WO1984002374A1

WO1984002374A1 - Flow diverter

Info

Publication number: WO1984002374A1
Application number: PCT/US1983/001936
Authority: WO
Inventors: Julian D Keithahn; Charles D Morrill; Joseph R Roche; Gabriel G Alexander; Larry J Tippit
Original assignee: Hydril Co
Priority date: 1982-12-13
Filing date: 1983-12-12
Publication date: 1984-06-21
Also published as: GB2141766A; EP0128206A1; GB8419061D0; DE3381219D1; EP0128206B1; GB2141766B

Abstract

Flow diverter apparatus having a housing (102) and a piston (106) and annular packer (104) disposed therein. The diverter has passages in the piston (118) and housing (120) walls providing fluid communication between the borehole and a vent line (11). A valve in the vent line is opened before the packer of the apparatus is closed about a tubular member in the bore of the apparatus or completely closes the vertical flow path of the bore of the apparatus when no object is therein, thereby diverting pressurized borehole fluid away from the rig equipment and personnel.

Description

FLOW DIVERTER

- 1 This invention generally relates to oil well diverter apparatus and systems , and more particularly to apparatus and systems for redirecting the flow of drilling fluid or mud and cuttings that would oterhwise be blown upward to the rig floor where unbalanced well bore pressures are encountered during initial hole drilling. In general, the apparatus and system according to the invention may be used beneath the drilling floor of any land or marine drilling rig but in particular, the invention finds application with floating drilling equipment.

When drilling an oil or gas well, an initial large diameter bore hole is established to shallow depths. Protective drive conduit or conductor pipe, typically thirty (30) inches ( 76.2 cm) in diameter, is secured in the shallow bore through which the drilling takes place. For offshore drilling, a subsea riser extends from the sea floor to the marine drilling platform. Flow diverters are typically provided below the rig floor and between the conductor conduit and the rotary table of the drilling rig for the purpose of safely venting unbalanced well bore pressure which may produce an upward flow of drilling fluid in the conduit having sufficient impetus to issue from the top of the conduit thereby contributing a hazard to personnel and equipment. Such an occurrence, called a "kick", typically of formation gas accumulations in the fluid of the conduit is often encountered in top hole drilling making a flow diverter essential before blowout preventers are connected to the drilling system, especially for offshore applications. A flow diverter is con sidered necessary for safe operation on a floating offshore drilling rig where blowout preventers are placed on the sea floor only after the casing has been set to a depth, usually several hundred feet below the sea floor. Prior diverter systems have been primarily of two types. The first includes a flow diverter assembly requiring different diameter packing inserts to accommodate different diameter tubular members. Such diverter systems are unable to accomplish complete shut off on open hole. The second has included an annular blowout preventer placed above the vent line in which a valve is disposed to an open condition only when the annular blowout preventer is closed about the drill pipe or other object in the well bore in response to a kick in the annulus of the bore hole.

In the first type of flow diverters, packer elements must be changed for different size tubulars used during drilling and must be removed during tripping of the bottom hole assembly. Such a task is rigorous drudgery to the rig personnel. The well bore is in general left unprotected when there is no object in the well bore because the diverter is not able to close on open hole.

In the second type of flow diverter system the combined height of the annular blowout preventer and of the side outlets of the vent line below the annular blowout preventer may require excessive head room under the rig floor.

For both types of systems which have been provided in the past, significant safety problem has arisen due to the requirement of opening an external valve in the vent line and closing the valve leading typically to the shale shaker of the drilling rig fluid system. In the past, such valves have often been closed by rig personnel while testing the flow diverter, but after the flow diverter has been made operational during drilling, the ex ternal valves inadvertently have been allowed to remain closed. On occasion, the control system elements have been inadvertently incorrectly connected resulting in simultaneous closure of all of the diverter system valves and the diverter itself. If the prior flow diverters have closed about the annulus of a drill pipe or other object in the well bore, such flow diverter systems have created an extremely dangerous situation, and in fact in some cases they have exploded with the result of loss of life and property.

It is generally desired herein to provide a diverting system which is failsafe; that is, when a kick occurs during drilling of a shallow hole well before a blowout preventer has been provided, that kick cannot be accidently confined by the flow diverter apparatus itself to build pressure and explode, even if controls are misconnected or malfunctioning.

The present invention therefore provides a flow diverter adapted for installation below the rotary table of a drilling rig and for the connection above a drilling conduit comprising, the flow diverter including a housing having at least one outlet passage provided in its wall, a packing element disposed within the housing, and annular piston means adapted for moving from a first position to a second position, whereby in the first position the piston means wall prevents interior fluid from communicating with the outlet passage in the housing wall and in the second position the piston means wall does not prevent fluid communication of interior fluid with the outlet passage and urges the annular packing element to close about an object extending through the bore of the housing.

One of the features of the invention is that no insert packers are required in the flow diverter to be changed for different size tubulars, thereby saving rig time, drudgery and operational decisions on the rig floor and in which flow may safely be diverted at any time, even when no object is in the diverter bore.

Another advantageous feature of the present invention is that while it provides apparatus for sealing objects extending through the well bore of varying diameters tor even completely close the well bore where no object is in the well bore) it also eliminates the heed for vent line placement belcw the diverter apparatus. A further aspect of the invention involves the provision of an extremely simple, safe systan without external valves, operators, linkages and controls as well as one which can be easily installed below the drilling rig floor.

It is a further feature of the invention to provide a flow diverting apparatus which, on the occurrence of a kick in the annulus of a drilling conduit, may be caused to close the flow line to the drilling fluid system, to open a vent line for diverting drilling fluid away from the rig and to close the annulus of the bore about a drilling pipe or other object in the conduit or on open hole.

In a preferred aspect of the invention not only is the opening of a vent line and the closing of the line to the rig drilling fluid system accomplished but also the vertical flow path of the bore is completely closed in the absence of pipe or other object in the bore.

A further preferred aspect of the invention involves the provision of a complete integral system requiring but one operation to achieve closing of the flow line to the rig drilling fluid system, opening of an overhead vent line and closing the vertical flow path of the annulus of the bore.

Another preferred feature of the invention involves the provision of means for assuring automatic alignment of the flew diverter apparatus below a permanently installed housing, vent line and flow line.

A further preferred aspect of the invention involves a system which on command safely and automatically opens a vent line and closes a flow line to the rig drilling fluid system before the annulus of the bore hole is closed. is closed.

Further features and advantages of the invention will become more apparent by reference to the accompanying drawings illustrating preferred embodiments of the invention and wherein:

Figure 1 illustrates a prior art flow diverter system in which an annular blowout preventer is placed above a vent line above a conventional conductor pipe; Figure 2 illustrates a first preferred embodiment of flow diverter apparatus according to the invention having passages for fluid communication from the bore hole to outlet holes in the housing wall;

Figure 3 illustrates the flow diverter apparatus of Figure 2 in a closed position having its packing element closed about a tubular member in the bore hole; and

Figure 4 illustrates the flow diverter apparatus of Figure 2 with a vent line and valve connected to the outlet holes in its housing.

