Inflatable packer

Abstract

A field dressable inflatable packer for use in wells which includes a resilient sleeve disconnectably connected on a tubular member by clamping means.

Description

BACKGROUND OF THE INVENTION

This invention relates to an inflatable packer for use in wells and, more particularly, this invention relates to an inflatable packer which utilizes disconnectable clamping means for connecting a resilient inflatable sleeve element of the packer to the body of the packer to make for ease of assembly and disassembly of the packer under field conditions.

As is well known in the art inflatable packers have many uses in well operations. There have been, of course, many different embodiments of inflatable packers known and used heretofore. An inflatable packer generally includes an inner mandrel and a resilient element carried by the mandrel for sealing engagement with a well wall, casing or liner. Heretofore, inflatable packers have been rather complex, expensive pieces of apparatus which were not readily adaptable to low cost repetitive field operations. The present invention is directed to providing a low cost field dressable inflatable packer for use in wells.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is directed to a field dressable inflatable packer. An elongated resilient sleeve is positioned over a tubing section. Clamping means are provided to disconnectably connect the ends of the sleeve in air-tight relationship to the tubing section. Means are provided to inflate the sleeve to cause it to expand.

The clamping means of the present invention disconnectably connect at least one end of the resilient sleeve to the tubing section in fluid-tight relationship therewith. A mandrel section having a central opening to slideably receive the tubing section is provided with serrations on the outside of one end for engagement inside the resilient sleeve. A compressible sleeve having inner serrations fits over the mandrel section and is adapted to engage the outside of the end of the resilient sleeve. A tapered collar slideably engages over the compressible sleeve. As the collar is forced down on the sleeve the sleeve is compressed and forced against the resilient sleeve. The resilient sleeve is thus engaged between the mandrel section and the compressible sleeve. Locking means are provided to maintain the compressible sleeve in such position to disconnectably connect the end of the resilient sleeve to the tubular section.

OBJECTS OF THE INVENTION

The principal object of the present invention is to provide a field dressable inflatable packer which includes a resilient sleeve disconnectably connected to a tubular mandrel section and means for inflating such sleeve. Further objects and advantages of the present invention will become apparent from the following detailed description read in light of the drawing which is a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation view with portions broken away for clarity of presentation and illustrates the lower portion of apparatus assembled in accordance with the present invention;

FIG. 2 is an elevation view and a continuation of FIG. 1 and illustrates the upper portion of apparatus assembled in accordance with the present invention;

FIG. 3 is a sectional view taken at line 3--3 of FIG. 2; and

FIG. 4 is a sectional view taken at line 4--4 of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred arrangement of apparatus of the present invention will now be described in detail with reference to the drawings and to FIGS. 1 and 2 in particular. The apparatus of the present invention provides an inflatable packer useful in well operations. The inflatable packer includes a tubular mandrel section having a resilient inflatable sleeve disconnectably connected thereto and inflatable to sealingly engage the inside of a well. The inflatable packer is illustrated inside of well casing 22. The casing 22 is used to line the wall of the well as is known in the art.

An inflatable resilient sleeve 10 is disconnectably connected at its upper and lower ends in fluid-tight relationship to an elongated tubular mandrel section 12. The connection is made by releaseable clamping units indicated generally by the numerals 14 and 16. The tubing section 12 extends through the clamping units 14 and 16. The upper end of the tubing 12 is usually connected into a segmented tubing string which extends to the top of the well. If desired, however, the tubing section may be connected through an appropriate linkage system to a wireline. In this event suitable inflation devices for inflating the inflatable element are run into the well with the tubing section on the wireline. When the tubing section is run into the well on a segmented tubing string the resilient sleeve 10 is inflated by flowing a fluid such as gas or liquid down the interior of the tubing string into the tubing section and then through the tubing section through a suitable hole 20 therein provided.

The lower end of the tubing section 12 is connected to a float shoe 24 by means of an intermediate sub 26. The float shoe 24 has a plurality of holes 28 to permit entry of well fluids into the interior of the shoe 24. An upwardly opening check valve, such as flapper valve 30, is located in the float shoe 24 above the holes 28. When the flapper valve is open well fluids can communicate with the interior of the tubing section 12 and the tubing connected thereabove.

When well liquids are encountered when the inflatable packer of the present invention is being run into a well on a segmented tubing string the flapper valve 30 opens to permit entry of the well fluids into the interior of the tubing section 12 and the tubing string. This equalizes the pressure on the interior and the exterior of the packer and permits later inflation of the inflatable resilient sleeve 10 by means of a relatively small pressure differential. This is so because the pressure needed to inflate the resilient sleeve does not need to overcome the well pressure.

When fluid is injected into the tubing section from above to apply pressure to the inflatable resilient sleeve the flapper valve is closed by the pressure and the sleeve is expanded by means of flow into the annular chamber 11 between the tubing section 12 and the resilient sleeve 10. Even though a column of well liquids may extend up the interior of the tubing and into the annular chamber 11 the packer is still inflated by pressurizing the tubing string from the surface. After the inflatable packer operation is completed and it is desired to deflate the packer and remove it from the well a drain port is opened below the tubing section 12 to allow the interior of the tubing to drain. Thus knock-off plug 32 is positioned in the adapter sub 26. A sinker bar (not shown) is used to shear off the back of the plug 32 to open communication from the inside of the tubing to the well annulus.

The inflatable resilient sleeve 10 of the packer is preferably formed of rubber or a rubber-like material. The sleeve must be capable of being expanded and retracted numerous times. In preferred form the resilient sleeve is formed by extruding a sleeve of rubber stock material of suitable diameter for the particular packer desired. Suitable reinforcing may also be desirable in the rubber sleeve. Physical properties of the rubber used in one suitable resilient sleeve were found to be as follows: elongation 450 percent minimum; tensile strength 2,500 lbs./in..sup.2 ; shore hardness 70; and tear 250 lbs./inch.

