US3328040A

US3328040A - Combination stripper and blowout preventer

Info

Publication number: US3328040A
Application number: US353971A
Authority: US
Inventors: Galen C Prichard
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-03-23
Filing date: 1964-03-23
Publication date: 1967-06-27
Anticipated expiration: 1984-06-27

Description

June 27, 1967 G. c. PRICHARD 3,328,040

COMBINATION STRIPPER AND BLOWOUT PREVENTER Filed March 23, 1964 I v INVENTOR. F I G/en C. Pr E/Iard ATTORNEY United States Patent 3,328,040 COMBINATIGN STRIPPER AND BLOWOUT PREVENTER Galen C. Priclrard, 121 Industrial Road, Perryton, Tex. 79070 Filed Mar. 23, 1964, Ser. No. 353,971 8 Claims. '(Cl. 277-73) This invention relates to improvements in oil and gas Well apparatus and more particularly, but not by way of limitation, to a combination stripper and blow-out preventer for utilization during the completion of a well or during servicing or workover operations on a producing Wel-l.

Subsequent to the drilling of an oil or gas Well bore, the well is prepared for production of fluid in the manner best suited to the subsurface conditions. Perhaps the most common completion method comprises the setting of a final string of easing, known as the oil string, which usually extends from the surface of the ground to the top of or through the subsurface producing zone or oil sand. The oil string is usually then cemented in place and perforated in the vicinity of the producing zone in order that the Well fluid may enter the casing, Since the casing normally remains in the well bore for an extended period of time and repair or replacement thereof is expensive, it is the usual practice to insert a tubing string through the casing and suspend the tubing therein in order that the well fluid may flow therethrough to the surface of the well bore. When the normal pressures Within the well bore are insufficient for elevating the fluid through this central tubing, commonly called the flow string, a pump or other means may be supported by the tubing for providing -an artificial lift of the fluid through the tubing. This flow string may be more easily removed from the well bore for repair work than the cemented casing.

In order to conserve steel materials, many well completion operations today utilize relatively small diameter casing for the oil string as compared to the larger casing, and this smaller casing is often referred to as tubing. Of course, in these installations, the flow string is also of a smaller diameter. Since there is frequently excessive pressure within the well bore, it is desirable to provide a packing device, known as a blowout preventer, around the inner tubing or flow string during the installation thereof within the set casing. This substantially precludes the accidental escape of high pressure from the surface of the well. In addition, it is usually desirable to provide a stripper around the flow string for bearing against the outer periphery thereof as the tubing is lowered within the casing.

The flow string and any pumping equipment, or other artificial lift apparatus carried thereby, is subject to deterioration during the production of the well fluid and it often becomes necessary to pull the flow string as well as the pumping equipment from the bore in order to repair or replace portions thereof. During this operation, usually referred to as stripping, it is considered necessary to install a blowout preventer at the surface of the well to preclude loss of fluid due to excessive pressures in the bore. In addition, it is usually necessary to provide a stripper device around the flow string, or sucker rods, or i any other tubing being removed from the well bore during the remedial work or servicing of the well. As a result, it is usually necessary to install at least two tools or devices in connection with this portion of the servicing operation or in the well completion operations, and in many instances, three or four separate tools are required.

The present invention contemplates a novel combination stripper and blowout preventer which may be utilized in both well completion Work and remedial or workover opera-trons. The novel tool may be used in lieu of the three or four tools usually required in these circumstances. The tool comprises a housing which may be secured directly to the well head or other suitable surface connection member and is provided with a plurality of packermembers of a particular inner and outer configuration for packing off the annular space between the flow string and the housing. Means is carried by the housing which may be either mechanically or fluid operated for longitudinally compressing the packing members to as sure an eflicient sealing 'around the flow string, sucker rods, or the like, as well as the ,inner periphery of the housing. The particular configuration of the sealing or packing member is such that the inner periphery thereof will close completely if there is no tubing inserted therethrough, thus providing a sealing off of an open hole, if desired. The inner periphery of the packing members functions to strip the tubing when either putting the tubing in the hole or pulling it out .of the hole. Thus, this one novel tool may be utilized for at least three separate and independent functions, namely as a blowout preventer, a stripper, or as a complete shut-off blowout preventer. The novel combination blowout preventer and stripper is simple and eflicient in operation and economical and durable in construction.

