 each other, around the polish rod P if present, upwardly against the ram bores 14, and 28 across the sealing surfaces of the central bore 12 to seal the central bore from pressure 29 below.

1 As above, one of the rams, along with the ram bores, may be adapted to include 2 and accommodate an extended central bore sealing section as described in U.S.
3 Patent 7,552,765. As well, the ram bores 14 and corresponding rams 118a, 118b are 4 not necessarily strictly cylindrical in shape. The rams and bores may take alternate shapes, such as oval in cross section, as is known in the art. As well, as mentioned 6 above, the rams 118a, 118b, and the ram screws 20 may be rotated through 180 to 7 seal against pressure from above, in which case, the rams 118a, 118b seal as above 8 for Figure 14, but downwardly against the ram bores 14 (instead of upwardly as above).
9 As best shown in Figure 15, on the right hand ram body 118a of Figure 14, but also applying with general mirror symmetry to left hand ram body 118b, the ram 118a 11 includes a front end portion 124 (this being the portion which extends into the central 12 bore 12 in the extended position) and a rear end portion 126 (facing the end plugs 22, 13 and which remains within the horizontal ram bore 14 in the retracted and extended 14 positions). The ram bores 14 are each of sufficient length to accommodate the ram 118a (or 118b) in its fully retracted, open position or its fully extended, sealing position.
16 Each ram 118a, 118b is formed from a steel body component 128 which is 17 generally cylindrical in shape for a tight fitting seal in the ram bore 14. The body 18 component 128 may be formed in multiple components, as in Figure 23 which are 19 assembled to form a cylindrical full body ram, but a single piece steel body component is shown in the Figures 14-22.
21 The ram 118a,118b may be formed with a vertical groove 130 that runs along the 22 front face 132 of the ram 118b, 118b to accommodate the polish rod P or other tubular 23 member. In Figures 17, 18 and 22 the vertical radial groove is shown as generally 24 semi-circular (in horizontal cross section). The vertical groove 130 may be omitted if the front ends of the rams 118a, 118b are to function as blind rams 170 to seal against 26 each other in the event that the polish rod P is not present, as shown in Figure 21. Still 27 alternatively, the vertical groove may take the form of a vertical V-groove 134 running 1 along the front face 132, as shown in the ram 172 of Figure 20, and as described in 2 greater detail in US Patent No. 7,673,674. The V-groove 134 is sized to accommodate 3 at least a portion of the circumference of the polish rod P within the groove 134. In the 4 V-groove embodiment of Figure 20, one or more radial shaped, raised backing sections 136 (two shown in Figure 20, one for each seal) are formed at sealing locations within 6 the V-groove 134. These backing sections 136 being sized to accommodate the polish 7 rod P in a tight fitting relationship in order to seal to the polish rod P.
8 In Figure 14, the pair of rams 118a, 118b are shown being moved into the 9 extended position, but not yet in the fully extended, sealing position.
As shown in Figure 14, and also in Figure 15, the front face 132 of each of the rams 118a, 118b is 11 formed with mirror symmetry, with a leading edge portion 175 adapted to first abut or 12 first contact the leading edge portion 175 of the opposing ram 118a, 118b in advance of 13 the remainder of the front face 132 of the opposing ram 118a, 118b. In this way, the 14 leading edge portions 175 of the opposing rams 118a, 118b abut and are then pressed against each other as the rams 118a, 118 b continue to be moved into the extended 16 position by the ram screws 20. This continued pressing against each other of the 17 leading edge portions 175 imparts a generally vertical movement to the opposing ram 18 118a, 118b. In the embodiments of Figures 14-23, the generally vertical movement is 19 generally upwardly, however, if the rams were rotated 180 , the generally vertical movement is generally downwardly. The generally vertical movement may also be 21 envisaged as a generally upward or downward rotating movement as the rams move 22 through an angle relative to the center axis of the rams bores C.
23 As shown in Figures 14 and 15, each of the rams 118a, 118b include at least 24 one seal, shown as a primary rope packing seal 140. This seal 140 could alternatively be formed of an elastomeric or thermoplastic material, although the rope packing seal 26 materials may be selected for very high or very low temperature environments in which 27 the elastomeric or thermoplastic seal materials may not function as well, or at all. The 28 primary rope packing seal 140 is formed from a length of rope packing which forms a 1 closed loop on the outer surface of the ram 118a, 118b. The length of rope packing, 2 and thus the primary rope packing seal 140 extends horizontally across the front face 3 132 of the ram 118a, 118b, including across the vertical groove 130, then generally 4 rearwardly, and then upwardly around a portion of the outer surface of the ram 118a, 118b and over the top portion 144 of the ram 118a, 118b. Although not shown, the 6 primary rope packing seal 140 could alternatively, extend over the bottom portion 145 of 7 the ram 118a, 118b. In order to seal the central bore 12, the location at which the 8 primary rope packing seal 140 extends over the top portion 144 (or bottom portion 145) 9 is at a position on the ram 118a, 118b rearwardly of the front end portion 124, such that the seal 140 at the top portion 144 remains within the ram bore 14 when the ram 118a, 11 118b is fully extended so as to seal to the ram bore 14. Figure 14 shows the seal 140 12 at the top portion 144 as being located within the ram bores 14, and thus rearwardly of 13 the front end portion 124. In Figures 14 and 15, the primary rope packing seal 140 is 14 shown to extend rearwardly along the side wall 142 of the ram 118a, 118b, and then circumferentially upwardly over the top portion 144. Alternatively, the primary rope 16 packing seal could extend in an arcuate path, both rearwardly and upwardly, such as 17 shown in Figure 22 (labeled as primary rope packing seal 162 on ram 173). Thus the 18 terms "rearwardly", "upwardly" and "downwardly" as used herein and in the claims with 19 respect to the rope packing seals are not meant to refer to strict horizontal or vertical orientations, but are meant to include arcuate paths.