The inflatable sleeve 10 of the packer is connected at its upper and lower ends in fluid-tight relationship by clamping units 14 and 16. The clamping units 14 and 16 disconnectably connect the flexible sleeve 10 in position over the tubing section 12. The disconnectable connection provided by the clamping units permits easy field repair or "dressing" of the packer. Thus if the ends of the sleeve wear or abrade near the clamping units then one or more of the clamps is opened and the worn end or ends of the sleeve trimmed off. The sleeve is then reconnected into the clamping unit.

The clamping unit of the present invention includes a serrated mandrel section 34 which fits closely in sliding relationship over the tubing section 12. Since the clamping unit is slideable on the tubular section it may be repositioned on the tubular section to accommodate a resilient sleeve which has been shortened by field dressing. A pair of interior O-rings 36 and 38 provide a fluid-tight seal between the tubing section 12 and the mandrel section 34. Clamping rings 40 and 42 are connected to the exterior of the tubing section 12 above and below the mandrel section 34 to limit its movement on the tubing section. It is noted that the clamp rings 40 and 42 can easily be snapped off and repositioned on the tubing section 12. Thus if the flexible sleeve 10 is shortened during field dressing the clamp rings 40 and 42 are disconnected and the serrated mandrel and the rest of the clamping unit are slid to a new position on the tubing section 12 and the clamp rings connected. The shortened resilient sleeve is then reconnected at such position.

The outside of the mandrel section 34 which engages the resilient sleeve 10 has a series of radially extending serrations located on one end beneath a flange 44 formed on the mandrel section 34. The other end of the outside of the mandrel section 34 is provided with threads. A compressible sleeve 46 is provided with interior serrations. The serrated sleeve 46 cooperates with the serrated portion of the mandrel section 34 to grip an end of the resilient sleeve 10. A flange 48 on the serrated sleeve 46 mates with the radial flange 44 of the mandrel section to limit travel of the sleeve over the mandrel section. The serrated sleeve is partially cut longitudinally on the end away from flange 48. These longitudinal cuts extend over a substantial portion of the sleeve 46 to provide a series of relatively flexible fingers 50.

A tapered collar 52 slideably engages over the serrated sleeve 46 and as the collar 52 is driven or forced down over the sleeve the serrated flexible fingers 50 are compressed and cooperate with the outer serrations of the mandrel section 34 to snugly engage the resilient sleeve 10. The collar is forced into such position by nut 54. A locking collar 56 locks the nut 54 in position.

Thus in summary the present invention provides a field dressable inflatable packer which includes an elongated resilient sleeve positioned over a tubing section. Clamping means are provided to disconnectably connect the ends of the sleeve in fluid-tight relationship to the tubing section and means are provided to inflate the sleeve to cause it to expand. The clamping means disconnectably connect at least one end of the resilient sleeve to the tubing section in fluid-tight relationship therewith and includes a mandrel section having a central opening to slideably receive the tubing section. The mandrel is provided with serrations on the outside of one end for engagement inside the resilient sleeve. A compressible sleeve having inner serrations fits over the mandrel section and is adapted to engage the outside of the end of the resilient sleeve. A tapered collar slideably engages over the compressible sleeve. As the collar is forced down on the sleeve the sleeve is compressed and forced against the resilient sleeve. The resilient sleeve is thus engaged between the mandrel section and the compressible sleeve. Locking means are provided to maintain the compressible sleeve in such position to disconnectably connect the end of the resilient sleeve to the tubular section.

Although certain preferred embodiments of the present invention have been herein described in order to provide an example of its construction and steps sufficient for usage by those skilled in the art, it is to be understood that various changes and innovations in the structure described can be effected without departure from the basic principles of the invention. Changes and revisions of this sort which continue to rely on these principles are therefore deemed to be circumscribed by the spirit and scope of the appended claims.

Claims

I claim:

1. An inflatable packer comprising a tubing section,

an elongated resilient sleeve slideably positioned over said tubing section,

clamping means including a mandril section slidably mounted in fluid-tight relationship on said tubing section disconnectably connecting the ends of said sleeve in fluid-tight relationship with said tubing section to form an annular chamber between said tubing section and said sleeve, clamping rings connectable to the exterior of said tubing section above and below said mandril section of said clamping means to limit the movement of said clamping means on said tubing section and

port means providing a passageway for flowing fluid into said annular chamber to inflate said resilient sleeve.

2. An inflatable packer comprising a tubing section,

an elongated resilient sleeve removably positioned over said tubing section and forming an annular chamber therewith,

clamping means disconnectably connecting the ends of said sleeve in fluid-tight relationship with said tubular section,

at least one of said clamping means comprising

a mandrel section slideably mounted in fluid-tight relationship on said tubular section,

a compressible sleeve removably positioned over said mandrel section and cooperating with said mandrel section for receiving one end of said resilient sleeve therebetween,

a tapered collar arranged coaxially over said compressible sleeve and adapted to be moved to compress said compressible sleeve,

and means for moving said tapered collar to compress said compressible sleeve to engage the end of said resilient sleeve between said compressible sleeve and said mandrel,

and port means providing a passageway for fluid flow into said annular chamber to inflate said resilient sleeve.

3. The packer of claim 2 further characterized in that said clamping means are movable longitudinally with respect to said tubing section when said sleeve is disconnected from said clamping means.

4. The packer of claim 3 further characterized in that clamping rings are connected to the exterior of said tubing section above and below said clamping means to limit the movement of said clamping means on said tubing section.