It is an important object of this invention to provide a single tool for an oil well,installation which may be uti lized in lieu of a plurality of conventional tools presently required in certain well bore operations.

It is another object of this invention to provide a combination stripper and blowout preventer having packing members of a particular configuration for efliciently sea-ling the annular space between an outer housing and the flow string, or the like, of a producing well.

Another object of this invention is to provide a novel combination stripper and blow-out preventer for oil or gas wells which may be operated either by fluid power or manually.

Still another object of this invention is to provide a novel tool for utilization with an oil or gas, well to perform a plurality of functions in a single unit.

Other and further objects and advantageous features of the present invention will hereinafter more fully appear in connection with a detailed description of the drawings in which:

FIGURE 1 is an elevational view partly in section depicting a combination stripper and-blowout preventer embodying theinvention.

. FIGURE 2 is a perspective view depicting a general arrangement for fluid operation of the device depicted in FIGURE 1.

Referring to the drawings in detail, reference character 10 generally indicates a combination stripper and blowout preventer device comprising a substantially cylindrical housing or body 12 having a threaded stem portion 14 provided at one end thereof for connection with a well head (not shown) or the like, normally found at an oil or gas Well site. The opposite end 16 of the housing 12 is open for a purpose as will be hereinafter set forth and an outwardly extending circumferential flange 18 is provided on the outer periphery of the housing 12 spaced from the open end 16. A central bore 20 extends longitudinally through the housing 12 and is enlarged at 22 to provide an inwardly directed annular shoulder 24 for supporting a plurality of stacked resilient members generally indicated at 26. A radially extending port 28 is providedin the housing 12 to provide communication between the interior of the bore 20 and the exterior of the housing 12. A suitable threaded connection member or collar 30 may be secured on the outer periphery of the housing 12 in any suitable manner (not shown) and in alignment with the bore 28 for receiving a suitable fitting (not shown) to permit discharge of well fluid from the bore 20 as is well known.

A cylindrical piston 32 is slidably disposed in the open end 16 of the housing 12 and the lower end 34 thereof bears against the uppermost resilient member 26 as clearly shown in FIGURE 1. A follower cap member generally indicated at 36 is slidably [disposed around the piston 32 and comprises an inner sleeve 38 concentrically arranged with an outer sleeve 40 for receiving the piston 32 within the annular space 42 therebetween. The upper end of the piston 32, as shown in FIGURE 1, is provided with an outwardly extending circumferential shoulder 44 whereby the inner periphery of the piston 32 and outer periphery of the flange 44 engages the sidewalls of the annular chamber 42 for guiding any reciprocal movement of the piston 3-2 with respect to the follower 36 as will be hereinafter set forth in detail. It is preferable to provide a plurality of longitudinally spaced annular sealing ring members 46 on the inner periphery of the piston 32 to provide a sealing engagement with the outer periphery of the inner sleeve 38 and a plurality of spaced sealing rings 48 on the outer periphery of the flange 44 for sealing engagement with the inner periphery of the outer sleeve 40. An inwardly directed annular shoulder 50 is provided on the inner periphery of the piston 32 for engaging one end of the inner sleeve 38 in one relative position there between. An annular ring 52 is removably secured to the lower end of the outer sleeve 40 in any well known manner such as by a plurality of threaded stud members 54. The ring 52 is preferably of an outer diameter substantially equal to the outer diameter of the sleeve 40 and an inner diameter of a size for slidable engagement with the outer periphery of the piston 32. The ring 52 provides a stop to engage the flange 44 for limiting the movement of the piston 32 in one direction within the annular chamber 42.

A threaded aperture 56 is provided in the outer sleeve 40 for receiving a suitable fitting member 58 whereby fluid pressure may be injected into the annular chamber 42 as will be hereinafter set forth. In addition, an outwardly extending circumferential flange 60 is provided at the upper end of the follower member 36 and is provided with a plurality of circumferentially spaced apertures (not shown) disposed in substantial alignment with similarly spaced apertures (not shown) provided in the flange 18 of the housing 12. The

flanges

18 and 60 may be interconnected by means of a plurality of spaced stud members 62 extending through the aligned apertures and secured therein by suitable locking nuts 64 and 66 as is well known.

