US2467822A

US2467822A - Well packer

Info

Publication number: US2467822A
Application number: US665256A
Authority: US
Inventors: Wilber H Griffin; Thomas M Ragan
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1946-04-26
Filing date: 1946-04-26
Publication date: 1949-04-19
Anticipated expiration: 1966-04-19

Description

April 19, 1949 w. H, GRIFFIN ET AL 2,467,822

WELL PACKER Fil ed April 26, 1946 VIII/[47112711711112 m 71 1:4352 H GQ/FF/N,

fl/OMAS M RAG/4 1N VENTOR5.

ATTORNEY Patented Apr. 19, 1949 Hagan, Downey, Ualif a'ssi'gnors to Baker 'Oil Tools, Inc, Vernon, Calif., a corporation of California Application April '26, 1946, Serial No.'665, 25'6 This invention rel-ates to well devices, and more particularly to well packers designed to be lowered within well casings, liners and similar well conduits for the performance of desirable functions therein.

Well packers are provided with rubber or rubber-like packing members for eiiectin'g seals between the body members and the walls of well casings or liners in which the packers are to be used. A portion of the packing member is adjacent a retainer, which may have a loose or sliding fit on the packer body. Despite the provision of a relatively small operating clearance between the retaining member and the packer'body, under many well operating conditions involving high pressures, high temperatures, or both, this clearance space afiords a gap through which the packing material may flow. Under some circumstances such material has been almost completely dissipated through the gap and is unavailable 7 Claims. (01. 166-12) by means of which it is lowered through the well casing l2 to the desired setting point. The packer is anchored against movement in an upward direction by a set of upper segmental slips l3 initially held in retracted position by shear screws [4 threaded into a 'oo'nioal-like expander l 5 slidable on the exterior of the body it]. This expander, whose outer surface tapers in an upward and inward direction to conform to the for the continued performance of its function of sealing oii the space between the packer body and wall of the well casing or liner.

It is, accordingly, an object of the present invention to prevent flowing of rubber and similar packing materials through the clearance space existing between a packer body, on which the packing member is mounted, and a packing retainer or abutment surrounding the body.

This invention has other objects that will become apparent from a consideration of the embodiment shown in the drawings accompanying and forming part of the present specification. This iormwill now be described in detail to illustrate the general principles of the invention, but it is to be understood that such detailed description is not to be taken in a limited sense, since the scope of the invention is best defined by the claims appended hereto.

Referring to the drawings:

Figure 1 is a longitudinal section and elevation of a well packer in a well casing, with its parts in retracted position;

Figure 2 is a partial longitudinal section of the well packer anchored in packed oii condition within the casing;

Figure 3 is an enlarged fragmentary section of part of the packer shown in Figure 1; and

Figure 4 is a view similar to Figure 3 of part of the packer in packed off condition.

The invention is disclosed in the drawings as applied to a well packer of the general type shown in United States Patent No. 2,120,151. Essentially, it consists of a central tubular body 10 secured to a string'oi tubing or drill pipe ll,

inner taper on the slips B, is also initially secured to the body by one or more shear screws l6.

Downward movement of the well packer is prevented hy a plurality of segmental lower slips ll having tapered surfaces inclined downwardly and inwardly and adapted to slide along a companion external tapered surface on the exterior of a lower conical expander 18, which is slidably mounted on the body It. The lower slips are initially held in retracted position by shear screws I9 securing them to the lower cone I8, and the lower cone is also held in an initial upward position with respect to the lower slips by one or more shear screws '20 secured to the body I0. The lower screws I9, 20 have a greater shear value than the upper screws 14, It, for reasons hereinafter set forth, and as also explained in the abovepatent.

A packing sleeve 2! is mounted on the body in between the two expanders l5, l8. In the specific example disclosed, this sleeve has external end flanges 2 2, 22 interlocking with inwardly

ex tending flanges

23, 23 on the expander cones. The packing sleeve is also provided with

internal lip seals

24, 24 near its ends, adapted to slidably seal with the external surface of the body.

The upper slips 13, when in retracted position, are contained within the circumferential confines o'i a trip ring 25 secured to the upper end of the body I0. Similarly, the lower slips ll are contained initially within the peripheral confines of an abutment at the lower end of the body, defined by a valve housing and guide 26 threaded on a lower body flange 27. This valve guide depends from the body and has a trip ball seat 28 secured in its lower end by a shear screw 29. An arm 38 extends upwardly from the seat to hold a buoyant back pressure ball valve 3! in ineffective position to one side of the passage through the packer body ill, to prevent its engagement with a valve seat 32 at the lower end of the body while the tool is being lowered through the fluid in the well casing.