Figure 5 illustrates a drilling rig of a floating drill ship, barge or semi-submersible to which a second preferred embodiment of diverting apparatus according to the invention is attached beneath the rig floor and above drilling conduit extending to the subsea surface; Figure 6 illustrates the second preferred form of the flow diverting apparatus of Figure 5 in place within a housing and connected to vent and flow lines where the housing and vent lines are fixed beneath a drilling rig floor; Figure 7 illustrates the flow diverting apparatus of Fig. 6 in which an annular packing element has been closed about a pipe in the bore of the apparatus and in which a vent line has been opened and a flow line has been closed; Figure 8 illustrates an alignment key according to the invention by which the flow diverter may be inserted into a permanent housing and aligned angularly with respect to the permanent housing;

Figure 8A illustrates in more detail the alignment key shown in Figure 8;

Figures 9 through 14 illustrate in various views and cross-sections a seal used to seal about an opening in the apparatus extending to either the vent line or flow line of the invention; Figures 15A and 15B illustrate a third alternative embodiment of the flow diverter in which two pistons are provided, a first piston serving to open and close the vent and flow lines, the second piston serving to urge the annular packing element radially inwardly and alternative, and sequencing means for insuring that the first piston moves before the second piston moves up;

Figures 16A and 16B show a fourth embodiment of the flow diverter in which two pistons are used to insure that the flow line to the shale shaker is closed and the vent line provided to flow pressurized fluid away from the drilling rig floor is open before the annular packing unit is closed about a pipe or other object in the bore hole;

Figure 17A illustrates a fifth embodiment of the flow diverter apparatus in which a single piston serves to not only close the annular packing unit but also to simultaneously close the flow line and open the vent line before the packing unit may be closed; and

Figures 17B and 17C illustrate the single piston diverter of Figure 17A having a single opening to the vent line, a flow line to the rig fluid system being provided above the diverter.

Figure 1 illustrates a prior art installation of an annular blowout preventer 10 used as a diverter in conjunction with a vent or "blowdown" line 11 and valve 20 for use during the drilling of the shallow portion of an oil or gas well. The purpose of the diverter apparatus is to divert pressurized flow in the annulus between the conductor conduit 14 and drill pipe 24 away from the rig and its personnel. The annular blowout preventer 10 is attached directly to the conduit 14 below the rig floor 16. One or more vent lines 11 are connected directly below the annular blowout preventer 10 and are sized to prevent excessive well bore back pressure buildup. A drilling spool 18 is provided to connect the vent line 11 and the annular blowout preventer 10 to conductor pipe 14. A kelly 22 is shown connected to drill pipe 24 either of which may extend through the bore of the annular blowout preventer 10. Flow line 26 provides normal return flow of drilling fluid which is pumped through the kelly 22 through drill pipe 24 to the drilling bit and up the annulus between the borehole or conductor pipe and the drill pipe 24. Flow line 26 empties into a mud tank, shale shaker, etc. to complete the drilling fluid circuit.

Valve 20 has typically been provided as a full opening valve and is controlled via switch 28 which applies opening pressure to valve 20 as closing pressure is applied to blowout preventer 10. Operating pressure for the valves is provided by means of accumulator unit 30.

Figure 1 illustrates the flow diverter apparatus 100 according to the invention. Cylindrical housing 102 is provided for packing element 104 and piston 106. Cylindrical tube 108 is connected to housing 102 and has openings 110 for fluid communication between the bore 112 in diverter apparatus and the annulus 111 between the housing 102 and tube 108. Closing chamber 114 is provided for application of pressurized control fluid in order to urge piston 106 upwardly thereby closing packing element 104 about tubular or other objects 24 in the open ing 112 or for completely closing off the bore 112. Opening chamber 116 is provided to return piston 106 to its normal position and to open packing element 104.

Passages 118 are provided in piston wall 106 for providing fluid communication of the borehole fluid in the annular space between the housing 102 and tube 108. The passages 118 terminate in outlet holes 120 which advantageously are oblong in shape so as to reduce as much as possible the vertical dimension of the flow diverter apparatus 100. Cover 122 about housing wall 102 provides a fluid passageway from outlet hole 120 to vent line 11. Dimension L is provided for the housing of the diverter 100 so that it may be conveniently lowered through the opening of the rotary table to cover mounting framework 126 and attached cover 122 and vent line 11 which are preferably previously mounted below the drilling rig floor. Seals 124 are disposed in grooves about the housing wall for preventing fluid from leaking about the housing wall of the flow diverter apparatus. Figure 3 illustrates flow diverter apparatus

100 where piston 106 has been urged upwardly thereby causing packing element 104 to seal about tubular member 24. Borehole fluid is in communication with holes 120 via passages 118. Figure 4 illustrates the flow diverter apparatus

100 connected to valve 20. Switch 28 opens valve 20 as hydraulic fluid is applied to diverter 100 for closing the packing element.

Thus, the flow diverter apparatus 100 is shorter in vertical height than that of the prior art. The flow diverter apparauts 100 according to the invention therefore enjoys compactness of installation and provides an annular packing element which is adapted to close not only on any tubular in the borehole but also on open hole.

Figure 5 illustrates a drilling rig 220 of a floating drill ship, barge or semi-submersible 221. A sec ond embodiment of a flow diverter in accordance with the invention shown generally at 222 and is provided below the drilling rig 220 is in a permanently installed housing 224 which is mounted below the rotary table 228 of the drilling rig 220. The diverter 222 is connected to a drilling conduit 230, in this case a ball or flex joint for connecting to a riser inner barrel 232. Typically in a drilling system of a floating vessel, a telescopic joint 234 allows for the heave, surge and sway of the vessel and riser joints 236 extend to the sea floor at which a well head member 238 is provided above a thirty (30) inch (76.2 cm) conduit 240 into the earth's surface.

It should be emphasized that while the preferred environment in which the flow diverter and system according to the invention are illustrated is with marine drilling from a floating vessel, the invention may also be used for marine drilling from a bottom supported platform or for land drilling from a land based rig. Figure 5 also illustrates a vent line means 242 and a flow line means 243 which may be permanently provided and fixed to the housing 224. The connection of the flow diverter 222 to housing 224 and vent line and flow line means will be described in detail below.

Turning now to Figure 6 , the preferred form of this second embodiment of a flow diverter and system according to the invention is disclosed. The diverter 222 is shown in place within a housing 224 which is mounted below the rig floor 244 in which the bore 246 of diverter 222 is in line with the bore of the rotary table 228. The width of the diverter 222 is advantageously designed so that it may be lowered through the rotary table into engagement with permanently affixed housing 224. Housing 224 is fixed with respect to the rig floor 244 by means of I beams 246 which are attached by support members 247 as illustrated. Diverter 222 comprises a generally cylindrical body 250 in which an annular packing element 252 is disposed in its upper part. The diverter includes a base 254 the upper part of which partially supports annular packing element 252. An annular space between the base 254 and the outer body 250, is provided to contain a first piston, outer valve sleeve 256, and a second piston, annular piston 258. Annular piston 258 is generally of the kind used in annular blowout preventers. The upper part 310 of piston 258 is in the shape of a conical bowl for engaging the packing element 252 in a conventional fashion. Head 260 forms the top part of the flow diverter and is connected to body 250 by means of studs 262. A spacer or wear ring 264 confines the packing element 252 within the flow diverter housing.

The flow diverter according to the invention fits within the bore of permanently mounted housing 224 and is attached by means of a latching mechanism thereto, such as multi-shouldered dogs 266 which engage complementary grooves in the diverter body 250. The dogs 266 are driven by a piston 268 and rod 270. A latch port 272 is provided for applying pressurized hydraulic fluid behind the piston 268 to drive dog 266 into engagement with the diverter body 250. An unlatch port 274 is provided for driving piston 268 away from the diverter body thereby unlatching the dogs 266. Advantageously, the area of the piston 268 on its latch side 269 is smaller than on its unlatch side 269' to facilitate unlatching even where the dogs have been jammed or stuck. Flow lines are permanently mounted with housing 224 according to the invention. Vent line means 280 and drilling fluid flow line means 282 are shown permanently attached to the housing 224, the attachment being, for example, by welds 283, but the flow line means may be attached advantageously by bolting or other attaching means. The vent line means 280 extends away from the drilling rig such that when the diverter opens the bore of the drilling conduit to the vent line, pressurized drilling fluid may be vented away from the drilling rig and, in the case of a drilling vessel, may be directed to the leeward side of the vessel. The flow line means 282 is preferably directed to the drilling fluid system of the drilling rig, most likely to the shale shaker, where drilling cuttings which have been washed by the drilling fluid are removed from the fluid and where the fluid may be re-entered into the drilling system in conventional fashion.

