Fluid retainer setting tool

Abstract

The invention is a cement retainer setting tool for use with cement slurry or similar liquid retainer devices in a well bore. The setting tool has a centrally disposed elongated mandrel which has one end adapted to be coupled to a string of tubing and a tubular stinger element extending downwardly from the lower end of the mandrel. The lower end of the mandrel has means thereof for coupling a cement retainer thereto. An outer sleeve surrounds the mandrel along most of its length and has left hand threads along its inner surface. An inner sleeve having left handed threads on its outer surface which are coupled to the threads on the outer sleeve is coupled to the mandrel so that rotation of the mandrel rotates the inner sleeve. The inner sleeve also has a circumferential array of bores which contain ball detent elements which extend into a recess of the outer surface of the mandrel except when relative movement between the inner sleeve and the outer sleeve allows the balls to move into a recess in the inner wall of the outer sleeve, thereby permitting slidable downward movement of the mandrel with respect to the outer sleeve.

Description

BACKGROUND OF THE INVENTION

This invention relates to fluid (usually cement slurry) retainer setting tools for use in earth wells or the like.

In many earth wells it is desirable to set in position in a bore hole (usually cased with steel well casing) a fluid retainer unit which in effect seals off that part of the bore hole lying below the retainer unit. Such retainers comprise, for example, a combination packer assembly and an internal valve which is operable to permit the passage of fluid through the unit into the well bore below the retainer unit.

The fluid retainer unit is commonly attached to the lower part of a retainer setting tool which, in turn, is attached at its upper end to a string of tubing.

Prior art retainer setting tools exist for the various types of fluid retainer units, but are often complex to assemble, expensive to machine the components thereof, or, under some well conditions wherein the mandrel part of the fluid retainer has moved downward, the retainer setting tool is unable to actuate the valve in the retainer unit.

OBJECTS OF THE INVENTION

A principal object of this invention is to provide an improved fluid retainer setting tool for use in a bore hole or the like.

Another object of this invention is to provide an improved, more reliable fluid retainer setting tool for use in bore holes or the like.

A further object of this invention is to provide an improved, more positive acting fluid retainer setting tool for use in bore holes or the like

STATEMENT OF INVENTION

In accordance with this invention, there is provided a retainer setting tool for use with cement slurry or similar fluid retainer devices in a well bore. The setting tool has a centrally disposed elongated mandrel which has one end adapted to be coupled to a string of tubing and a tubular stinger element extending downwardly from the lower end of the mandrel. The lower end of the mandrel has means thereon for coupling a cement retainer thereto.

An outer sleeve surrounds the mandrel along most of its length and has left hand threads along its inner surface. An inner sleeve having left handed threads on its outer surface which are coupled to the threads on the outer sleeve is coupled to the mandrel so that rotation of the mandrel rotates the inner sleeve.

The inner sleeve also has a circumferential array of bores which contain ball detent elements which extend into a recess of the outer surface of the mandrel except when relative movement between the inner sleeve and the outer sleeve allows the balls to move into a recess in the inner wall of the outer sleeve, thereby permitting slidable downward movement of the mandrel with respect to the outer sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, as well as additional objects and advantages thereof, will best be understood when the following detailed description is read in connection with the accompanying drawings, wherein:

FIG. 1 is a side elevational view, partly in section, of a fluid retainer setting tool having a fluid retainer unit attached thereto;

FIG. 2 is a sectional view taken along the line 2--2 of FIG. 1;

FIG. 3 is a sectional view taken along the line 3--3 of FIG. 1;

FIG. 4 is a sectional view taken along the line 4--4 of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to the drawings, there is shown a fluid retainer setting tool, indicated generally by the numeral 10, having a fluid retainer, indicated generally by the numeral 12, coupled to the lower end part of a generally tubular inner mandrel 22, bottom connection coupler 14, stinger connection element 16 and swivel connection element 18.

The swivel connection element 18 is generally tubular in configuration with one end having an inwardly extending shoulder 20 and the other end having internal threads which engage external threads at the lower end 36 of the mandrel 22.

The stinger connection element 16 is a generally tubular element having threads 24 on the external surface of the end 26 that is remote from the mandrel 22. The connection element 16 has an outwardly extending boss on its outer surface about one-third of its length above the end 26. The boss 28 has generally perpendicular shoulders 30, 32, and fits closely but slidably against the inner surface of the swivel connection element 18.

A bearing 34 is provided between the shoulder 30 and the inwardly extending shoulder 20 of the swivel connection element 18. The shoulder 32 seats against the lower end 36 of the mandrel 22.