The tool is run in the well bore with its parts in retracted position, as shown in Figure 1. When the setting point is reached, a trip ball "33 is lowered or pumped down through the tubular string until it engages the trip ball seat 28, closin the body passage against flow of fluid therethrough. Pressure can then be built up in the tubing string and body to force fluid under pressure through lateral ports 34 in the body into the elastic packing sleeve 2|, inflating the latter against the casing and then elongating it in an upward direction to shear the screws |6, I4 holding the upper expander i5 to the body I and the upper set of slips |3 to this expander. Such upward movement of the conical expander l causes it to move within the slips l3 and force them radially outward along the abuttin trip ring 25 into engagement with the casing (as explained in the aforesaid patent). The tubing string II is then elevated to move the body l0, lower slips H and lower cone l8 upwardly with respect to the upper expander and slips, foreshortening or compressing the packing unit 2| in a longitudinal direction and expanding it outwardly against the casing l2 to form a leak- IJlOOf seal between the body It) and casing l2.

After the packing has been thus engaged with the casing, a continuation of the upward strain and movement of the packer body |0 shears the screws 20, I9 holding the lower expander |8 to the body and the slips I! to the expander, the lower abutment 26, 2! shifting the slips |1 longitudinally in an upward direction along the outer surface of the expander 8 and radially into anchoring engagement with the casing 2. Such action occurs because the upper expander I5 is prevented from moving upwardly by the casing engaging upper slips l3 and sealed off packing 2|. Wickers |3a on the upper slips face in an upward direction and wickers Ila on the lower slips in a downward direction, preventing upward movement of the upper cone l5 and downward movement of the lower cone |8, and also precluding shifting of the intervening packing 2 I.

Upward movement of the packer body Ill is prevented by the anchoring engagement of the upper slips I3 in the wall of the casing I2. Downward movement of the packer body I0 is prevented by an expander locking device, consisting of a plurality of downwardly converging grooves 35 containing locking ball elements 36, in effect forming a one-way clutch. The lock device permits the body I 0 to be moved upwardly with respect to the slips IS, IT, expanders |5, I8 and packing member 2 I, in order to effect complete anchoring in packed off condition of the well packed against the casing, but downward movement of the packing body In thereafter is prevented by the ball locking elements 36 wedging between the exterior of the body l0 and the tapered surfaces of the locking grooves 35. Downward strains imposed on the body are transmitted through the locking balls 36 to the conical expander l8, and through the lower set of slips l1 to the wall of the casing I2.

After the packer has been fully set, additional pressure imposed on the fluid in the tubing string and packer body shears the screw 29 holding the trip ball seat 28 to the guide 26 and blows it from the guide, releasing the back pressure ball valve 3| and permitting it to engage its seat 32, preventing return flow of fluid back into the packer body H).

The need for a sliding action between the conical expanders [5, I8 and the body H) to effect setting of the packer within the well casing requires that the inside diameter of the conical expanders be made slightly greater than the outside diameter of the packer body. The difference in diameters is not very great. For example, well packers of the type described can be produced economically and operated efficiently if the difference in diameters is approximately 0.008 of in inch, which provides a radial clearance or gap of 0.004 of an inch.

In the use of well packers under high temperatures and pressure conditions, as when employed for performing high pressure squeeze cementing operations in hot wells, or as production packers high temperature and pressure well flowing conditions, it has been found that leakage sometimes develops around the packer body I0, apparently caused by flowing of the packing material through spaces or gaps existing between this body and wall of the casing. It has been found that some of the packing material flows, or tends to flow, into and through the relatively small annular clearance space 31 between the packer body l0 and abutment 5 adjacent the packing element 2|. The present invention contemplates the prevention of such cold flowing of packing material.

To accomplish the stated objective, a ring 38 of pliant, inelastic or malleable material, such as ordinary lead, copper, Babbitt metal, etc., is disposed between each of the expander abutments l5, l8, and packing 2| to bridge the clearance space 31 between each abutment and the exterior of the body I0. Each abutment is chamfered adjacent the end of the packing to provide a generally triangular groove 39 in conjunction with the adjacent packing 2| in which a lead, or similar, packing flow preventing annulus or ring 38 is inserted. The outer inclined surface 40 of this ring engages the corresponding chamfered or tapered surface 4| of the abutment, the base 42 of the ring engages the packing 2|, and its inner surface 43 is adapted to engage the exterior of the packer body In.

The ring 38 may also have a working clearance with the packer body In to permit movement of the latter with respect to the conical expander and packing member, in order to effect anchoring of the packer within the well casing. This clearance may equal or be less than the clearance 3'! existing between the expanders l5, I8 themselves and the exterior of the packer body ID.