22 As shown in Figures 14 and 15, the leading edge portions 175 are located above 23 the primary rope packing seal 140, adjacent the top portion 144 of the ram 118a, 118b.
24 When the generally vertical movement is imparted to the rams 118a, 118b as they are moved into the extended position, the seals 140 on the front faces 132 are brought into 26 sealing engagement with each other, and the seal 140 extending over the top portion 27 144 of the ram 118a, 118b is energized as the ram is moved upwardly against the ram 28 bore 14. In an embodiment in which the rams 118a, 118b are rotated 180 compared 29 to Figure 14, the leading edge portions may be located below the seal 140, and the generally downward movement imparted in the extended position energizes the seal 1 140 downwardly against the ram bore 14.
2 In the embodiment shown in Figures 14 and 15, the front faces 132 of the rams 3 118a, 118b are formed with an inclined portion 177 such that a plane through the 4 inclined portion 177 is inclined toward the central bore 12, and in a manner such that the inclined portions 177 on opposing rams 118a, 118b are brought into contact with 6 each other by the generally vertical movement imparted to the opposing rams 118a, 7 118b. The seal 140 may be located on the inclined portion 177, so that as the inclined 8 portions 177 on opposing rams 118a, 118b are brought into contact with each other, the 9 seals 140 are energized against each other, and against the polish rod P, if present.
In the embodiment of Figures 14 and 15, the leading edge portion 175 is located 11 adjacent the top portion 144, and the front face 132 of the ram 118a, 118b forms one 12 inclined portion, such that a plane through the front face 132 is inclined top to bottom 13 toward the central bore 12. In this embodiment, the inclined portions 177 are shown to 14 leave a horizontal gap 179 between the bottom portions 145 when the rams reach the position across the central bore when the leading edge portions 175 of the opposing 16 rams 118a, 118b first contact (see Figure 14 for gap 179). This gap 179 is sized to 17 close as the rams 118a, 118b are moved into the fully extended, sealing position. In 18 general, the gap 179 is sized by an angle formed between a plane through the inclined 19 portion 177 and a vertical plane through the central axis of the central bore 12. This angle will vary with the size of the BOP and the BOP rams, but is generally less than 10 21 degrees, such as less than 5 degrees, such as between about 1 and 3 degrees, and 22 such as between about 2 and 3 degrees. In embodiments in which the rams are 23 rotated 180 compared to Figure 14, this gap 179 will be present at the top of the rams.
24 As best shown in Figure 14, to facilitate imparting the generally vertical movement to the ram 118a, 118b, each of the ram screws 20 is connected to the rear 26 face 133 of the rear end portion 126 of the ram 118a, 118b at a point below a the 27 center axis C of the ram bores 14 (which is also below the longitudinal axis L of the 1 rams 118a, 118b). In Figure 14, the ram screw center line S is shown to be below 2 center axis C and longitudinal axis L. With this feature, as the rams screw 20 pushes 3 on the rear end portion 126, the off center force (below the center in Figure 14) 4 facilitates an upward rotation of the ram 118a, 118b, and thus facilitates the generally upward movement of the ram to assist in the sealing actions for the seal 140 described 6 above. In alternate embodiments, in which the ram 118a, 118b is rotated 180 the ram 7 screw 20 may be connected above the center axis of the ram bore 14 to facilitate a 8 downward movement of the ram.
9 To further facilitate imparting the general vertical movement to the ram 118a, 118b, and to allow the ram to flex in the ram bore 14, the front face of the ram 118a, 11 118b is formed with a cut away portion 182 located above or below the seal 140. In 12 Figures 14 - 22, the cut away portion 182 is shown as a horizontal slot 184 below the 13 seal 140, extending across the front face 132 and rearwardly in the ram.
In an alternate 14 embodiment in which the rams are rotated through 180 compared to Figure 14, the cut away portion 182 could be located above the seal. In Figures 14-22, the horizontal slot 16 184 is shown to extend rearwardly of the front end portion 124 of the ram to provide a 17 significant flex movement to the ram. However, in alternate embodiments, depending 18 on the size of the rams and the size of the front end gap 179, and thus the rigidity of the 19 steel bodied ram, the horizontal slot may extend rearwardly to a greater or lesser extent to provide the desired amount of flex to initiate the vertical movement and sealing 21 actions of the rams. As an alternative to the horizontal slot, the cut away portion 182 22 may remove a portion of the ram extending across the entire front face 132 at a location 23 above or below the seal (below the seal when configured as in Figure 14).
24 In an alternate embodiment shown in Figure 16, the leading edge portion 175 is formed on the ram 171 (and on an opposing ram formed with general mirror symmetry) 26 as a flattened planar portion 180. The flattened planar portion 180 may be formed 27 adjacent the top portion 144 of the ram 171. A plane through the flattened planar 28 portion 180 is generally vertical. By forming the leading edge portion 175 as a flattened 1 planar portion 180, the ram 171 has more planar surface area over with to abut the 2 flattened planar portion of the opposing ram at the point of first contact, and to press 3 against the flattened planar portion of the opposing ram in order to impart the generally 4 vertical (upward for ram 171) movement to the ram 171. In Figure 16, the ram 171 is formed with the inclined portion 177 located directly below the leading edge portion 175, 6 and inclined from the leading edge portion to the bottom portion toward the central 7 bore. As noted above for the ram 118a, the ram 171 may be rotated 180 for sealing 8 downwardly in alternate embodiments.
9 The leading edge portions 175 and the inclined portions 177 may be alternately configured than as shown in the figures, provided the leading edge portion 175 is the 11 point of first contact with the opposing rams (apart from any protruding seals), and 12 provided these portions and any other surfaces at the front face 132 allow for the 13 generally vertical movement and sealing actions of the ram, as above-described, in the 14 extended position.
As described above, the rams 118a, 118b may be formed with a primary rope 16 packing seal 140. In Figures 14 - 21, the primary rope packing seal 140 is configured 17 similarly to the embodiment shown in Figures 1-2, formed from a single length of rope 18 packing material held in a continuous first groove 146 (see Figure 17, with the rope 19 packing seals removed) and having overlapping end portions 148 held in side by side relationship at the top portion 144 of the ram in a widened groove 150. In Figure 22, 21 the primary rope packing seal 162 is configured similarly to the embodiment shown in 22 Figure 10 in which the primary rope packing seal 162 follows a generally arcuate path in 23 the continuous first groove 166, over the top portion 144 such that the overlapping end 24 portions 163 are accommodated in a widened portion of the continuous first groove 166, as described above.
26 A secondary rope packing seal 152 may be included, as shown in Figures 14-22.
27 In Figures 14-21, the secondary rope packing seal 152 is configured similarly to the 1 embodiment of Figures 1-2, except that the ends 152a of second length of rope packing 2 meet the primary rope packing seal 140 at the side wall 142 of the ram with overlap 3 between the primary and secondary rope packing seals 140, 152. The secondary rope 4 packing seal 152 extends horizontally across the front face 132, including across any vertical groove 130, preferably parallel and spaced below the primary rope packing seal 6 140, held within a second groove 153 (see Figure 17 with the rope packing seals 7 removed). The secondary rope packing seal 152, within second groove 153 extends 8 rearwardly along the side wall 142 of the ram, generally spaced from and below the 9 primary rope packing seal 140, and then upwardly to meet the primary rope packing seal 140. In Figure 22, the secondary rope packing seal 164 is similar to the 11 embodiment shown in Figure 10, with the secondary rope packing seal 164 following a 12 generally arcuate path in the second groove 168 to meet the primary rope packing seal 13 162 at the side wall 142.
14 As with the embodiments of Figures 1-13, the first and second grooves may be dove-tail shaped in cross section to retain the first and second lengths or loops of rope 16 packing.
17 As best shown in Figure 14, in order to limit a pulling action of the primary rope 18 packing seals 140 at the front face 132 of the ram 118a, 118b as the seals 140 19 disengage from each other after sealing against each other, a vertical offset between the seals 140 on opposing rams 118a, 188b may be added. As shown in Figure 14, the 21 primary rope packing seal 140 on ram 118a is located with a vertical offset relative to 22 the primary rope packing seal 140 on the opposing ram 118b, such that the seal 140 on 23 ram 118a is located slightly vertically lower on the front face 132 than is the seal 140 on 24 opposing ram 118b. However, the seals 140 on the opposing rams 118a, 118b still overlap slightly so that they may still seal against each other in the extended position, 26 but they seal against each other with the vertical offset. In this manner, as the rams 27 118a, 118b are retracted from the extended sealing position, the seals 140 are less 28 likely to pull each other out of the underlying first grooves 146.

