US 3575238 A
Description (OCR text may contain errors)
United States Patent 2,671,510 3/1954 Slick et a1. 166/187 2,741,313 4/1956 Bagnell 166/187 2,942,669 6/1960 Mounce et al. 166/187 3,032,116 5/1962 Barry 166/187 3,134,441 5/1964 Barry et a]. 166/187 Primary ExaminerJames A. Leppink AttorneyRobert K. Rhea ABSTRACT: An elongated tubular body, connected with a well string in a borehole, telescopically receives a centrally bored mandrel having an annular flange forming a piston slidable in a fluid containing reservoir formed between the wall of the body and mandrel. A dilatable and collapsible member surrounding and connected to the body intermediate its ends defines an inflation chamber communicating with the fluid reservoir. Spring means, surrounding the tubular mandrel, normally urges the mandrel and body in telescopic extended relation.
PATENTED APR20 1971 NVEN To/a HAROLD E. SH i LLANDER INFLATABLE PACKED BACKGROUND OF THE INVENTION 1. Field of the invention.
The present invention relates to inflatable devices and more particularly to an inflatable packer for oil wells, or the like.
Inflatable packers are used in the oil well industry for forming a seal between the pipe string and wall of the casing or borehole to seal off formation zones and for various other purposes well understood in the oil industry.
The principal advantage of the inflatable packer over a conventional solid rubber or resilient material type packer is the ability to expand to a relatively larger diameter; form a seal with an irregular borehole wall surface; and withstand higher pressure differential without a flowing" of the packer material.
2. Description of the Prior Art.
Some of the inflatable packers, as shown by the prior art, utilize the fluid in the well inside or outside of the well string or within the casing to inflate the packer. This is accomplished by interrupting the circulation of fluid through the well string to build up a differential pressure by a pump at the well surface so that a valve, closed, as for example, by dropping a ball down the well string, actuates the packer for inflation by the fluid.
Other prior art packers employ a downhole hydraulic pump having an independent reservoir of fluid wherein the pump is actuated for expanding the packer by manipulating the pipe string.
The most pertinent devices shown by the prior art include the US. Iats. No. 2,741,313 to Bagnell; No. 2,633,200 to Irlumason and No. 3,032,1l6 to Barry.
This invention eliminates the necessity of valve means for initiating and releasing the packing action and is accomplished by longitudinal telescoping movement of its components operating a closed hydraulic system.
SUMMARY OF THE INVENTION An elongated sleevelike body is connected with a well string in a borehole. An elongated tubular mandrel is slidably received and secured within the body. An annular flange, on the mandrel, forms a piston slidable within a fluid containing reservoir between the wall of the body and mandrel. A dilatable member longitudinally surrounds and is connected with a portion of the body to form an inflation chamber.
Spring means surrounds the mandrel below the body and normally urges the mandrel and body in extended telescopic relation.
The principal object of this invention is to provide an inflatable packer for connection with a well string in a borehole and means for expanding and collapsing the packer by telescopic movement of its components.
BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS Like characters of reference designate like parts in those FIGS. of the drawings in which they occur.
In the drawings:
The reference numeral It) indicates the device, as a whole, which is cylindrical in general configuration adapted to be connected with a well string 12 and run into a borehole indicated by the casing 14. The device 10 includes a sleevelike body portion I6 threadedly connected at its upper end with a tool joint 18 in turn threadedly engaged with the well string I2. An elongated tubular mandrel 20 is telescopingly received by its upper end portion by the inner wall surface 22 forming the bore of the body 16. The bore 24 of the mandrel 20 is substantially equal to the bore 26 of the tool joint 18 and forms a continuation of the flow passage, not shown, of the well string I2. The depending end portion of the body is circumferentially enlarged to form a cylindrical wall portion 28 surrounding the mandrel 20 in spaced relation therewith to form a fluid containing reservoir 30 and define an annular body shoulder 32. The mandrel 20 is provided with an annular flange 34 forming a pistonlike portion slidably contacting the inner surface of the wall 28. A lock ring 36, loosely surrounding the mandrel below the flange 34, is threadedly engaged with the depending end of the wall 28 to maintain the mandrel within the body 16.
A dilatable and collapsible packer element 38, formed of reinforced resilient material, such as rubber or the like, surrounds an intermediate portion of the body above its shoulder 32 and is secured thereto by inserting one end portion of the member 38 into an annular groove 40 formed in the shoulder 32. The other end of the member 38 is similarly secured within an annular groove 42 formed in a collarlike ring 44 slidably surrounding the periphery of the body 16 which compensates for longitudinal contractile action of the member 38. Any suitable means may be used for maintaining the respective end portions of the member 38 within the grooves 40 and 42. The member 38 and sliding ring 44, in combination with the body I6, thus forms an inflation or expandable chamber 46 which communicates with the reservoir 30 by a plurality of circumferentially spaced slots or wall ports 48 formed through the body shoulder 32.