According to the invention, the first piston or valve sleeve256 is provided with two passages or holes 284 and 286 provided in its wall. Likewise, the annular piston 258 has two holes 288 and 290 provided in its wall as illustrated in Figure 6. In addition, holes 292 and 294 are provided in the wall of the base 254. Likewise, holes 296 and 298 are provided in the body wall 250 of the diverter and, after insertion in housing 224 , are in alignment with the vent line means 280 and the flow line means 282.

Figure 6 illustrates the flow diverter according to the invention in its normal state during which drilling operations are conducted through its bore and in which the return of the drilling fluid via the annulus is conducted. The bore of the diverter is provided for fluid communication with the bore of the drilling conduit attached beneath the diverter 222 as illustrated in Figure 5. Drilling fluid is returned to the drilling rig "mud" or fluid system via the hole 294 in the base, the hole 290 in the annular piston and thence through the hole 286 in the annular sleeve 256 and the hole 298 in the wall of the body for fluid communication through the flow line means to the drilling rig fluid system. On the other hand, the upper part 300 of the valve sleeve 256 covers the hole 296 provided in the body 250 such that no drilling fluid from the interior of the diverter is allowed to communicate with the vent line means 280. Thus, during normal drilling operations the annular packer 252 is in its normal relaxed position leaving an annular space between any pipe or object and the bore of the diverter and fluid communication exists between the bore of the diverter and the flow line means 282.

Hydraulic fluid conduit 302 is connected to a source (not shown) of pressurized hydraulic control fluid via a port 304 for applying pressurized hydraulic fluid beneath valve sleeve piston 256 and annular piston 258. During a "kick", an operator may open port 304 to the source of pressurized hydraulic fluid wherein the pressurized fluid is applied to region 306 beneath the valve sleeve 256 and the annular piston 258.

According to the invention, the valve sleeve 256 is caused to move in an upward axial direction before the annular piston 258, because more area is provided underneath valve sleeve 256 than is provided under annular piston 258, because of the opposing effect of the annular packing element 252 on the conical bowl portion 310 of annular piston 258 and because it has less mass relative to annular piston 258 opposing the motion. During a kick, hydraulic fluid under valve sleeve 256 and annular piston 258 drives valve sleeve 256 upward whereby the hole 286 in valve sleeve 256 is driven upwardly and out of alignment with the hole 298 in the body wall. Simultaneously, hole 284 in the wall of valve sleeve 256 is driven upwardly and into alignment with hole 296 in the wall of the body 250.

The annular piston 258 begins to move after the valve sleeve 256 and in so doing the upper conical bowl portion 310 of piston 258 forces the packing element 252 radially inwardly. As valve sleeve 256 moves upwardly, the upper surface 311 of the sleeve 256 is a apted to engage with downward facing shoulder 312 on the conical bowl portion 310 of piston 258 providing additional upward force to piston 258 until valve sleeve reaches its maximum upward travel. Piston 258 continues to move upwardly until the annulus between a drill pipe or other object in the well bore and the bore of the diverter is closed off.

Figure 7 illustrates the diverter after the annular piston 258 and the valve sleeve 256 have moved to their "actuated" positions and have caused annular packing element 252 to close about pipe 312 in the bore of the diverter. Hole 284 of valve sleeve 256 has moved into alignment with hole 296 allowing fluid communication via hole 292 provided in the base of the diverter and the hole 288 provided in the annular piston 258 wall. Any pressurized drilling fluid in the bore of the diverter is safely diverted away from the drilling rig via vent line means 282. Hole 288 is sufficiently large that flow between the bore of the body via hole 292 is not prevented when piston 258 moves upwardly. The lower part 314 of valve sleeve 256 is shown in Figure 7 covering the hole 298 which is in alignment with the flow line means 282, thereby preventing further fluid communication between the bore of the diverter and the flow line means 282 to the drilling fluid system. Closing of the flow line means 282 thereby prevents the flow of possibly highly combustible, pressurized drilling fluid to the rig drilling fluid system. For the case of a floating drilling rig, the fluid system may be in a confined part of the drilling vessel and could create an extremely hazardous condition if the flow of drilling fluid pressurized with gas from an underground formation is not terminated as quickly as possible.

As best shown in Figure 6 , another feature of the invention includes a means by which the valve sleeve 256 is prevented from failing to close the flow line means 282 and to open the vent line means 280 during kick. A ring 314 provided in the lower part of the annular piston 258 is provided for engagement with an annular shoulder 316 of valve sleeve 256. If the valve sleeve 256 were to become stuck and fail to move upwardly on the application of hydraulic fluid beneath its area 306, the ring 314 of piston 254 on its upward movement would engage the shoulder 316, thereby forcing the valve sleeve 316 upwardly. The ring 314 would force sleeve 256 upward until hole 284 becomes aligned with hole 296 thereby opening the bore of the diverter to the vent line means 296 and simultaneously causing the lower part of the valve sleeve 256 to cover hole 298 in the bore of the diverter thereby preventing further fluid communication to the drilling rig fluid system.

Means are provided to return the flow diverter to its normal position after any emergency has been corrected. Hydraulic line 320 is provided via port 322 for connection to a source of pressurized hydraulic control fluid to an area 326 above a shoulder provided in the bottom of the valve sleeve 256. When hydraulic fluid via port 304 is removed, application of pressurized hydraulic fluid via port 322 drives valve sleeve 256 downwardly to its normal position. Shoulder 316 in engagement with ring 314 forces annular piston 258 downwardly to its rest or normal position.

A plurality of sealing means are provided to contain either pressurized hydraulic fluid under the valve sleeve 256 and annular piston 258 or to seal about other openings and holes in the pistons and body walls. For example, sealing means 321 and 322 prevent pressurized hydraulic fluid beneath valve sleeve 256 from escaping into the interior of the diverter. Likewise, valve sealing means 324 and 326 seal against loss of hydraulic fluid be neath annular piston 258. Sealing means 330. and 332 provide sealing for the upper conical bowl section 310 of annular piston 258 as it moves upwardly for forcing annular packing element radially inward. Integral seals 340 are provided on the wall 250 of the diverter 222 for sealing the wall 250 of the diverter against the wall of the permanent housing 224 and also for providing a seal with the valve sleeve 256 as it moves across the openings 296 and 298 in the wall of the body. Turning now to Figure 8 which shows a portion of a cross-section through the line 8-8 shown in Figure 6, means are provided for aligning the diverter 222 within the permanently mounted housing 224. As discussed earlier, the diverter is adapted to be lowered by the drilling rig travelling block through the rotary table and into the bore of housing 224. Means are provided for aligning the diverter 222 both axially and angularly such that the holes 296 and 298 are in alignment with the permanently mounted vent line means 280 and the flow line means 282 which are permanently attached to the housing 224. Axial alignment is achieved by providing an inwardly facing annular shoulder 350 in the permanent housing 224 and a complementary outwardly facing shoulder 351. Engagement of the complementary shoulders 350 and 351 causes the diverter to come to rest at the proper axial or vertical alignment within the housing 224.

Angular alignment is accomplished by means of an alignment key 360 extending through the wall 250, the valve sleeve 256 and the annular piston 258 into engagement with base 254. The head 362 of the key 360 partially extends outwardly from the wall 250 for engagement into an axial slot 364 provided in a portion of the wall of housing 224. The key 360 serves to prevent angu lar rotation of valve sleeve 256 and annular piston 258 thereby insuring that the holes 284 and 286 of the valve sleeve 256 and the holes 288 and 290 of the annular piston 258 do not move out of angular alignment once the diverter is in place within the permanent housing 224. The outward extension of the head 362 of key 360 fitting within the slot 364 insures that the diverter 222 is aligned angularly with respect to housing 224 such that the hole 296 in the body wall is in alignment with the vent line means 280 and the hole 298 is in alignment with the flow line means 282. Slot 364 in the housing provides the means by which the head extension 362 insures the angular alignment.