1 Similarly, the secondary packing seals 152 are positioned across the front face 2 132 of the ram 118a with a similar vertical offset relative to the secondary rope packing 3 seal 152 on the front face 132 of the opposing ram 118b, such that in the extended 4 position, the secondary rope packing seals 152 on the opposing rams 118a, 118b seal against each other but with the vertical offset.
6 This vertical offset feature of the front face seals 140, 152 is a feature for which 7 the opposing rams 118a, 118b do not share mirror symmetry. However, as is apparent 8 from the Figures 14-23, and from the description of the embodiments of Figures 14-23 9 herein, other features of the opposing rams are formed with mirror symmetry, including the leading edge portions, the inclined portions, the cut-away portions and the ram 11 screws off-center connections.
12 Other embodiments of the primary and secondary rope packing seals, and the 13 optional inclusion of a circumferential rope packing seal located rearwardly of the first 14 and second rope packing seals, may be included, as set out above for the embodiments of Figures 1-13. Any of the primary, secondary and circumferential rope 16 packing seals may be formed from a continuous loop of rope packing material, in which 17 case overlapping or adjoining two ends of the lengths of rope packing do not need to be 18 accommodated, and a continuous groove may be used to hold each loop of rope 19 packing.
In the embodiment shown in Figure 23, a production BOP ram 200 is shown 21 generally configured to be positioned in the ram bores 14 of a BOP
housing 11 such as 22 shown in Figure 14. In the description herein, the ram 200 is described as if positioned 23 in the BOP housing 11 of Figure 14, with like parts being labeled with the same 24 reference numbers. The ram 200 has a front end portion 202, a rear end portion 204, a top portion 206, a bottom portion 208 and side walls 209. In an extended position, the 26 front end portion 202 extends across the central bore 12 and the rear end portion 204 is 27 within the ram bore 14. In a retracted position, the ram 200 is within the ram bore 14.