The outer surface of the stinger connection element 16 above the shoulder 32 fits closely but slidably along the inner surface of the lower end part of the mandrel 22. A seal 38 is provided between the outer surface of the connection element 16 and the inner surface of the mandrel 22.

The bottom connection coupler 14 is a generally tubular element having an outwardly extending shoulder 40 at its end which is coupled to the stinger connection element 16. The coupler 14 also has an inwardly extending circumferential boss 42 with generally perpendicular walls about midway between the ends of the coupler 14 around the inner wall of the coupler 14. There are threads 44, 46 in the upper and lower internal surface parts of the coupler 14 and external threads 48 below the outwardly extending shoulder 40. A tubular, elongated stinger element 50 is coupled at its upper threaded end 52 to the threads 44 of the bottom connection coupler 14. Seals 54, 56 are provided between the stinger 50 and coupler 14 and between the stinger connection element 16 and the coupler 14, respectively.

The fluid retainer device 12 is coupled to the external threads 48 of the coupler 14 by means of the upper internal threads 60 of a coupler 58.

The stinger 50 extends downwardly through the interior of the retainer device 12, its outer surface sealing against the seal 62 in the inner surface of the upper mandrel part 64 of the device 12.

The coupler 58 has internal threads 66 which engage the external threaded end part of the mandrel 64 of the device 12. The coupler 58 has a thin walled intermediate part 70 which is adapted to shear under conditions to be mentioned later.

As may be seen, the lower end 72 of the stinger 50, within the device 12, lies against the valve actuating sleeve 74 thereby holding the valve in full open position when the setting tool 10 and retainer device are assembled to be run down a bore hole.

A lock ring 76 and setting ring 78 prevent unwanted upward movement of the mandrel 64 to prevent accidental setting of the packer part 80 of the device 12.

Returning now to the retainer setting tool 10, the elongated generally tubular mandrel 22 is of generally constant inner diameter from the upper end 82 where it is sealed and coupled to the top connection element 84 whose internal threads 86 are adapted to be coupled to the lower end of a string of tubing or the like 87, for example to a point just above the upper end of the stinger connection element 16. From that point to its lower end, the inner diameter of the mandrel 22 is somewhat larger.

The outer diameter of the mandrel 22 is constant from the top connection element 84 to the point 88 and of the same constant diameter between the point 90 and the point where the mandrel 22 is coupled to the swivel connection 18.

The outer diameter of the mandrel 22 is less between points 88 and 90 to permit easier upward movement of the mandrel 22 as will be explained later.

An elongated outer sleeve 92, of large enough inner diameter so that the sleeve 92 fits over and is spaced from the mandrel 22, swivel connector 18 and bottom connection coupler 14, extends from below the lower end of the coupler 14 to between the points 88, 90 along the mandrel 22. The upper end part of the outer sleeve has a coupling part 94 including outer threads 96 at its upper end and a shoulder 98 at the lower end thereof.

An elongated so-called threaded sleeve 100 is coupled at its internally threaded end 102 to the threads 96 and extends upwardly a substantial distance. The upper part of the threaded sleeve 100 contains left hand threads 104 on its inner surface for a substantial distance. Just below the threaded part (threads 104) is an inwardly extending grooved part 106 in the inner wall of the threaded sleeve 100.

Between the threaded sleeve 100 and the outer surface of the mandrel 22 there is disposed an elongated sleeve-like setting nut 108. The setting nut 108 has left hand threads 110 on its upper part which engage the threads 104 of the threaded sleeve 100. A circumferential array of bores 112 extend around and through the lower end part 114 of the setting nut 108. The bores are disposed just below the point 88 where the outer diameter of the mandrel 22 is reduced (between points 88, 90). Each of the bores 112 contains a ball-like detent element 116 which extends into the reduced diameter space between the points 88, 90 on the mandrel 22.

The setting nut 108 and the part of the mandrel 22 disposed adjacent thereto each have a key slot (in their inner and outer diameters, respectively) into which a key 118 fits, locking the mandrel 22 to the setting nut 108 (see FIG. 3 also).

A releasing nut 120 having a sleeve-like part corresponding to the upper threaded part of the setting nut 108 (including left hand threads on its external surface) and an outwardly extending shoulder part 122, is threaded along the upper end part of the threaded sleeve 100.

A rubber bumper 128 is provided between the shoulder 122 and the upper end of the threaded sleeve 100.

The releasing nut 120 and mandrel 22, like the setting nut 108 and mandrel 22, have longitudinally extending slots (93 in the mandrel 22) in their respective internal and external surfaces to receive a key 130 (see FIG. 2).