Slot 365 illustrated in Figure 8A is provided in the key 360 so that drilling fluid within the annular space extending between the holes 292 and 294 of the base 254 and holes 288 and 290 of the annular piston 258 is not impeded from moving up or down by the key itself, but rather may move freely through the key. As may best be seen again in Figures 2 and 3, the hydraulic fluid ports 304 and 322 are also aligned with openings 370 and 372 in the body 250 of the diverter 222 when the alignment key head 362 fits within alignment slot 364 of the permanent housing 224, Sealing means 388 and 382 provide a seal about the hydraulic fluid opening 370 while seal means 384 and 386 seal about the opening 372 with respect to the permanent housing 224 wall. Thus, there is provided according to the invention a means by which the diverter 222 is easily aligned both axially and angularly such that passages in the body wall of the diverter are aligned with the vent line and flow line means and with the hydraulic ports for operating the diverter.

Returning again to Figure 6 , the position of key 360 is seen when the diverter is in a normal, not actuated condition. The slots 390 and 392 illustrate the slots in the first piston or valve sleeve 256 and second piston or annular piston 258 which, allow the sleeve and piston to move with respect to the fixed key 360. Figure 7 illustrates the position of key 360 as the valve sleeve 256 and annular piston 258 have been moved upwardly during an emergency situation.

Illustrated in Figure 6 is an outwardly extending annular space 400 which is provided to accept a test tool, thereby simulating a test pipe or other object extending through the bore of the housing about which the annular packing unit 252 may be closed in order to test the operation of the diverter.

Figures 9 through 14 illustrate the integral seal 340 provided in the wall 250 of the diverter 222. The seal is adapted to be affixed within the wall about the opening 296 or the opening 298 in the body wall. Advantageously, the holes 296 and 298 are oblong on the interior of the body wall while circular on the exterior of the wall. The purpose for providing such a passage through the body wall is to miminize the height of the hole in the interior of the body wall while maintaining a maximum area of the outlet passage so as not to hinder significantly the flow therethrough thereby preventing creation of potentially hazardous back pressure during emergency venting. It is advantageous to provide according to the invention, an outlet passage of minimum height in the interior of the wall of the diverter so that less axial upward movement of the valve sleeve 256 is required to either open or close the hole. On the other hand, the vent line means 280 and the flow line means 282 normally are cylindrical tubular members having a circular opening, thereby requiring that the outlet on the exterior wall of the diverter be circular in shape. Thus, an integral sealing member 340 is provided about the opening in the body wall which, is advantageously provided to seal against the permanent housing on the exterior of the diverter wall and against the valve sleeve 256 movement on the interior of the diverter wall. Preferably, the seal is embodied in a molded or cast member which may be easily manufactured obviating the necessity of machining two unusually shaped holes in each diverter housing which are costly and relatively difficult to machine. Thus, sealing member 340 is preferably an integral member of elastomeric material and preferably has a support member embedded therein to give it strength. Alternatively, sealing member 340 may be an integral member fabricated from non-elastomer materials. For example, it maty be cast steel, ceramic or a composite material.

Figure 9 illustrates the seal member as viewed from its exterior side showing the opening 341 on its outside being circular in nature and showing the interior oblong hole 342 Exterior sealing rings 343 are shown for sealing the permanent housing 342 against the exterior of the body diverter.

Figure 12 shows the sealing element as viewed from the inside of the diverter snowing the interior opening 342 being of oblong shape in which the height of the opening is less than its width. The exterior circular opening 341 is also illustrated. Interior sealing ridge 344 is provided for sealing against the valve sleeve 256 as it either comes into alignment with the opening 342 or seals the opening with an upper part of the sleeve where the vent line means is covered or the lower part of the piston where the flow line means is covered. Sealing shoulder 345 is provided for sealing the seal assembly 340 to the housing wall 250.

Figure 10 illustrates the shape of the seal element when viewed from its side in which the oblong open ing 342 is shown as well as the circular opening 341. Advantageously, a metallic support member 390 is provided in the seal element 340 and extends completely about the warped surface defined by the member connecting the circulax opening 341 with the tablong opening 342.

Figures 13 and 14 illustrate in cross-section how the support element 390 is preferably disposed within the sealing element itself.

Figures 15A and 15B show a further alternative embodiment of the flow diverter according to the invention. Figure 15A shows the flow diverter in its normal or relaxed state. Figure 15B shows it in the activated or diverting state. Flow diverter222' is shown within permanently fixed housing224 having a flow line means 282 and a vent line means 280 affixed to the housing. The diverter 222' has a body 250 and a base member 254'. The holes 296 and 298 are provided in the body wall for alignment with the vent line means 280 and the flow line means 282. A valve sleeve 256 ' and an annular piston 258' are provided in addition to the annular packing element 252 in the upper part of the diverter 222' . Holes are provided in the valve sleeve 256' and annular piston 258' similar iio tfhat shown in the second embodiment of the invention shown in Figure 6, but alternative sequencing means are provided for insuring that the valve sleeve 256' moves upwardly for closing the hole 298 to the flow line means and opening the hole 296 to the vent line means before the piston 258' is enabled to force the annular packing element 252 about a pipe or other object in the well bore or complete shut off on open hole. The sequencing means includes means for connecting a source of pressurized hydraulic pressure via conduit 500 initially solely under the valve sleeve 256'. As the valve sleeve moves upwardly and comes to a final po sition such that the lower part of valve sleeve 256' covers hole 298 and the hole 284' in the wall of the valve sleeve comes into alignment with the vent line means 280, a port 502 becomes uncovered, allowing the pressurized hydraulic fluid to be provided under the annular piston 258' thereby driving it upwardly and caus ng annular packing element 252 to close about a pipe or other object in the well bore or to completely close the annulus of the well bore in the absence of an object in the bore. A check valve 503 is provided such that when pressurized hydraulic fluid is provided in conduit 505 in order to force the valve sleeve 236' downwardly, the downward movement of annular piston 258' forces hydraulic fluid down through conduit 506 and check valve 503 thereby relieving the pressure under annular piston 258'.

Figures 16A and 16B illustrate another alternative embodiment of the diverter according to the invention. Figure 16A shows the diverter in its rest state; Figure 16B shows the diverter in the diverting state with the packing element closing about the bore with no object therein. Again the diverter 222 is adapted to fit within the bore of a permanently fixed housing 224 below the rig floor of a drilling rig and above a drilling conduit. Flow line means 282 and vent line means 280 are provided fox connection respectively to the drilling fluid system and for conducting pressurized fluid away from the drilling rig during an emergency. As shown in Figure 16A, two pistons are provided by which a first piston 600 is has two holes provided in its wall. Hole 605 is normally in alignment with the flow line means 282 while hole 602 is normally below the opening 603 in the wall of the diverter 222.

A second piston 610 is provided generally above the first piston 600 for engagement with the packing element 222. The means by which the sequencing of the first piston is forced upwardly before the second piston 610 is enabled to engage the packing element 222 is embodied by the upper head 621 of the first piston adapted for engagement with a lower shoulder 622 provided genexally under the second piston 610. As a source of hydraulic pressure via conduit 620 is applied beneath the first piston 600, it is forced generally upward thereby closing hole 601 with a portion of the piston 600 below a hole in its wall 605. Hole 602 in the first piston wall 600 moves upward into alignment with the hole 603 provided opposite the vent line means 280. A point is reached where the head 621 of the first piston 600 comes into engagement with the downward facing shoulder 622 of the second piston 610 whereby further upward movement of piston 600 is transmitted via piston 610 to annular packing element 222 forcing it radially inward for closing about a pipe or other object disposed in the bore therein.