1 The ram 200 is shown to consist of a steel body component 210 forming the bottom 2 portion 208 of the ram 200, and a steel seal component 212 forming the top portion 206 3 of the ram 200. When assembled, the body component 210 and the seal component 4 212 form a full body ram. Each of the opposing rams 200 is formed generally with mirror symmetry to each other, and are each generally cylindrical in shape for a tight 6 fitting seal in the ram bore 14. The body component 210 has a front portion 214, a rear 7 portion 216, a front end 218 and a rear end 220. The seal component 212 has a front 8 portion 222, a rear portion 224, a front end 226, a rear end 228 and a front face 230.
9 The seal component 212 is shaped to fit into a cut-out 232 formed at the front portion 214 of the body component 210. The cut-out 232 provides a seal support 11 surface 234 to support the seal component 212 in both a vertical and horizontal 12 direction. The cut-out 232 may be generally L-shaped, as shown. However, similarly to 13 that described in U.S. Patent 7,137,610, the cut-out portion may have an alternate 14 shape, such as a wedge shape. The rear end 216 of the body component 210 is formed with a central T-slot 236 to connect and lock onto the end of the ram screws 20, 16 such as shown in Figure 14.
17 The seal component 212 includes a primary rope packing seal 238 formed 18 entirely on the outer surface of the seal component 212. The primary rope packing seal 19 238 extends across the front face 230 of the seal component 212, rearwardly and then upwardly over the top portion 206 of the ram 200 at a position rearwardly of the front 21 end portion 202 of the ram 200. As with the embodiments of Figures 14-23, the primary 22 rope packing seal 238 is formed from a first length or loop of rope packing, and is held 23 within a continuous first groove 240 formed similar to the continuous first groove in the 24 embodiments described hereinabove.
As set out above for the embodiments of Figure 14, the primary rope packing 26 seal 238 may be positioned across the front face 230 of the seal component 212 with a 27 vertical offset relative to the primary rope packing seal 238 on the front face 230 of the 1 seal component 212 of the opposing ram 200, such that in the extended position, the 2 primary rope packing seals 238 on the opposing rams 200 seal against each other but 3 with the vertical offset.
4 A secondary rope packing seal 239 may be included on the seal component similar to that shown in Figures 14-22. The secondary rope packing seal 239 extends 6 horizontally across the front face 230 of the seal component 212, including across any 7 vertical groove which may be present, preferably parallel and spaced below the primary 8 rope packing seal 238, and held within a second groove 241. The secondary rope 9 packing seal 239, within second groove 241 extends rearwardly along the side walls 209 of the ram 200, generally spaced from and below the primary rope packing seal 11 238, and then upwardly to meet the primary rope packing seal 238.
12 Similarly to above described embodiments, the secondary packing seal 239 may 13 be positioned across the front face 230 of the seal component 212 with a vertical offset 14 relative to the secondary rope packing seal 239 on the opposing ram 200, such that in the extended position, the secondary rope packing seals 239 on the opposing rams 200 16 seal against each other but with the vertical offset. As mentioned above for the 17 embodiment of Figure 14, this vertical offset feature will generally be a feature for which 18 the opposing rams 200 do not share mirror symmetry.
19 Each of the body and seal components 210, 212 are formed with a pair of aligned horizontal pin bores 242, 244 respectively, to accommodate a pair of side by 21 side connecting pins 246. Both the pin bores 242, 244 and one of the connecting pins 22 246 are shown in dotted outline in the side view of Figure 23. One design of the 23 connecting pins 246 is shown in Figure 23, but alternate embodiments are described in 24 U.S. Patent 7,137,610.
Each of the body and seal components 210, 212 may be formed with a vertical 26 radial groove 247 that runs along the front of the assembled ram 200 to accommodate 1 and seal against the polish rod P, if present. The vertical radial groove 247 may be 2 omitted if the front ends of the rams 200 are to function as blind rams to seal against 3 each other in the event that the polish rod is not present. As shown, in its assembled 4 and connected form with the body component 210, the front end 226 of the seal component 212 protrudes beyond the front end 218 of the body component 210 by a 6 horizontal distance "d". This protruding front end 226 of the seal component 212 acts 7 as a leading edge portion of the ram 200, similar to the leading edge portion 175 8 described above for the embodiments of Figures 14-22.
9 The seal component 212 is generally semi-cylindrical in shape such that, when connected to the body component 210, the ram 200 is a full bore ram, conforming to 11 the horizontal ram bores 14. In the embodiment shown, the seal component 12 includes the primary rope packing seal 238 at its outer circumference.
As more fully 13 explained below, when the rams 200 are advanced into the extended position against 14 the polish rod P, the primary rope packing seal 238 encircles the central bore 12 and thus functions to seal the central bore 12 when the opposing rams 200 are fully 16 engaged against the polish rod P.
17 The L-shaped cut-out 232 of the body component 210 is formed with a slightly 18 inclined (front to rear), acutely angled seal support surface 234. A
similarly angled 19 lower surface 250 is formed on the seal component 212, such that in the extended position, the seal component 212 rides upwardly and rearwardly on the seal support 21 surface 234 of the body component 210, as the rams 200 are moved into the extended, 22 sealing position to close the central bore 12. In its assembled, connected state, when 23 not in the extended position, the seal component 212 is seated in the L-shaped cut-out 24 232, and a gap 252 remains at the rear end 228 of the seal component 212 between the components 210, 212. The horizontal distance "d" by which the front end 226 of the 26 seal component 212 protrudes beyond the body component 210 is slightly greater than 27 the horizontal width of the gap 252, to ensure a sealing action to the polish rod P.