The packing members 26 may be constructed from any suitable resilient material such as rubber, neoprene, or the like, and is provided with a central bore 68 extending therethrough adapted to engage the outer periphery of the tubing string or flow string (not shown) with which the apparatus is being utilized. The bore 68 is enlarged at 70 and the cross-sectional configuration of the enlarged portion 70 is preferably arcuate as clearly shown in the drawings. The outer periphery of the resilient member 26 may be chamfered at both ends as shown in 72 and 74 and an annular recess 76 is provided around the outer periphery of the resilient member 26 preferably substantially centrally disposed between the chamfered

portions

72 and 74. The cross-sectional configuration of the recess 76 is preferably arcuate as shown in FIGURE 1 and the outer periphery of the resilient member 26 disposed between the recess 76 and the

opposite chamfered

72 and 74 is preferably substantially straight for engaging the inner periphery of the housing 12. The relatively long internal bore 68 provides an efficient sealing around the flow string (not shown), sucker rods (not shown), or the like, extending throughout the device 10. The outer periphery of the resilient members 26 provides an efiicient sealing with the housing 12. The bottom and

top surfaces

78 and 80, respectively, of the resilient members 26 as shown in FIGURE 1 are preferably substantially flat whereby a plurality of the packing members 26 may be superimposed within the housing 12. Of course, the lowermost packing member 26 is supported by the shoulder 24 and the uppermost packing 26 is engaged by the piston 32 whereby longitudinal force or pressure may be exerted on the plurality of packing members 26 disposed within the housing 12.

Referring now to FIGURE 2, fluid may be supplied to the annular chamber 42 of the follower member 36 by means of suitable surface equipment as shown diagrammatically herein. A fluid reservoir 80 may be mounted on a suitable base 82 which in turn is installed in the proximity of the apparatus 10 in any well known manner (not shown). Of course, the reservoir 80 and base structure 82 may be separated from the apparatus 10 by as much as fifty feet, if desired, and is not limited to any particular spacing or position with respect to the device 10. A suitable pump 84 may be mounted on the base structure 82 and connected with the reservoir 80 in any well known manner (not shown) for moving the fluid from the reservoir 80 through an outlet conduit 86 which extends from the pump 84 to the fitting 58. The actuation of the pump 84 draws the fluid from the reservoir 80 through the conduit 86 and into the annular chamber 42 of the follower cap 36. The fluid in the chamber 42 acts upon the outer surface 88 on the piston 32 for urging the piston 32 in a direction toward the packing members 26. The downward movement of the piston 32 compresses the packings 26 and the particular configuration of the packings 26 causes the deformation thereof to greatly enhance the sealing between the flow string (not shown) and the inner periphery of the housing 12 as will be hereinafter set forth in detail.

Operation The combination stripper and blowout preventer may be installed around the flow string, sucker rods, or other tubular members in a well bore (not shown) by threaded connection at 14 with the well head (not shown) or the like. With the novel tool 10, utilized in position around the tubing or flow string, particularly tubing of a relatively small outer diameter, the packing members 26 will engage the outer periphery of the flow string and function as a blowout preventer.

Referring now to FIGURE 1, the plunger or piston 32 is depicted in the uppermost position with respect to the follower cap 36. A suitable fluid, such as oil, water, or the like, may be introduced into the annular chamber 42 above the piston 32 by means of the pump 84. As fluid is introduced into the chamber 42, an equal force will be exerted in all directions against the sides of the chamber 42 and the outer end 88 of the piston 32. Since the follower 36 cannot move in an upward direction because of the connection with the flange 18, the force exerted on the piston 32 will urge the piston downwardly against the resilient members 26 to exert a longitudinal pressure thereon. This force exerted on the packings causes the packings to deform in such a manner that the internal bore 68 thereof is urged radially inward into a tight sealing engagement with the outer periphery of the tubing extending therethrough. In addition, the outer periphery of the packings 26 are simultaneously urged radially outwardly to form an efficient sealing engagement with the inner periphery of the housing 12. This is action enhanced by the annular groove 76 provided on the outer periphery of the packing members 26. Even though considerable wear may occur to the packing rings 26, particularly on the inner periphery thereof, an increased longitudinal pressure by the piston 32 will maintain an efficient seal between the housing 12 and flow string to provide a prolonged and etficient life for the packing 26.