Figure 16B illustrates the diverter in the closed position where the packing element has completely closed about the bore of the diverter. The first piston 600 has moved upwardly such that the flow line means 282 has been closed and the vent line means 280 has been opened. Means for returning the pistons of the diverter to their normal position is provided via conduit 623 through which a source of pressurized hydraulic control fluid forces the first piston 600 back to its normal state. Piston 610 returns to its normal state because of gravity and because the packing element acts to return it to its relaxed state. Thus, as shown in Figure 12A and 12B, a mechanical means is provided for insuring that the pistons 600 and 610 sequence in operation such that the annulus of the diverter is not closed before the flow line means is closed and the vent line means is opened. Figure 17A illustrates another embodiment of the flow diverter 222 in which a single piston 700 is provided not only for closing the annular packing element 252 about an object in the bore of the diverter but also for closing a flow line means 282 and opening a vent line means 280 during an emergency. The single piston 700 has an upper conical bowl portion 702 adapted for engagement with the packing element 252 and forcing it radially inward as the piston 700 moves axially upward. A hole 710 in the piston wall is normally in alignment with a hole 712 in the body 250 of the diverter 222. The second hole 713 in the body wall, provided in alignment with the vent line means 280, is covered by the piston 700 wall when the diverter is in its normal state. When a source of high pressure hydraulic fluid is provided beneath the piston 700 via conduit 720, piston 700 is forced upward thereby opening vent line means 280 via hole 713 providing fluid communication with the bore of the housing 222. As piston 700 moves up, hole 712 in the body wall becomes covered by the lower part 725 of piston 700, and ultimately, hole 712 becomes completely covered by the lower part 725 of the piston.

Means are provided for insuring that the packing element 252 does not close about a pipe or other object in the bore hole before hole 712 is covered and hole 713 is opened by providing a space 730 above the packing element through which the packing element is free to move axially upward without being forced radially inward as the upper conical portion 702 of the piston 700 moves up. Thus, a means is provided by which the vent line means 280 is opened and the flow line means 282 is closed from fluid communication with the bore of the flow diverter 222 before the annular packing element 252 is enabled to fully close about a pipe or other object in the bore hole or to completely close the bore of the diver ter 222 in the absence of an object in the bore. Alternatively, as illustrated in Figure 17B, the flow line means 282 may not be provided in the wall of the piston at all, there being provided a flow line means 282' above the diverter through which the flow is normally directed to the fluid system of the drilling rig. For that arrangement, a single passage such as hole 713 of Figure 13A to the vent line means is provided which is normally covered by the piston 700. The packing element serves to close all fluid communication to the flow line means, the vent line means serving to divert the flow of pressurized drilling fluid as the piston moves upwardly.

Figure 17C illustrates an alternative embodiment of the diverter illustrated in Figure 17A where piston 700 is required to move upward before hole 713' provided in body 250 is opened.

Thus, there has been described various embodiments of a diverter adapted for insertion into a permanently fixed housing connected to a drilling rig. The diverter, in a single apparatus, provides a substantially failsafe means for closing the bore of a drilling doncuit to which the diverter is attached and for closing the flow line to the drilling fluid system of the rig and opening a vent line for diverting pressurized drilling fluid away from the drilling rig. Means have been provided to insure that the vent line is opened and the flow line to the shale shaker is closed before the annular packing element closes the annulus of the bore about a pipe or other object in the well. Sealing means by which the holes in the wall of the diverter are sealed interiorly to a piston moving past the hole and exteriorly to the permanent housing are also disclosed.

The flow diverter according to the invention is failsafe in that it eliminates the need for external valves in the vent line downstream of the connection of the vent line to the permanent housing of the diverter. Such valves, as indicated in the background section above, have been the source of negligence and failure when used with prior diverting systems, causing loss of property and injury to personnel.

Claims

CLAIMS 1. Apparatus (100) adapted for use as a flow diverter for directing pressurized well bore fluid of a well bore away from a drilling rig via a diverter vent line (11), characterized by a cylindrical bousing (102) having one or more outlet passages (120) provided in its wall, the outlet passages (120) connected for fluid communication with the diverter vent line (11) , a packer (104) in the housing (102) baving an annulus of resilient material, a packer-actuating piston (106) in fluid communication with the borehole (112) within the housing (102) and engaged with the packer (104) and Actuatable to apply radially inwardly directed pressure to the packer for sealing with a pipe (24) or other object in the well bore or for closing the well bore in the absence of any object in the well bore, the piston (106) having one or more passages (118) for fluid communication between the borehole (112) and the outlet passage (120) provided in the housing wall.

2. Apparatus (100) for directing pressurized well bore fluid of a well bore away from a drilling rig comprising, said apparatus being characterized by a cylindrical housing (102) baving one or more outlet passages (120) provided in its wall, a packer (104) in the bousing (102) having an annulus of resilient material; a packer-actuating piston (106) in fluid communication with the borehole (112) within the housing (102) and engaged with the packer (104) and actuatable to apply radially inwardly directed force to the packer for sealing with a pipe (24) or other object in the well bore or to close same in the absence of any object in the well bore, the piston (106) having one or more passages (118) for fluid communication between the borehole (112) and the outlet passage (120) provided in the housing wall, and flow line means (20, 26) connected to said housing (102) for diverting fluid from said housing outlet passage (120) away from the borehole (112) .

3. Apparatus according to Claim 2, characterized by cylindrical tube means (108) disposed coaxially within the bousing (102) and having openings (110) for providing fluid communication between the fluid in the well bore and the annulus between the tube means (108) and the housing (102), said packer-actuating piston (106) being disposed in said annulus between the tube means (108) and the housing (102) for engagement with the packer (104) the passages (118) in said piston (106) being in fluid communication between the fluid in the tube means/housing annulus and the outlet passage (120) provided in the bousing wall.

4. The apparatus of Claim 2 or 3, characterized in that said outlet passages (120) in the cylindrical housing (102) terminate in outlet holes in the wall of the housing, the holes being oblong.

5. The apparatus of Claim 2 or 3, characterized in that said flow line means comprises a flow line (26) connected to said housing outlet passage (120) , and valve means (20) in said flow line (26) operable for opening said flow line (26) before borehole fluid pressure exceeds an unsafe limit.

6. A flow diverter (222) adapted for installation below the rotary table of a drilling rig and for connection above a drilling conduit characterized by a housing (224) having at least one cutlet passage (296, 298) provided in its wall, a packing element (252) disposed within the housing (224) , and annular piston means (256, 258; 800) adapted for moving from a first position to a second position, whereby in the first position the piston means wall (300) prevents interior fluid from communicating with the outlet passage (296) in the housing wall and in the second position the piston means wall (300) does not prevent fluid communication of interior fluid with the outlet passage (296) and urges the annular packing element (252) to close about an object extending through the bore of the housing (224) .

7. The apparatus of claim 6, characterized by means for preventing the packing element from sealing with a pipe or other object in the well bore or closing the vertical flow path of the well bore in the absence of any object in the well bore until the piston means wall does not prevent fluid communication of interior fluid with the outlet passage.

8. The apparatus of claim 6 as adapted for diverting pressurized well bore fluid in the drilling conduit away from the rig (220) and sealing the annulus between a pipe or other object and the conduit or closing the vertical flow path of conduit in the absence of any object in the conduit, characterized in that said packing element (252) has an annulus of resilient material, said apparatus including means (280) for connecting the outlet passage (296) in the housing wall (224) to a vent line (242) for diverting fluid away from the drilling rig (220) and said piston means (256, 258; 700) in fluid communication with the drilling fluid within tbe housing (224) for preventing fluid communication between the well bore and the vent line (242) when the piston means (256, 258; 700) is not actuated, and for applying radially inwardly directed force to the packer (252) for sealing with the pipe or other object in the well bore (246) or to dose the vertical flow path of the well bore (246) in the absence of any object in the well bore (246) and allowing fluid communication between the well bore (246) and the vent line (242) when the piston means (256, 258; 700) is actuated.

9. The apparatus of claim 8, characterized in that said housing (224) is cylindrical, and further comprising seal means (340) for sealing between the well bore (246) and the outlet passage (296) in the wall of the cylindrical housing (224) when said piston means (256, 258; 700) is not actuated.

10. The apparatus of claim 9, characterized in that the bottom of the piston means (256, 258; 700) engages an annular shoulder of the housing (224), and the seal means is disposed between the annular housing shoulder and the bottom of the piston means (256, 258; 700).