1 In the extended position the opposing rams 200 seal against each other, against 2 the polish rod P, and outwardly against the horizontal ram bores 14 and the sealing 3 surfaces of the central bore 12 to effectively seal the central bore 12 of the BOP
4 housing 11 against pressure from below. As the rams 200 are initially advanced in the ram bores 14, the protruding front ends 226 of the seal components 212 meet each 6 other around the polish rod P, causing the seal components 212 to ride upwardly and 7 rearwardly on the acutely angled seal support surfaces 234 of the body components 8 210, until the gaps 252 between the seal and body components 212, 210 are closed, 9 and the primary rope packing seals 238 on the seal components 212 are pressed against each other to seal the front faces 230 of the seal components 212 and to seal 11 around the polish rod P. As well, the rearward and upward movement of the seal 12 component 212 on the seal support surface 234 of the body component 210 moves the 13 primary rope packing seal 238 located at the top portion 206 of the ram 200 upwardly to 14 seal against the ram bore 14. The primary rope packing seal 238 also seals against the sealing surfaces of the central bore 12.
16 Alternate embodiments of the seal and body components will be apparent to one 17 skilled in the art from the embodiments described in U.S. Patent 7,137,610, and such 18 embodiments fall within the claims of this application.
19 The rams 200 described herein include the seal component 212 above the body component 210. However, it should be apparent that the rams 200 could be rotated 21 such that the seal component 212 is on the bottom. Further, the body and seal 22 components 210, 212 may be modified such that both top and bottom seal components 23 are carried on a more generally T-shaped body component to form the cylindrical rams.
24 Furthermore, the components 210, 212 could be oval shaped rather than strictly cylindrical. Furthermore, the body component 210 could be two piece if desired. These 26 and other modifications will be apparent to persons skilled in the art, and are intended 27 to fall within the scope of the present invention.

1 The embodiments of the BOP as described above and/or the BOP rams 2 described above may be adapted to be included in a composite wellhead assembly 3 including, between a top connector and a bottom connector, together with one or more 4 of the following components, in any sequence, adapters, valves, gate valves, flow tee, additional blowout preventers, and polish rod clamp. To that end, attention is directed 6 to the devices disclosed in the following U.S. Patents, all of which are commonly owned 7 by Stream-Flo Industries Ltd.: U.S. 5,743,332, issued April 28, 1998, entitled "Integral 8 Wellhead Assembly for Pumping Wells"; U.S. 6,457,530, issued October 1, 2002, 9 entitled "Wellhead Production Pumping Tree"; U.S. 6,176,466, issued January 23, 2001, entitled "Composite Pumping Tree with Integral Shut-Off Valve"; and U.S.
11 6,595,278, issued July 22, 2003, entitled "Assembly for Locking a Polished Rod in a 12 Pumping Wellhead". Each of these patents discloses wellhead equipment used in 13 connection with pumping oil wells, but in a composite form, meaning that one or more 14 functional components of a conventional pumping tree are included in an integral body housing between a top and a bottom connector. Such components may include a shut 16 off valve, a blowout preventer, a flow tee and an adapter. As a composite wellhead, 17 the components are included in an integral tubular body formed from a single piece of 18 steel, and forming an axial, vertical or central fluid flow bore extending therethrough.
19 Multiple side openings are formed in the body, each communicating with the vertical bore, in order to house the valve, BOP and flow tee components. The body includes a 21 bottom connector for connection with a wellhead component located therebelow, for 22 example a flanged top connection of a tubing head. This bottom connection might be a 23 studded down connection, or any other bottom connector such as a flanged connection, 24 clamp-hub connection, rotatable flange connection, welded connection or threaded connection. The body may include a valve housing section above the bottom 26 connection to house a conventional gate valve assembly operative to open or close the 27 central bore. Above the valve housing section may be a first BOP housing section, 28 adapted to house the ram assembly components of one or more of the Figures 29 described above. A second BOP housing section may optionally be formed in the body above the first BOP housing section, housing same or different ram or polish rod clamp 1 components as described above. Above the second BOP housing is typically a flow tee 2 housing section for connection with a conventional flow line, through which well fluid is 3 produced. The body forms a top connector at its upper end for connection with the 4 wellhead component located thereabove, typically a stuffing box. The top connector may include studded connectors, but any other type of connector as indicated above for 6 the bottom connector, may be substituted, as known in the art. As indicated, this is only 7 one exemplary composite wellhead assembly. The components may be provided in 8 different sequences, and may be varied, added or omitted as is appropriate for the 9 needs of a particular wellhead.
All references mentioned in this specification are indicative of the level of skill in 11 the art of this invention. If any inconsistency arises between a cited reference and the 12 present disclosure, the present disclosure takes precedence. Some references provide 13 details concerning the state of the art prior to the filing of this application, other 14 references may be cited to provide additional or alternative device elements, additional or alternative materials, additional or alternative methods of analysis or application of 16 the invention.
17 The terms and expressions used are, unless otherwise defined herein, used as 18 terms of description and not limitation. There is no intention, in using such terms and 19 expressions, of excluding equivalents of the features illustrated and described, it being recognized that the scope of the invention is defined and limited only by the claims 21 which follow. Although the description herein contains many specifics, these should not 22 be construed as limiting the scope of the invention, but as merely providing illustrations 23 of some of the embodiments of the invention.
24 One of ordinary skill in the art will appreciate that elements and materials other than those specifically exemplified can be employed in the practice of the invention 26 without resort to undue experimentation. All art-known functional equivalents, of any 27 such elements and materials are intended to be included in this invention. The invention 1 illustratively described herein suitably may be practiced in the absence of any element 2 or elements, limitation or limitations which is not specifically disclosed herein.