The reservoir 30 and chamber 46 are filled with a selected fluid S0. The dimensions of the reservoir 30, in combination with the chamber 46, are such that the volume of fluid 50 contained therein will be sufficient to dilate the member 38 as hereinafter explained. The reservoir 30 and chamber 46 are maintained fluidtight to prevent loss of fluid 50 by O-rings 52 disposed in suitable grooves formed on the periphery of the upper end portion of the mandrel 20, on its pistonlike flange 34 and the inner surface of the ring 44.
The depending end portion of the mandrel 20 is provided with an enlarged portion forming an annular shoulder 54. A helical spring 56 surrounds the depending end portion of the mandrel between its shoulder 54 and the body connected lock ring 36. The purpose of the spring 56 is to normally maintain the mandrel and body in extended telescoped relation so that the packer member 38 will be normally maintained in collapsed position, as shown in FIGS. 1 and 3. The depending end of the mandrel 20 is provided with threads 58 forming a tool joint for connection with tubular members 12A forming a part of or a continuation of the well string 12. Obviously the sliding surfaces of the mandrel 20 and body 16 may be keyed or splined for rotating the mandrel.
OPERATION In operation the device is run into a borehole or the casing 114 and supported by the well string 12. The mass of the depending portion of the string 12A, in cooperation with the expansive action of the spring 56 and compressive force of fluid in the borehole annulus, normally maintains the packing member 38 in collapsed position. When it is desired to expand the member 38, into sealing relation with the casing 114 or a borehole wall, the depending end portion of the well string ll2A is set down on the bottom or a suitable bridge formed in the borehole, neither of which are shown, so that further lowering of the well string 12 telescopes the body 16 downwardly over the upper end portion of the mandrel 20 thus moving the shoulder 32 toward the pistonlike flange 34.
The spring 56 is being compressed during this action and the fluid 50, within the reservoir 30, is forced through the ports 48 and into the chamber 46 which forcibly distorts and dilates the member 38 into contact with the inner wall surface of the casing 14 thus forming a fluidtight seal therewith. This setting down or pushing" action of the body 16 over the mandrel 20 utilizes the mass of the well string 12 to increase hydraulic pressure into the chamber 46 and an efficient expanding action of the member 38. However, it seems obvious that the position of the reservoir 30 and chamber 46 may be inverted so that a lift or pull" on the wall string 12 would similarly force the fluid 50 out of the reservoir 30 and into the chamber 46 to expand the member 38. To achieve this it would be necessary to use expandable slips connected with the well string portion 12A, which are normally set and released by a rotative action of the well string, to maintain the mandrel 20 rigid while the lift or pull" action is performed. When it is desired to release the packer, the member 38 is collapsed by simply lifting the well string 12 wherein the body 16 longitudinally slides along the mandrel 20 until the lock-ring 36 again contacts the pistonlike flange 34. This repositions the wall surfaces forming the reservoir 30 to the position shown by FIG. 3, wherein reduced pressure within the reservoir 30 draws or pulls" the fluid out of the chamber 46 to allow the resilient member 38 to return to its collapsed position. This packer setting and releasing action may be repeated as often as desired.
Repeated distortion of the member 38 may tend to prevent its returning to the desired position shown in FIG. 3, however, to more nearly achieve this action a helical spring, not shown, may be interposed in the chamber 46 to bear against the adjacent surface of the shoulder 32 and sliding ring 44.
Obviously the invention is susceptible to changes or alterations without defeating its practicability, therefore, I do not wish to be confined to the preferred embodiment shown in the drawings and described herein.
1. An inflatable packer, comprising:
an elongated tubular body adapted to be connected with a well string and lowered in a borehole;
a tubular mandrel telescopically received by the inner wall surface of said body, one end portion of said body being circumferentially enlarged to define an outwardly projecting annular shoulder and a cylindrical wall surrounding an intermediate portion of said mandrel in spaced-apart relation forming a fluid containing reservoir between said body and said mandrel;
a pistonlike wall formed on the periphery of said mandrel and slidably received longitudinally by the inner surface of said cylindrical wall for movement toward and away from said annular shoulder during telescopic movement of said mandrel;
a lock ring surrounding said mandrel on that side of its pistonlike wall opposite said annular shoulder and coaxially connected with the end portion of said cylindrical wall opposite said annular shoulder;
a cylindrical ring slidably surrounding the end portion of said body opposite said lock ring; and
a flexible and expandable cylindrical member longitudinally surrounding said body in circumferential spaced relation and connected, at its respective end portions, with said annular shoulder and said cylindrical ring for forming an inflation chamber, said annular shoulder having ports providing communication between the reservoir and the inflation chamber, whereby fluid is forced from the reservoir into the inflation chamber in response to telescopic movement of said mandrel into said body for expanding said flexible member into sealing relation with the wall forming the borehole.
2. Structure as specified in claim 1 in which the end portion of said mandrel opposite said body is circumferentially enlarged to form a mandrel shoulder facing toward said body, and a spring interposed between said mandrel shoulder and said lock ring for urging said body and said mandrel toward an extended telescopic relation.