11. The apparatus of claim 8, characterized in that when said piston (256, 258; 700) is not actuated, the piston wall (300) covers the outlet passaere (296) in the housing (224) , and the seal means is disposed between the housing and the piston wall below the outlet passage.

12. The apparatus of claim 8 characterized by at least one additional outlet passage (298) provided in the housing wall, a hole in the piston wall disposed so that the hole in the piston wall is substantially aligned with the additional outlet passage 298 in the housing wall when the piston is not actuated, and means for connecting the additional outlet passage to a flow line means in fluid communication with the drilling rig drilling fluid system, whereby as the piston is actuated to apply radially inwardly directed force to the packing element, the piston moves axially upward within the housing, un covering the hole connectable to a vent line for diverting fluid away from the drilling rig, and covering the hole connectable to a flow line directed to the drilling rig drilling fluid system.

13. Apparatus (222) adapted for connection to a drilling conduit beneath a drilling rig floor for diverting pressurized well bore fluid in the conduit away from the rig (220) and sealing the annular space between a drill pipe or other object and the conduit or closing the vertical flow path in the bore of the conduit in the absence of any object in the conduit, characterized by a bousing (224) having at least one outlet passage provided in its wall, means (280) for connecting said outlet passage (296) in the housing wall to a vent line (242) for diverting fluid away from the drilling rig (220) , a packing element (252) in the housing (224) having an annulus of resilient material, annular piston means (256, 258; 700) within the housing (224) and in fluid communication with the conduit and engageable with the packing element (252) actuating means for urging the piston means (256, 258; 700) axially upward within the housing (224) thereby applying radially inwardly directed force to the packing element (232) for sealing with a pipe or other object in the well bore (246) or for closing the vertical flow path in the well bore in the absence of any object in the well bore (246) , a bole (284) in the piston wall disposed axially below the outlet passage in the housing wall before the actuating means urges the piston means axially upward, whereby, as the piston means is urged axially upward, the hole (284) in the piston wall becomes aligned with the outlet passage (296) in the housing wall thereby providing a fluid communication path from the interior of the piston means to the vent line (242) for diverting well bore fluid in the conduit away from the rig (220) as the piston forces the annular packing element (252) to close about pipe or other objects in the bore thereof or to completely close the bore in the absence of any object therein.

14. The apparatus of claim 13, characterized in that said bousing (224) has a central Bore (246) in communication with the bore of the conduit and having first and second holes (296, 298) provided in its wall, said first hole comprising the outlet passage (296) in the housing and means (282) for connecting the second hole (298) in the housing to a flow line means (243) in fluid communication with the rig drilling fluid system, the piston means bole comprising a first bole in the piston means wall disposed axially below the first hole (284) in the bousing wall, the piston means wall (300) axially above the first piston hole (284) covering the first hole in the housing wall before the actuating means urges the piston axially upward, and a second hole (286) in the piston means wall disposed in alignment with the second hole (298) in the housing wall before the actuating means urges the piston means axially upward, thereby providing a fluid communication path from the interior of the piston to the flow line (243) to the rig drilling fluid system, whereby, after the piston means is urged axially upward, the first hole (284) in the piston means wall is aligned with the first hole (290) in the bousing wall thereby providing a fluid communication path from the interior of the piston means to the vent line (242) for diverting fluid away from the drilling rig (220) , and where the second hole (286) in the piston means wall is moved out of alignment to a position above the second hole (298) in the housing wall, the piston means wall (314) axially below the second piston means hole (286) covers the second hole (298) in the housing wall, and the packing element (252) seals with a pipe or other object in the well bore (246) or closes the vertical flow path in the well bore in the absence of any object in the well bore.

15. The apparatus cf claim 14, characterized by means for preventing the packing element (252) from sealing with a pipe or other object in the vertical flow path of the well bore (246) or closing the well bore in the absence of any object in the well bore until the piston means wall (314) covers the second hole (298) in the housing wall.

16. The apparatus of claim 15, characterized in that the preventing means comprises the second hole (286) in the piston means being of oblong shape.

17. The apparatus of claim 15, characterized in that the preventing means comprises a space (730) between the packing element (252) and an upper plate through which the packing is relatively free to move axially upward as it is initially engaged by the annular piston means (700).

18. A flow diverting system for diverting pressurized well bore fluid in a drilling conduit away from a drilling rig (220) which has a rotary table mounted upon a support structure, characterized in that the system includes a support member mounted to said support structure beneath said rotary table (228) and having a bore therethrough, a vent line means (242) fixed to said support member (224) for diverting fluid away from the drilling rig (220) , and flow diverting apparatus (222) having, a housing (224) with a bore (246) therethrough in communication with the conduit and having at least one outlet passage (296) provided in its wall, means for supporting the housing within the bore of the support member, means (280) for sealingly connecting the outlet passage (296) in the housing wall with the vent line means (242) fixed to the support member, a packer (252) in the housing having an annulus of resilient material, annular piston means (256, 258; 700) in fluid communication with the bore through the housing and engaged with the packer (252) , actuating means for urging the pis ton means axially upward within the housing thereby applying radially inwardly directed force to the packer for sealing with a pipe or other object in the well bore or to close the vertical flow patb of the well bore in the absence of any object in the weil bore, whereby, when said piston means is not actuated, tbe piston means covers the outlet passage in the housing wall thereby preventing fluid communication between the interior of the piston and the vent line means, and when said piston means is actuated, the piston means uncovers the outlet passage in the housing wall allowing fluid communication between the interior of the piston means and vent line means.

19. The system of claim 18, characterized by seal means (340) for sealing between the interior of the piston means (256, 258; 700) and the outlet passage

(296) in the wall of the housing (224) when the piston means is not actuated.

20. The system of claim 19, characterized in that the bottom of the piston means (256, 258; 700) engages an annular shoulder of the housing, (224) and the seal means (340) is disposed between the annular housing shoulder and the bottom of the piston.

21. The system of claim 19, characterized in that when the piston means (256, 258; 700) is not actuated, the piston wall (300) covers the outlet passage

(296) in the housing (224), and the seal means (340) is disposed between the housing (224) and the piston means wall below the outlet passage.

22. The system of claim 18, characterized by a second outlet passage (298) in the wall of the housing (224), a flow line means (243) fixed to the support member in fluid communication with the drilling rig mud system, a hole (286) in the piston means wall disposed in alignment with the second outlet passage (298) in the housing wall before the actuating means urges the piston axially upward, whereby as the piston means is urged axially upward to apply radially inwardly directed force to the packer, tbe second outlet passage in the wall of the housing is covered by the piston wall below the bole in the piston, thereby interrupting fluid communication between the interior of the piston and the second flow line means.

23. A flow diverter (222) adapted for installation below the rotary table (228) of a drilling rig (220) and for connection above a drilling conduit (230) , characterized by, a bousing (224) having a body portion with a generally vertical bore (246) therethrough, and having at least one outlet passage (296) provided in the wall of the body, the body adapted for connection above the drilling conduit (230) , an annular packing element (252) disposed within the housing (224) , first annular piston laeans (256) adapted for moving from a first position to a second position, whereby in tbe first position tbe first annular piston means (256) prevents drilling fluid in the interior of the housing (224) from communicating with the outlet passage (296) in the housing wall, and in the second position the first annular piston means (256) does not prevent fluid communication of interior drilling fluid with the outlet passage (296) , second annular piston means (258) disposed in the housing (224) for urging the annular packing element (252) to close about an object extending through the bore (246) of the bousing (224) , while moving from a third position to a fourth position in the bousing (224) , first actuating means (302) for urging said first annular piston (256) from said first position to said second position, second actuating means (312) for urging said second annular piston (258) from said third position to said fourth position, said first and second actuating means (302, 312) cooperatively adapted to begin movement of the first piston (256) from the first position to the second position before said second piston (258) begins to move from the third position to the fourth position.