This key 130 locks the releasing nut 120 to the mandrel 22 so that rotation of the mandrel 22 also rotates the releasing nut 120. The inner surface of the shoulder end of the releasing nut 120 has threads 124 above the part where the key 130 ends.

The threads 124 receive the threaded end part 132 of a lock nut 134 which fits around the mandrel 22 and abuts against the shoulder 126 of the releasing nut 122 and also against a shoulder on the mandrel 22 at the upper end of the key 130.

An elongated space sleeve 136 fits closely but slidably around the mandrel 22, its upper end bearing against the shoulder 98 of the upper end part of the outer sleeve 92. Upward movement of the mandrel 22, should the left handed threads in the threaded sleeve 100 be completely disengaged from the left handed threads in the setting nut 108 and releasing nut 120, causes the outwardly extending upper end part 138 to bear against the lower end 140 of the spacer sleeve 136, permitting the entire retainer setting tool 10 to be withdrawn with upward movement of the mandrel 22.

An array 142 of drag springs is secured to the outer sleeve 92 near the lower end part of the sleeve 92.

A centralizer element 144 is secured to the outer surface of the outer sleeve 92 near or at its upper end.

A bolt 146 extends through the outer sleeve 92 and into the bottom connection coupler 14 at the end part 40. This bolt 146 permits the retainer device 12 to be coupled to the coupler 14 by preventing rotation of the coupler 14. After the retainer device 12 is coupled to the coupler 14, the bolt 146 is removed.

OPERATION

In operation the retainer setting tool 10 is coupled to the fluid retainer device 12 with the threads 60 of the coupler 58 engaged with the threads 48 of the bottom connection coupler 14.

The stinger 50 extends into the mandrel 64 of the device, past the seal 62 and having its lower end 72 contacting the upper end of the valve actuating sleeve 74 to hold the retainer valve (not shown) in the open position.

The first operation of the retainer setting tool 10, after it and the device 12 have been lowered on the end of a string of tubing to the designated position in the well bore, is to set the packer element 80 of the device 12 to provide a seal between the device 12 and the wall of the casing (not shown) in the well.

It will be noted that the lower end 150 of the outer sleeve 92 contacts, or almost contacts, the upper end of the setting ring 78. The lower or tapered end of the setting ring 78 fits under the inner surface of the lock ring 76.

The packer is set by rotating the tubing (not shown, but coupled to threads 86 of the top connection element 84) to the right. This right hand rotation rotates the mandrel 22, setting nut 108, and releasing nut 120 which are coupled to the mandrel by keys 118 and 130, respectively. The right hand movement of the nuts 118 and 130 rotates the left hand threads of these parts in the left hand threads 104 in the threaded sleeve 100. The threaded sleeve 100 is prevented from making rotational movement by the drag springs 142.

Thus, right hand rotation of the tubing (not shown) forces the threaded sleeve 100 and outer sleeve 92, to which it is coupled (threads 96) downwardly, forcing the lower end 150 of the sleeve 92 to drive the setting ring downwardly to expand the lock beyond the shoulder 152 on the mandrel 64. The mandrel 64 is then drawn up by upward movement of the tubing (not shown) to which it is coupled through the mandrel 22 of the setting tool 10, thus setting the packer element 80. When the tubing is drawn upwardly, the outer sleeve 92 remains where it is (no drag spring movement) because the releasing nut 120 has been released from the threads 110 by the above mentioned right hand rotation of the tubing. The mandrel 22 thus is free to move between the shoulders 88, 90. Before the right hand rotation of the tubing, the lower end of the releasing nut 120 bears against the slotted shoulder of the mandrel 22. The releasing nut 122, until disengaged, holds the mandrel 22 and threaded sleeve 100 in fixed relationship with respect to each other. During the setting of the packer element 80, the slips 154, 156 expand, the pins 158, 160 are sheared and the packer element is compressed between the slips. Setting the slips usually requires that a substantial part of the left hand threads be unscrewed with respect to each other.

Once the packer element 80 is set, further upward movement of the mandrel 22 with respect to the outer sleeve 92 (using more right hand turns of the tubing) results in the shearing of the coupler 58 at its thinned part 70. The shearing force is slightly in excess of the force required to set the packer.

Once the coupler 58 is sheared, the mandrel 22 is advanced upwardly so the lower end 72 of the stinger 50 is below the seal 62 yet is free of the valve actuating sleeve so the retainer valve (not shown) closes. The tubing may then be pressurized to check the system for leaks. Assuming no leaks, the tubing is lowered, lowering the mandrel 22 and its attached stinger 50 so that the end 72 of the stinger lowers and forces downwardly the valve actuating sleeve 74, opening the valve (not shown) in the fluid retainer device 12.