Claims (40)

WHAT IS CLAIMED IS:

1. A ram type blowout preventer, comprising:
a housing forming a central bore extending generally vertically through the housing, and a pair of ram bores extending radially outwardly in opposite directions through the housing and intersecting the central bore;
a steel bodied ram positioned in each of the pair of ram bores to provide opposing rams, the ram having a front end portion, a rear end portion, a top portion and a bottom portion and being adapted for sliding movement in the ram bore between an extended position, with the front end portion extending across the central bore and the rear end portion within the ram bore, and a retracted position within the ram bore, the ram being configured with a front face to seal against the front face of the opposing ram and to accommodate and seal against a tubular member or rod, if present in the central bore;
a ram actuating mechanism connected to the rear end portion of the ram for extending and retracting the ram between the extended and retracted positions;
a seal on the ram, the seal extending across the front face, then rearwardly, and then either upwardly over the top portion or downwardly over the bottom portion, at a position rearwardly of the front end portion; and the front face of the ram forming a leading edge portion located either above or below the seal so that, as the opposing rams are moved into the extended position, the leading edge portions of the opposing rams abut and press against each other, imparting a generally vertical movement to the opposing rams so that the rams rotate upwardly or downwardly through an angle relative to a center axis of the ram bores to bring the seals on the front faces into sealing engagement with each other and to energize the seals extending over the top portion or the bottom portion against the ram bores;
such that, in the extended position, the seals on the opposing rams seal against each other, against the tubular member or rod if present, and against the ram bores to seal the central bore.

2. The blowout preventer of claim 1, wherein the front face of the ram includes an inclined portion such that a plane through the inclined portion is inclined toward the central bore, and the inclined portion being adapted to be brought into contact with the inclined portion on the opposing ram by the generally vertical movement imparted to the opposing rams.

3. The blowout preventer of claim 2, wherein the seal is located on the inclined portion of the ram.

4. The blowout preventer of claim 2, wherein the ram actuating mechanism includes a ram screw connected to the rear end portion of the ram at a point either above or below the center axis of the ram bore to facilitate imparting the generally vertical movement to the ram.

5. The blowout preventer of claim 1 or 3, wherein the front face of the ram is formed with a cut away portion located above or below the seal to allow the ram to flex in the ram bore.

6. The blowout preventer of claim 4, wherein the front face of the ram is formed with a cut away portion located above or below the seal to allow the ram to flex in the ram bore.

7. The blowout preventer of claim 6, wherein the cut away portion comprises a horizontal slot extending across the front face and rearwardly in the ram.

8. The blowout preventer of claim 7, wherein the horizontal slot extends rearwardly of the front end portion of the ram.

9. The blowout preventer of claim 7, wherein the inclined portion of the ram is inclined such that the plane through the inclined portion forms an angle relative to a vertical plane which is less, than 10 degrees.

10. The blowout preventer of claim 9, wherein the angle is less than 5 degrees.

11. The blowout preventer of claim 9, wherein the angle is between 1 and 3 degrees.

12. The blowout preventer of claim 9, wherein the angle is between 2 and 3 degrees.

13. The blowout preventer of any one of claims 9-12, wherein the front face of the ram comprises the inclined portion, such that a plane through the front face is inclined top to bottom toward the central bore, and such that the leading edge portion is formed adjacent the top portion of the ram.

14. The blowout preventer of any one of claims 9-12, wherein the leading edge portion of the ram is a flattened planar portion formed adjacent either the top portion or the bottom portion of the ram, such that a plane through the flattened portion is generally vertical.