24. The flow diverter of claim 23 characterized in that the first actuating means is a hydraulic circuit means (302) for providing pressurized hydraulic fluid to the first annular piston means (256) , and the second actuating means comprises the bead (311) of the first piston means (256) adapted for engagement with a shoulder (312) of the second piston means (258) after the first piston is urged upwardly by the first actuating means.

25. The flow diverter of claim 24 wherein the first and second piston means (311, 312) are arranged in tbe body portion of the bousing (324) whereby the outlet passage (296) provided in the wall of the body is at least partially in fluid communication with the vertical bore (246) of the body before the packing element (252) closes about an object in the bore (246) .

26. The flow diverter of claim 25, wherein the first annular piston means comprises an annular piston (256) having a hole (284) in its wall, wherein in the first position an upper part (300) of the piston (256) covers the outlet passage (296) provided in the wall of the body and in the second position the hole (284) in the wall of tbe annular piston (256) is in substantial alignment with the outlet passage (298) provided in the body wall.

27. A flow diverter (222) adapted for installation below the rotary table (228) of a drilling rig (220) and for connection above a drilling conduit (230) characterized by, a housing (224) having a body portion with a generally vertical bore (246) therethrough and baving first and second outlet passages (296, 298) provided in the wall of the body, the body being adapted for connection above the drilling conduit (230) , an annular packing element (252) disposed within the housing (224), a first annular piston (256) disposed within the housing (224) , having first and second holes (284, 286) in its wall, the piston adapted for movement from a first position to a second position, where in tbe first position the first outlet passage (296) in the wall body is covered by a portion (300) of the first piston (256) above the first hole (284) in the piston wall, and the second hole (286) in the piston wall is in substantial alignment with the second passage (298) provided in the wall body, and where in the second position the first hole (284) in the piston wall is in substantial alignment with the first hole (296) in the wall body, and the second outlet passage (298) in the wall body is covered by a portion (314) of the first piston (256) below the second hole (286) in the piston wall, and a second annular piston (258) disposed within the housing (224) and adapted for upward movement in the housing and urging of the annular packing element (252) to close about an object extending through the bore (246) of the housing, and means (302, 312) for upwardly moving the first and second pistons (256 , 258) whereby the second piston (258) is prevented from sufficiently urging tbe packing element (252) into sealing engagement with a pipe or other object in tbe well bore (246) until the first piston (256) moves to a position where the second hole (286) is covered by the piston wall (314) extending below the second hole (286) in the piston wall.

28. The flow diverter of claim 26 characterized in that the first outlet passage (296) is adapted for connection to an overboard vent line (242) and the second outlet passage (298) is adapted for connection to a drilling fluid system.

29. The flow diverter of claim 26 characterized in that the means for upwardly moving the first and second pistons (256, 258) comprises, a hydraulic circuit means (302) for providing pressurized hydraulic fluid to at least a portion of the first piston (256) , an engagement shoulder (312) on the second piston (258) adapted for engagement with the head (311) of the first piston (256) , and an axial separation between the head (311) of the first piston (256) and the shoulder (312) of the second piston (256) whereby solely the first piston is moved upwardly by the hydraulic circuit means (302) for a distance equal to the axial separation, the separation being sufficient for the second hole (286) in the first piston (258) to move axially upwardly until the piston wall portion (314) below the second hole (286) covers the second hole (286) in the wall body before the second piston (258) causes the packing element (256) to be in sealing engagement with a pipe or other object in the wall bore (246) .

30. The flow diverter of claim 28 characterized in that the first hole (284) in the first piston (256) is at least partially aligned with the hole (284) in the housing wall before the second piston (258) causes the packing element (252) to be in sealing engagement with a pipe or other object in the well bore (246) .

31. A flow diverter (22) characterized by, a housing (324) having a body portion with a generally vertical bore (340) therethrough, and having first and second outlet passages (296,298) provided in the wall of the body, the body adapted for connection above the drilling conduit (230), an annular packing element (252) disposed within the housing (324) ,

first and second annular piston (256,258) concentrically disposed within the housing (324) , the first annular piston (256) adapted for axial movement between first and second positions and having first and second holes (284,286) provided in its wall, whereby at the first position the first hole (284) of the first piston (256) is below the first outlet passage (296) of the body wall and an upper part (300) of the piston (256) covers the first outlet passage (296) of the body wall, and the second hole (286) of the first piston (256) is in substantial alignment with the second outlet passage (298) in the body wall, and at the second position (256) of the first piston (256) , the first hole (284) of the first piston is in substantial alignment with the first cutlet passage (296) provided in the body wall, and the second hole (286) of the first piston (256) is above the second outlet passage (298) of the body wall and the lower part (214) of the piston below the second hole (286) covers the second outlet passage (298) of the body wall, the second annular piston (258) adapted for engagement with the annular packing element (252) and axial movement between third and fourth positions whereby the second piston (258) urges the annular packing element (257) radially inward toward annular sealing with a pipe or other object in the bore (246) of the housing (224) as the second annular piston (258) moves from the third position to the fourth positi,on, actuating means (302) for urging the first and second pistons (256,258) axially upward and sequencing means for urging the first piston (256) axially upward and for closing the second outlet passage (298) of the body wall and for opening the first outlet passage (296) of the body wall before the second piston (258) is urged axially upward to force the annular packing element (252) to seal with a pipe or other object in the bore (246) of the housing (224).

32. The diverter of claim 31 characterized in that the actuating means (302) comprises a source of pressurized hydraulic fluid provided under both the first piston (256) and the second piston (258) .

33. The diverter of claim 32 characterized in that the sequencing means includes the larger actuating area under the bottom of the first piston (256) than under the bottom of the second piston (258), the larger mass provided for the second piston (258) than that of the first piston (258) and the engagement of the second piston (251) with the annular packing element (252) , whereby in response to the actuating means the first piston (256) moves relatively quickly upward and the second piston (258) moves relatively slowly upward.

34. The diverter of claim 33 characterized in that the actuating means further includes engaging means comprising the cooperative engagement of the upper part (311) of the first piston (256) with a shoulder(312) of the second piston (258) for providing additional upward force to the second piston after the first piston has moved upwardly.

35. The diverter of claim 33 characterized by safety means for causing the first piston to move axially upward with the second piston if said first piston fails to move axially upward upon the application of pressurized hydraulic fluid under both, the first piston and the second piston and the second piston moves axially upward before the first piston does so.

36. The diverter of claim 35 characterized in that the safety means comprises an outwardly extending shoe (314) attached near the bottom of the second piston (258) in cooperation with an inwardly facing shoulder(316) near the bottom of the first piston (258) .

37. The diverter of claim 32 characterized by deactuating means (326) for deactuating the actuating means (302) and urging the first piston (256) back to its first position and the second piston (258) back to its third position.

38. The diverter of claim 31 characterized in that the first and second pistons (256,258) are disposed in an annular space between the outer wall of the body (250) and an interior annular base member and wherein the base member (254) has at least two openings (292,294). one each generally aligned with the first and second outlet passages (296,298) in the body wall.

39. The diverter of claim 31 characterized in that the first and second outlet passages (296,298) in the body wall are oblong in shape on the inside of the body wall, the oblong shape characterized by being greater in width than in height, and generally circular on the outside of the body (250).

40. The diverter of claim 39 characterized by integral seal means (340) one each inserted in the body wall about each of the outlet passages (296,298) in the body wall, said seal means for sealing against the first annular piston (256) walls and for sealing against a permanent housing (224) to which the diverter (222) may be inserted.