A cement slurry or other pumpable fluid material may then pass through the tubing, mandrel 22, stinger 50, the open valved retainer device 12 and into the bore hole below the device 12.

However, sometimes the stinger 50, when lowered, cannot be lowered far enough to open the valve in the device 12. As the packer is being set the pins 158, 160 shear. Thus the only thing preventing about two inches (more or less) of movement of the rubber-like packer element 80 with respect to the mandrel 64 is friction. The effect of this movement, if it occurs, is to lower the mandrel 64 to a point where lowering of the stinger 50 on the setting tool 10 no longer depresses the valve actuating sleeve 74 enough to open the valve in the retainer device 12.

If such mandrel slippage occurs, further right hand rotation of the tubing (and mandrel 22) results in further downward movement of the threaded sleeve 100 with respect to the mandrel 22 until the recess 106 is aligned with the array of balls 116 which lie in holes 112 around the circumference of the lower end 114 of the setting nut 108. Until the recess 106 is aligned with the balls 116, the balls extend through the wall of the setting nut and prevent free downward movement of the mandrel 22 because they bear against the shoulder 88.

However, when the recess 106 is aligned with the balls 116, the balls move into the recess enough to permit the mandrel 22 to move lower, the shoulder 88 being free to pass the balls 116.

This additionally available downward movement of the mandrel 22 permits the stinger 50 to depress the valve actuator sleeve 74 sufficiently to open the valve in the retainer device 12 even though the mandrel 64 of the device 12 has slipped downwardly.

After the fluid of the well treating operation is completed, the stinger 50 is withdrawn from the device 12 (as the tubing to which the tool 10 is attached is withdrawn), and the valve in the retainer device 12 closes.

In event the left hand threads of both the threaded sleeve 100, setting nut 108 and releasing nut 120 are completely disengaged with respect to each other, an elongated sleeve 136 which fits loosely around the mandrel 22 results in the whole tool 10 being withdrawn when the tubing is pulled up. The lower end 140 of the sleeve 136 bears against the upper end 138 of the swivel connection element 18, while the upper end of the sleeve 136 bears against the shoulder 98 of the coupling part 94 of the outer sleeve 92.

Claims

What is claimed is:

1. A cement retainer setting tool for down hole use in a well bore wherein it is coupled to the lower end of a string of tubing, comprising an elongated hollow mandrel having an upper end and a lower end, an elongated tubular stinger element, said upper end of said mandrel being coupled to said tubing string and said lower end being coupled to one end of said stinger element, said tubing, mandrel and stinger element being in axial alignment, means adjacent to said lower end of said mandrel for coupling a cement retainer device in swiveling relationship with respect to said mandrel, an outer housing having an outer and inner wall and an upper and lower end, said outer housing surrounding said mandrel in spaced relationship with respect thereto from its lower end part to near its upper end part, said outer housing having an array of left hand threads along its inner wall, said left hand threads being disposed at its upper end part, said outer housing having a recessed inner wall part adjacent to the part of said array of left hand threads which is remote from said upper end of said outer housing, a tubular sleeve having an inner and outer wall and upper end and lower end parts, said sleeve fitting between said mandrel and said outer housing and having an array of left hand threads on said outer surface of said upper end part, said last mentioned threads being coupled to said array of said left hand threads of said outer housing, said tubular sleeve having an array of bores extending therethrough, said bores lying generally along a plane perpendicular with the longitudinal axis of said mandrel, said mandrel having a recessed part adjacent to said bores, said bores each containing a detent element, the thickness of said detent elements being such that they extend from said outer housing into recessed part of said mandrel, said recessed inner wall part of said outer housing being disposed no further from said detent elements than the length of said array of left hand threads, and means mechanically coupling said tubular sleeve to said mandrel whereby right hand rotation of said mandrel rotates said sleeve and said left hand threads thereon to force said outer housing downwardly with respect to said mandrel until said detent elements retract into said recessed inner wall part to permit limited lowering of said mandrel through said outer housing.

2. A tool in accordance with claim 1 wherein said stinger element is adapted to extend into and at least contact a valve actuator in said cement retainer device.

3. A tool in accordance with claim 1 wherein said outer housing has an array of drag springs coupled to its outer wall.

4. A tool in accordance with claim 1 wherein said tubular sleeve is coupled to said mandrel by key means.

5. A tool in accordance with claim 1 wherein said detent elements are ball elements.

6. A tool in accordance with claim 1 wherein the lower end of said outer housing is of larger inner diameter than the means for coupling said retainer device to said mandrel.