Of course, well fluid may enter the casing 12 through the bore 20 and since it cannot move upwardly around the resilient members 26, the well fluid will be directed outwardly through the bore 28 and collar 30 for discharge or accumulation in auxiliary equipment as is well known. When the well tubing or flow String is being pulled from the well bore (not shown), the inner bore 68 of the packing members 26, being relatively long, provide an eflicient stripping of the outer periphery of the tubing. In addition, when the tubing or flow string has been completely removed from the well, the inner bore 68 of the packing members 26 will contract radially inward to completely close the bore upon the application of suflicient fluid pressure in the chamber 42, thus sealing off the open hole.

In the event that it is desired to provide manual operation of the device 10, the piston 32 may be moved downwardly by rotation of the studs 62 extended between the

flanges

18 and 60. In this instance, a hydraulic fluid will be injected into the chamber 42 and sealed therein by either plugging of the aperture 56 or through the use of the fitting 58 which may be of any suitable type for checking any back flow of the fluid or precluding passage of the fluid in reverse direction from the chamber 42. The hydraulic fluid trapped within the annular space 42 will provide a lock between the end 88 of the piston and the closed upper end of the chamber 42 and thus, the downward movement of the cap 36 upon rotation of the studs 62 in the proper direction will be transferred to the piston 32 regardless of position thereof with respect to the inner sleeve 38. It is to be noted that the engagement between the flange 44 and the ring 52 limits the movement of the piston 32 in one direction and engagement of the shoulder 50 with the inner sleeve 38 limits the movement of the piston 32 in an opposite direction.

It has been found that the resilient members 26 provide an efficient seal at pressures up to 6,000 pounds per square inch when utilized as a blowout preventer, It has also been found that the packing members will withstand pressures up to 3,000 pounds per square inch while rotating the flow string through a time period of 24 hours and using only one set of the packers. In addition, the apparatus has been tested and found to withstand pressures up to 3,000 pounds per square inch when the flow string has been removed from the well and the device is being utilized as a complete shut-off blowout preventer.

From the foregoing, it will be apparent that the present invention provides a novel combination stripper and blowout preventer which may be used for eflicient stripping of wire lines, sucker rods, relatively small diameter tubing, or the like, when these rods or tubing member-s are either coming in or going out of a well bore under pressure. Furthermore, the overall structure of the device is such that the upper surface thereof can support the spider or slips when these devices are in use in connection with the well operation. The resilient members function efficiently to perform multiple operations and are particularly designed and contracted to provide a prolonged useful life therefor. The device may be either manually operated or hydraulically operated by remote control, if desired. The novel combination stripper and blowout preventer provides a plurality of functions in a well servicing or well completion operation through the use of a single unit. The novel tool is simple and eflicient in operation and economical and durable in construction.

Changes may be made in the combination and arrangement of parts as heretofore set forth in the specification and shown in the drawings, it being understood that any modification in the precise embodiment of the invention may be made within the scope of the following claims, without departing from the spirit of the invention.

What is claimed is:

1. In a tool of the character described, a housing, resilient means disposed within and supported by the housing, cylindrical piston means slidably disposed within the housing and in engagement with one of said resilient means, and follower means cooperating with the slidable means for urging the slidable means in a direction toward the resilient means to apply pressure thereagainst, said follower means including a pair of spaced cylindrical sleeves for receiving the piston means therebetween, said resilient means being of a configuration whereby the inner and oute-r peripheries thereof expand in opposite radial directions upon the application of said pressure thereagainst.

2. A combination stripper and blowout preventer comprising a housing, a plurality of resilient members supported within the housing, cylindrical plunger means slidably disposed within the housing and in engagement with one of said resilient members, follower means secured to the housing and engageable with the plunger means for urging the plunger in a direction toward the resilient members to apply pressure thereto, said follower member including a pair of spaced cylindrical sleeves for receiving the plunger therebetween, and said resilient members being deformable upon the application of said pressure whereby the inner periphery thereof is urge radially inwardly and the outer periphery thereof simultaneously is urged radially outwardly.

3. A combination stripper and blowout preventer comprising a substantially cylindrical body, an inwardly directed annular shoulder provided on the inner periphery of the body, a plurality of substantially annular resilient members disposed within the body and supported by the shoulder, a substantially cylindrical piston member slidably disposed within the body and in engagement with one of the resilient members, a follower member having a pair of spaced concentric sleeves for receiving the piston therebetween and engageable with the piston member, and means cooperating between the body and the follower member for urging the piston member in a direction toward the resilient members for compression thereof.