41. A flow diverter (222) adapted for installation below the rotary table (228) of a drilling rig (220) and for connection above a drilling conduit (230) , said diverter being characterized by a housing (224) having a body portion (250) with a generally vertical bore (246) therethrough, and having first and second passages (292,294) provided in the wall of the body (250), the body (250) adapted for connection above the drilling conduit (230), an annular packing element (252) disposed within the housing, first and second annular pistons (256' ,258') concentrically disposed within the housing (224), the first annular piston (256') being adapted for axial movement between first and second positions and having first and second holes (284' ,285') provided in its wall, whereby at the first position the first hole (284') of the first piston (256') is below the first outlet passage (296) of the body wall. and an upper part of the piston (256') is above the first hole (284') and the first outlet passage (296) of the body wall, and the second hole (286') of the first piston (256') is in substantial alignment with the second outlet passage (298) provided in the body wall, and the second hole of the first piston (256) is above the second outlet passage of the body wall and the lower part of the piston below the second hole covers the second outlet passage of the body wall, the second annular piston (258') being adapted for engagement with the annular packing element (252) and axial movement between third and fourth positions whereby the second piston (258') urges the annular packing element (252) radially toward annular sealing with a pipe or other object in the bore (246) of the housing as the second annular piston (258')moves from the third position to the fourth position, actuating means for urging the first piston (256') axially upward from the first position to the second position and the second piston (258') is urged axially upward from the third position to a fourth position suffi cient to force the annular packing element (252) to seal with a pipe or other object in the bore of the housing or to close the vertical flow path of the bore of the housing where the first annular piston (256') is urged from the first position to the second

42. The flow diverter of claim 41 characterized in that the second annular piston (258') is disposed interiorly to the first annular piston (256') for at least a portion of its axial extent, the second annular piston (258') having at least two holes provided in its wall for fluid communication between the interior of the body (250) and the first and second outlet passages

(296, 298) in the body wall not covered by a portion of the wall of the first piston (256') .

43. The flow diverter of claim 41 characterized in that the actuating means comprises a source of pressurized hydraulic fluid, first means (500) for directing the pressurized hydraulic fluid under the first piston, and second means (502) for directing the fluid under the first piston (250 ') additionally under the second piston (258') only after the first piston has moved axially upward from the first position to the second position.

44. The flow diverter of claim 43 characterized in that the second directly means is a conduit means (502) embedded in the body (250) of the housing, the conduit means (502) covered by the wall of the first piston

(256') and uncovered only if the first piston moves to the second position thereby allowing hydraulic fluid communication between the piston chamber under the first piston with the piston chamber under the second piston

(258').

45. The flow diverter of claim 44, characterized by means (505) for urging the first piston (256') from the second position to the first position and means (303) for relieving pressurized hydraulic fluid under the second piston (258') in order to return the second piston from a fourth position to the third position.

46. A flow diverting system for diverting pressurized well bore fluid in a drilling conduit (230) away from a drilling rig (220) having a rotary table (228) mounted upon a support structure, said system being characterized by a support housing member (224) mounted to the support structure beneath the rotary table (228) and having a bore therethrough, a vent line means (242) fixed to the support housing member (224) for diverting fluid away from the drilling rig (220), a flow line means (243) fixed to the support housing member (224) and in fluid communication with the drilling rig mud system, and flow diverting apparatus (222) having, a diverter housing having a body portion (250) with a generally vertical bore (246) therethrough, and having first and second outlet passages (292, 294) provided in the wall of the body (250) , the body (250) adapted for connection above the drilling conduit (230) , means for supporting the diverter housing (250) within the bore of the support housing member (224) , means (280) for sealingly connecting the first outlet passage (296) in the housing wall with the vent line means (242), means (282) for sealingly connecting the second outlet passage (298) in the housing wall with the flow line means (243) , an annular packing element (252) disposed with the housing (224) , first and second annular pistons (256, 258) concentrically disposed within the diverter housing, the first annular piston (256) being adapted for axial movement between first and second positions and having first and second holes (284, 286) provided in its wall, whereby at the first postion of the first piston (256) the first hole (284) is below the first outlet passage (296) of the body wall and an upper part (300) of the piston (256) is above the first hole (286) and covers the first outlet passage (296) of the body wall, and the second hole (286) of the first piston (256) is in substantial alignment with the second outlet passage (298) in the body wall, and at the second position of the first piston (256) , the first hole (284) of the first piston (256) is in substantial alignment with the first outlet passage (296) provided in the body wall, and the second hole (286) of the first piston (256) is above the second outlet passage (298) of the body wall and the lower part (314) of the piston (256) below the second hole (286) covers the second outlet passage (248) of the body wall, the second annular piston (258) being adapted for engagement with the annular packing element (252) and axial movement between third and fourth positions whereby the second piston (258) urges the annular packing element (257) radially inward toward annular sealing with a pipe or other object in the bore (246) of the housing (224) as the second annular piston (258) moves from the third position to the fourth position, actuating means (302) for urging the first and second pistons (256, 258) axially upward, and sequencing means for urging the first piston axially upward and to close the second outlet passage (298) of the body wall and to open the first outlet passage (296) of the body wall before the second piston (258) is urged axially upward to force the annular packing element (252) to seal with a pipe or other object in the bore (246) of the housing (224) whereby the flow line means (243) to the drilling rig mud system is closed and the vent line means (242) directing fluid away from the drilling rig (220) is open before the annular packing element (252) seals the annulus about a pipe or other object in the diverter housing bore (246) .

47. The system of claim 46, characterized by integral seal means (340) one each inserted in the body wall about each of the outlet passages (296, 298) in the body wall, said seal means for sealing against the first annular piston (256) walls and for sealing against the support housing member (224).

48. The system of claim 46, characterized in that the first and second outlet passages (296, 298) in the body wall are oblong in shape on the inside of the body wall, the oblong shape characterized by being greater in width than in height, and generally circular on the outside of the body.

49. The system of claim 46, characterized in that the means for supporting the diverter housing within the permanent housing member (224) comprises dog means (266) mounted in the wall of the support housing (224) adapted for releasable latching engagement with recess means in the wall of the diverter housing

(250) .

50. The system of claim 46, characterized by means (350, 351) for aligning the diverter housing within the support housing (224) wherein the first and second outlet passages (296, 298) in the wall of the body (250) of the diverter housing are aligned axially and angularly respectively to the vent line means (242) and the flow line means (243) fixed to the support housing (224) .

51. The system of claim 50 characterized in that the first and second pistons (256, 258) are disposed in an annular space between the outer wall of the diverter housing body (250) and an interior annular base member (254) and wherein the base member (254) has at least two openings (292, 294) one each generally aligned with the first and second outlet passages (296, 298) in the body wall.

52. The flow diverter system of claim 50, characterized in that the aligning means comprises an inwardly facing landing shoulder (350) provided in the bore of the support housing member (224) and a cooperating outwardly facing landing shoulder (351) provided in the body (250) of the diverter housing, the axial distance between the landing shoulder of the support housing to the center of the flow line (243) and vent line means (242) having the same axial distance between the landing shoulder of the diverter housing to the center of the respective outlet passage openings in the body wall of the diverter housing, whereby the diverter housing is supported within the support housing (224) having first outlet passage aligned axially with the vent line means and the flow line means, and an angular alignment key (360) provided through the wall of the body (250) of the diverter housing and extending through axial slots (364) of the first and second pistons (256, 258) into the base member (254) whereby the pistons (256, 258) are angularly constrained from moving, the angular alignment key having a head portion (362) fixed to the outer wall of the diverter housing, the head portion (362) extending outwardly from the wall of the diverter (222) and a cooperating axial recess (364) in the inner wall of the support housing (224), the width of the recess (364) being substantially the same as the width of the outwardly extending head portion (362) of the diverter alignment key (360) , the angular distance between the head of the alignment key to the first and second outlet passages (296, 298) being substantially the same as the angular distance between the axial recess (364) in the support housing (224) and the vent line means (243) and the flow line means (245), whereby the diverter housing is supported within the support housing with its outlet passages (296, 298) aligned angularly with the vent line means (242) and the flow line means (243) .

53. The system of claim 49, characterized in that the alignment key (360) has a slot (365) provided axially along its extent adapted to allow the purpose of drilling fluid so as not to impede the movement of said first and second pistons (256, 258).