The lead ring 38, under low pressure operating conditions, functions as an integral part of the expander abutments l5, l8. However, upon the subjection of the packing material to high pressure, high temperatures, or both, it will press the pliant, inelastic ring 38 upwardly along the tapered surface 4| of the abutment and radially inward into firm sealing engagement with the packer body I0, completely closing the small annular clearance space 3! between the abutment and body and precluding any flowing of packing material therethrough. If the pressures are sufliciently high, some of the material 44 from which the ring is made may even be forced into the small annulus 31 between the packer body HI and abutment |5 (see Figure 4). Experience has shown, however, that even under very high pressure conditions, of the order of 7,000 p. s. i., the packing material is incapable of completely removing the lead ring from its bridging position across the clearance space.

The pliant, inelastic ring 38 has such characteristics that it will deform inwardly under the action of the rubber packing element 2| into sealing engagement with the body "I before the rubber element itself can commence squeezing through the small clearance space between the ring and the packer body. As stated above, under low pressure operating conditions the bridging ring 38 need not deform; but it will form a secure bridge across the clearance space under conditions that would otherwise cause the packing material to flow through the clearance space in the absence of the bridging ring.

It is, therefore, apparent that a determination has been made of a leakage difiiculty with the prior art packers and that an effective remedy has been provided for overcoming this undesirable condition. The internal clearance bridging rings do not interfere with the normal setting operations of the well packer, allowing all of the parts to have the required relative sliding movement. It does, however, come into play when needed to close the clearance space between the packer body and the slidable elements therearound. The packing 2| itself produces the sealing and bridging action of the pliant, inelastic or malleable rings 38 between the packer body and the packing abutments l5, l8.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. A well packer, including a packer body, a packing retainer slidable on said body, there being an annular clearance space between said retainer and body, a non-metallic packing around said body adjacent said retainer, and a pliant, inelastic annulus on said body engageable with both said retainer and packing and deformable inwardly by said packing upon its subjection to pressure across said clearance space between said body and retainer.

2. A well packer, including a body, a packer packing retainer slidable on said body, there being an annular clearance space between said retainer and body, a non-metallic packing around said body engaging said retainer, said packing and retainer defining an inner groove therebetween, and a pliant, inelastic annulus in said groove movable by said packing against said retainer and deformable inwardly into engagement with said body to bridge and close said clearance space between said body and retainer.

3. A well packer, including a packer body, a packing retainer slidable on said body, there being an annular clearance space between said retainer and body, a non-metallic packing around said body engaging said retainer, said retainer having an inner beveled surface defining an inner groove in conjunction with said packing, said surface being inclined inwardly in a direction leading away from said packing, and a pliant, inelastic annulus in said groove movable by said packing against the beveled surface of said retainer and deformable radially inwardly into sealing engagement with said body to close said clearance space between said body and retainer.

4. A well packer, including a packer body, a packing retainer movably mounted on said body, there being an annular clearance space between said retainer and body, a non-metallic packing around said body adjacent said retainer, the adiacent surface of said packing being substantially at right angles to the axis of said body, said retainer having an inner beveled surface adjacent said retainer defining a generally triangular groove therebetween, and a pliant, malleable ring in said groove and adapted to be pressed by said packing against said beveled surface and deformed inwardly into sealing engagement with the exterior of said body to close said annular clearance space.

5. In a well packer having a packer body and a plurality of slips adapted to be engaged with the wall of a casing by an expander movably mounted with respect to said body, there being an annular clearance space between said expander and body; the combination therewith of a non-metallic packing adapted to seal said annular space between said body and wall of said casing and having a portion adjacent said expander, and a pliant, malleable ring in said eX- pander adjacent said packing portion and adapted to be deformed inwardly by said packing against said body to bridge the annular space between said expander and body.

6. A well packer having a packer body, upper and lower expanders mounted on and movable with respect to said body, there being respective annular clearance spaces between said expanders and said body, upper and lower sets of slips cooperab-le with said upper and lower expanders, respectively, for anchoring said Well packer to said casing against movement in both longitudinal directions, a non-metallic packing sleeve disposed on said body between said expanders, each of said expanders defining an inner groove in conjunction with said packing sleeve, and a pliant, inelastic ring in each of said grooves adapted to be engaged and deformed inwardly by said packing sleeve against said body to bridge the annular spaces between said expanders and said body.

7. A well packer, including a packer body having a portion with an uninterrupted cylindrical outer surface, a packing retainer slidable on said body, there being an annular clearance space between said retainer and body, a non-metallic packing around said body engaging said retainer, said packing and retainer defining an inner groove therebetween, and a pliant, inelastic annulus in said groove movable by said packing against said retainer and deformable into engagement with said uninterrupted surface of said body portion to bridge and close said annular clearance space between said body and retainer.

WILBER H. GRIFFIN. THOMAS M. RAGAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 785,907 McBride Mar. 28, 1905 1,734,040 McEvoy Nov. 5, 1929 2,135,583 Layne Nov. 8, 1938 2,204 648 Baker June 18, 1940 2,249,171 Quintrell July 15, 1941