15. The blowout preventer of any one of claims 9-14, wherein:
the leading edge portion of the front face is located adjacent the top portion of the ram;
the inclined portion is located directly below the leading edge portion and is inclined from the leading edge portion to the bottom portion toward the central bore;
the seal extends over the top portion of the ram, such that the generally vertical movement imparted to the ram energizes the seal upwardly against the ram bore;
the ram screw is connected to the rear portion of the ram at a point below the center axis of the ram bore; and the horizontal slot is located below the seal.

16. The blowout preventer of any one of claims 1-15, wherein the seal is formed from a length or loop of rope packing.

17. The blowout preventer of any one of claims 1-15, wherein the seal comprises a primary rope packing seal formed on the ram from a first length of rope packing having two ends, the primary rope packing seal extending horizontally across the front face, then rearwardly, and then upwardly over the top portion at a position rearwardly of the front end portion, the primary rope packing seal being held as a closed loop in, so as to protrude radially outwardly from, a continuous first groove formed in the ram, such that in the extended position the primary rope packing seals on opposing rams seal against each other on opposing front faces, against the tubular member or rod if present, and against the ram bores to seal the central bore.

18. The blowout preventer of claim 17, wherein the primary rope packing seal extends across the front face of the ram with a vertical offset relative to the primary rope packing seal on the front face of the opposing ram, such that in the extended position, the primary rope packing seals on the opposing rams seal against each other but with the vertical offset.

19. The blowout preventer of claim 18, wherein the continuous first groove is adapted to accommodate the two ends of the first length of rope packing as joined abutting ends or as overlapping ends.

20. The blowout preventer of claim 19, wherein the continuous first groove is adapted to accommodate the joined abutting ends of the first length of rope packing at the top portion of the ram such that the joined abutting ends are oriented generally perpendicular to, or diagonally across, a longitudinal axis of movement of the ram in the ram bore.

21. The blowout preventer of claim 19, wherein the continuous first groove forms a widened portion at the top portion of the ram such that the overlapping ends of the first length of rope packing are held side by side and are oriented generally perpendicular to a longitudinal axis of movement of the ram in the ram bore.

22. The blowout preventer of claim 21, further comprising a secondary rope packing seal formed on the ram from a second length or loop of rope packing extending horizontally across the front face, and being spaced from the primary rope packing seal, the secondary rope packing seal being held in, so as to protrude radially outwardly from, a second groove formed in the ram, wherein the secondary rope packing seal extends across the front face of the ram with a vertical offset relative to the secondary rope packing seal on the front face of the opposing ram, such that in the extended position, the secondary rope packing seals on the opposing rams seal against each other but with the vertical offset.

23. The blowout preventer of claim 22, wherein:
the second groove extends across the front face of the ram and then generally rearwardly to meet the continuous first groove;
the secondary rope packing seal is formed from the second length of rope packing to form two ends; and the second length of rope packing extends rearwardly within the second groove such that each of the two ends of the second length of rope packing meets the primary rope packing seal.

24. The blowout preventer of claim 22, wherein the first groove and the second groove are generally dove-tail shaped in cross section to hold the first or second length of rope packing.

25. The blowout preventer of claim 22, wherein the front face of the ram is formed as a blind ram such that the front faces of the opposing rams seal against each other in the extended position to seal the central bore.

26. The blowout preventer of claim 22, wherein the front face of the ram is formed with a vertical groove to accommodate the tubular member or rod.

27. The blowout preventer of claim 26, wherein the vertical groove is a radial groove.

28. The blowout preventer of claim 26, wherein the vertical groove is V-shaped to accommodate at least a portion of the circumference of the tubular member or rod within the V-groove, and wherein the primary rope packing seal and the secondary rope packing seal extend across a raised radial backing section formed in the V-groove to seal to the tubular member or rod.

29. The blowout preventer of any one of claims 17 to 28, wherein:
the first length of rope packing, and the second length of rope packing if present, are formed of a rope packing material in a braided, twisted, woven or knitted form;
the steel bodied ram is formed as a single piece steel bodied ram;
the ram bores are generally cylindrical; and the rams are generally cylindrical.

30. The blowout preventer of any one of claims 16 to 29, wherein the housing provides a top connector and a bottom connector for connecting and sealing to a wellhead component located above and below the housing.

31. The blowout preventer of any one of claims 16 to 30, configured as a composite wellhead assembly and further comprising, between a top connector and a bottom connector, one or more of the following wellhead components, in any sequence:
an adapter, a valve, a gate valve, a flow tee, a second blowout preventer, and a polish rod clamp.