4. A combination stripper and blowout preventer as set forth in claim 3 wherein each resilient member comprises a resilient body portion having a substantially straight walled central bore extending therethrough, an enlarged portion provided at one end of the central bore, the outer periphery of the body portion being provided with a substantially centrally disposed annular recess to facilitate deformation of the packing member whereby the inner periphery thereof is urged radially outwardly under compression.

5. A combination stripper and blowout preventer comprising a substantially cylindrical body, an inwardly directed annular shoulder provided on the inner periphery of the body, a plurality of substantially annular packing members disposed within the body and supported by the shoulder, a substantially cylindrical piston member slidably disposed within the body and in engagement with one of the packing members, a follower member engageable with the piston member and comprising a pair of concentrically arranged sleeves having an annular space therebetween for slidably receiving the piston, means for limiting the movement of the piston in opposite longitudinal directions within the annular space, means for inserting a fluid within the annular chamber for acting on one end of the piston, and means cooperating between the :body and the follower member whereby the piston may be urged in a direction toward the packing members by either fluid or manual power for compression thereof.

6. A combination stripper and blowout preventer as set forth in claim 5 wherein each packing member comprises a resilient body port-ion having a substantially straight walled central bore extending therethrough, an enlarged recess portion provided at one end of the central bore, the outer periphery of the body portion being provided with a substantially centrally disposed annular recess to facilitate deformation of the packing member whereby the inner periphery thereof is urged radially inwardly and the outer periphery thereof is urged radially outwardly under compression.

7. A combination stripper and blowout preventer comprising a substantially cylindrical housing, an inwardly directed shoulder provided on the inner periphery of the housing, a plurality of superimposed resilient annular packing members disposed in the housing and supported by the shoulder, a substantially cylindrical piston slidably disposed in the housing and in engagement with the uppermost packing member, a follower member comprising a pair of conentrically arranged sleeve members having an annular space therebetween for slidably receiving one end of the piston member therein, stop mean-s cooperating between the follower member and piston member for limiting the longitudinal movement of the piston with respect to the follower member, sealing means carried by the piston member for sealing against the sidewalls of the annular space, means for injecting a fluid into the annular space for action on the end of the piston disposed therein, an outwardly extending circumferential flange provided on the outer periphery of the housing, a complementary outwardly extending flange provided on the outer periphery of the follower member, and threaded stud means extending between the flanges for securing the follower to the housing whereby the follower will urge the piston in a direction toward the packing member by either fluid or manual power for longitudinal compression of the packing members.

8. A combination stripper and blowout preventer as set forth in claim 7 wherein each packing member comprises a resilient body portion having a substantially straight walled central bore extending therethrough, an enlarged portion provided at one end of the central bore, the outer periphery of the body portion being provided with a substantially centrally disposed annnular recess to facilitate deformation of the packing member whereby the inner periphery thereof is urged radially inwardly and the outer periphery thereof is urged radially outwardly under compression.

References Cited UNITED STATES PATENTS 511,734 12/1893 Hoffstadt 277-105 1,793,916 2/1931 Dykeman 277-208 X 2,243,439 5/1941 Pranger et .al. 277-31 3,013,825 12/1961 Wilson 27 773 3,132,867 5/ 1964 Scaramucci 277-4 X 3,168,320 2/1965 Sneed 1277-110 SAMUEL ROTHBERG, Primary Examiner.

Claims

1. IN A TOOL OF THE CHARACTER DESCRIBED, A HOUSING RESILIENT MEANS DISPOSED WITHIN AND SUPPORTED BY THE HOUSING, CYLINDRICAL PISTON MEANS SLIDABLY DISPOSED WITHIN THE HOUSING AND IN ENGAGEMENT WITH ONE OF SAID RESILIENT MEANS, AND FOLLOWER MEANS COOPERATING WITH THE SLIDABLE MEANS FOR URGING THE SLIDABLE MEANS IN A DIRECTION TOWARD THE RESILIENT MEANS TO APPLY PRESSURE THEREAGAINST, SAID FOLLOWER MEANS INCLUDING A PAIR OF SPACED CYLINDRICAL SLEEVES FOR RECEIVING THE PISTON MEANS THEREBETWEEN, SAID RESILIENT MEANS BEING OF A CONFIGURATION WHEREBY THE INNER AND OUT-