32. A ram type blowout preventer, comprising:
a housing forming a central bore extending generally vertically through the housing, and a pair of ram bores extending radially outwardly in opposite directions through the housing and intersecting the central bore;
a steel bodied ram positioned in each of the pair of ram bores to provide opposing rams, the ram having a front end portion, a rear end portion, a top portion and a bottom portion and being adapted for sliding movement in the ram bore between an extended position, with the front end portion extending across the central bore and the rear end portion within the ram bore, and a retracted position within the ram bore, each ram being configured with a front face to seal against the front face of the opposing ram and to accommodate a tubular member or rod, if present in the central bore;
a ram actuating mechanism connected to the rear end portion of the ram for extending and retracting the ram between the extended and retracted positions;
a primary rope packing seal formed on the ram from a first length or loop of rope packing, the primary rope packing seal extending horizontally across the front face, then rearwardly, and then either or both of upwardly over the top portion and downwardly over the bottom portion, at a position rearwardly of the front end portion, the primary rope packing seal being held as a closed loop in, so as to protrude radially outwardly from, a continuous first groove formed in the ram; and the primary rope packing seal extending across the front face of the ram with a vertical offset relative to the primary rope packing seal on the front face of the opposing ram, such that in the extended position, the primary rope packing seals on the opposing rams seal against each other but with the vertical offset;
such that, in the extended position, the primary rope packing seals on the opposing rams seal against each other on opposing front faces, against the tubular member or rod if present, and against the ram bores to seal the central bore.

33. The blowout preventer of claim 32, further comprising a secondary rope packing seal formed on the ram from a second length or loop of rope packing extending across the front face, and being spaced from the primary rope packing seal, the secondary rope packing seal being held in, so as to protrude radially outwardly from, a second groove formed in the ram, wherein the secondary rope packing seal extends horizontally across the front face of the ram with a vertical offset relative to the secondary rope packing seal on the front face of the opposing ram, such that in the extended position, the secondary rope packing seals on the opposing rams seal against each other but with the vertical offset.

34. A ram type blowout preventer, comprising:
a housing forming a central bore extending generally vertically through the housing, and a pair of ram bores extending radially outwardly in opposite directions through the housing and intersecting the central bore;
a steel bodied, full bore ram positioned in each of the pair of ram bores to provide opposing rams, the ram having a front end portion, a rear end portion, a top portion and a bottom portion and being adapted for sliding movement in the ram bore between an extended position, with the front end portion extending across the central bore and the rear end portion within the ram bore, and a retracted position within the ram bore, the ram being configured with a front face to seal against the front face of the opposing ram and to accommodate and seal against tubular member or rod, if present in the central bore;
an actuating mechanism connected to the rear end portion of the ram for extending and retracting the ram between the extended and retracted positions, each ram comprising:
i. a body component forming the bottom portion of the ram, the body component having a front portion, a rear portion, a front end and a rear end;
ii. a seal component forming the top portion of the ram and extending rearwardly of the front end portion of the ram, the seal component having a front portion, a rear portion, a front end, a rear end, and a front face;
iii. the body component having a cut-out in its front portion to provide a seal support surface to support the seal component, the seal support surface being inclined front to rear such the seal component rides upwardly and rearwardly on the seal support surface;

iv. the seal component having an inner surface which generally conforms to the seal support surface of the body component;
v. the body component and seal component combining, in an assembled form, to form the full bore ram, which when out of the extended position has the front end of the seal component forming a leading edge portion which protrudes a horizontal distance beyond the front end of the body component, and which leaves a gap between the rear end of the seal component and the body component; and vi. connectors for connecting the seal component and the body component while allowing the seal component, in the extended position, to be pressed against the seal support surface of the body component and to ride upwardly and rearwardly on the seal support surface; and a primary rope packing seal formed on the seal component of the ram from a first length or loop of rope packing, the primary rope packing seal extending horizontally across the front face of the seal component, rearwardly, and then upwardly over the top portion of the ram at a position rearwardly of the front end portion of the ram, the primary rope packing seal being held as a closed loop in, so as to protrude radially outwardly from, a continuous first groove formed in the seal component;
such that, in the extended position, the primary rope packing seals on the opposing rams seal against each other on opposing front faces, against the tubular member or rod if present, and against the ram bores to seal the central bore.

35. The blowout preventer of claim 34, wherein the primary rope packing seal extends across the front face of the seal component with a vertical offset relative to the primary rope packing seal on the front face of the seal component of the opposing ram, such that in the extended position, the primary rope packing seals on the opposing rams seal against each other but with the vertical offset.

36. The blowout preventer of claim 35, further comprising a secondary rope packing seal formed on the ram from a second length or loop of rope packing extending =

horizontally across the front face of the seal component, and being spaced from the primary rope packing seal, the secondary rope packing seal being held in, so as to protrude radially outwardly from, a second groove formed in the seal component, wherein the secondary rope packing seal extends across the front face of each seal component with a vertical offset relative to the secondary rope packing seal on the front face of the seal component of the opposing ram, such that in the extended position, the secondary rope packing seals on the opposing rams seal against each other but with the vertical offset.

37. The blowout preventer of claim 36, wherein the first groove and the second groove are generally dove-tail shaped in cross section to hold the first or second length or loop of rope packing.

38. The blowout preventer of claim 37, wherein the ram is formed as a blind ram such that the front faces of the opposing rams seal against each other in the extended position to seal the central bore.

39. The blowout preventer of claim 37, wherein the front face of the ram is formed with a vertical groove to accommodate the tubular member or rod.

40. The blowout preventer of any one of claims 32 to 39, wherein:
the first length of rope packing, and the second length of rope packing if present, are formed of a rope packing material in a braided, twisted, woven or knitted form;
the steel bodied ram is formed as a single piece steel bodied ram;
the ram bores are generally cylindrical; and the rams are generally cylindrical.