US2795856A - Control mechanism for elements in well tools - Google Patents

Description

June 18, 1957 c. E. REESBY ETAL 2,795,356

. CONTROL MECHANISM FOR ELEMENTS m WELL TOOLS Filed Nov. 25, 1955 Caf/ Reesby -0r|// //e f3. 6777/? INVENTORS BY 7 .m advwa United States Patent CONTROL NIECHANISM FOR ELEMENTS IN WELL TOOLS Carl E. Reesby and Orville R. Smith, Houston, Tex., assignors to Halliburton Oil Well Cementing Company, Harris County, Tex., a corporation of Delaware Application November 25, 1955, Serial No. 549,058

7 Claims. (Cl. 33-178) This invention relates to tools used in wells and other earth bore holes and remote locations, and more particularly, to a mechanism for the control of certain elements in such tools.

In many tools used in remote locations such as the bottoms of oil wells, it is necessary to obtain substantial forces for the control of certain elements in the mechanism of such tools. The problem is illustrated in the caliper of Figure 1, wherein it is desired to hold the feelers retracted during descent into the well, then to release them for calipering during some distance of upward movement of the caliper, and wherein it is sometimes desired to again retract the feelers and lower the tool again for a second calipering pass through a given section of the well, before pulling the tool up to the top of the well. When the tool is suspended perhaps two miles down in a well on a wire line, repeated control of the feelers, to the extent of locking them in a retracted position and releasing them for calipering, presents some difficulties.

While some electrical energy may be transmitted to the tool in some uses, it is usually very difficult to transmit enough electric energy to directly control such members as feelers, spring loaded arms, pads or packers, in calipers, well logging and similar instruments, through a full cycle or more of operation and by conventional electric direct control means.

An object of this invention is to provide improved control means for movable members in tools used in remote locations such as oil wells.

A further object of this invention is to provide novel control means, wherein the energy of the fluids at the remote location is utilized for desired control purposes.

Still another object is to provide an improved and novel caliper wherein the feelers thereof may be released for calipering and thence retracted again through a plurality of half-cycles, while the caliper remains positioned in a well.

Other objects are apparent from the following description and accompanying drawing.

These objects are accomplished in accordance with this invention, by the use of a hydraulic system, including a high pressure chamber containing hydraulic fluid in communication with a low pressure chamber, at least partially filled with compressible gas. The high pressure chamber is in pressure communication with the fluid pressures external of the subject tool or instrument, whereas the low pressure chamber is initially at relatively low pressure such as atmospheric pressure. Fluid flowing from the high pressure to the low pressure chamber moves with the energy derived from the difierence between the pressure external of the tool in the well and that in the low pressure chamber. A motor responsive to the movement of hydraulic liquid from one chamber to the other, is adapted to control the retractable or other movable member of interest in the instrument.

Figure 1 is an illustration of a typical caliper embodying the invention.

Figure 2 is a schematic view of the hydraulic system used in the caliper of Figure 1, and usable in other tools ice to control retractable members through more than onehalf cycle.

Figure 3 is a schematic view of another embodiment of the hydraulic system of the invention.

In order that the problem solved by this invention may be fully understood, reference may be made to the caliper of Figure l.

The caliper body 1 is depended from a logging line 2. The logging line 2 includes both such electrical conductors as are required for the operation of the caliper electrical elements and for recordation of the data from the caliper, as indicated hereinafter.

Near the lower end of the caliper, a plurality of bell crank levers 4 are pivotally mounted on the caliper body 1 by pins 5. Each bell crank lever lies in a plane radial from the caliper body, with the shorter end extending generally inward, and the longer end extending generally downward and protruding outward from the caliper for engagement with the wall of the well. Accordingly, the outer end of each bell crank lever becomes a feeler.

Each feeler is urged outward by the action of a tension coil spring 7 mounted in the caliper to act upon a stem 8 which in turn urges the short end of the bell crank lever downward.

At one end each stem 8 carries a rack 10, which cooperates with a pinion 11. The pinion 11 controls a potentiometer which is immediately behind the pinion 11, and therefore does not appear in Figure 1. The position of the feeler controls the setting of the potentiometer, and a signal derived from the potentiometer is indicative of the position of the feeler. The potentiometers are energized from the logging line 2 and the signals derived from the various potentiometers are, either together or separately as may be desired for the particular caliper operation, transmitted to the top of the well through the logging line 2.

If the caliper is to be lowered into the well, the caliper fingers must be held retracted. When the tool is positioned as low in the well as desired, the fingers must be released, and then the calipering run commenced. If a calipering run is made for, say 200 feet, and it is desired for some reason to re-run the same 200 feet, the feelers must be retracted again for the 200 foot descent, then released again for the 200 foot calipering run. If no further calipering is desired, it is preferable to again retract the feelers for the run back to the surface of the ground, which may be as much as two miles or more in deep wells.

In the caliper illustrated, the feelers as a group are held retracted during descent into the hole, by a collar 13, adapted to engage all of the inside ends of the bell crank arms 4 on the lower side. The collar 13 is mounted on a rod 14. When the rod 14 is held upward, the collar 13 controls the feelers, locking them inward, but when the rod 14 and collar 13 are moved downward, the feelers extend outward freely for their calipering function.

The mechanism for controlling the reciprocating rod 14, and thereby controlling the retractable feelers, is more easily understood by first referring to the hydraulic system detailed schematically in Figure 2.

In the hydraulic system of Figure 2, there are three cylinders, 15, 16 and 17. Preferably, the first cylinder 15 is of substantially smaller volume than the second and third cylinders 16 and 17.

The rod 14 appears both in Figure l and Figure 2, and protrudes axially into the cylinder 15. On the end of the rod 14 within the cylinder 15, there is a first piston 20 which divides the cylinder 15 into two chambers, a first chamber 21 and a second chamber 22.

Within the cylinder 16, there is a second piston 25 which divides the cylinder 16 into an anterior chamber 26. and a posterior chamber 27. Conveniently there may' be a valve 28 which when open, connects the posterior chamber to atmosphere. The valve 28 is closed during the operation of the device, but may be used to relieve any pressure which may accumulate in the chamber 27 before disassembly of the tool for repairs, or to remove any hydraulic fluid that may seep by the piston 25. Within the posterior chamber 27, there may be a compression spring 29 adapted to urge the piston 25 toward the anterior chamber 26.

Within the third cylinder 17, there is a third piston 31 which, in co-operation with a portion of the cylinder 17, defines a third or high pressure chamber 32. The side of the piston 31 which is opposite the high pressure chamber 32 is to open to the pressure of fluids imme diately surrounding the tool.

Conduit and valve means are provided for connecting the high pressure chamber 32 into communication with the first chamber 21 and for connecting the second chamber 22 into connection with the anterior chamber 26. Valve and conduit means also afford a connection from the high pressure chamber 32 to the second chamber 22, and from the first chamber 21 to the anterior chamber 26.

Conveniently the valve in such means may be a fourport rotary valve 35, with the four ports positioned at 90 degree intervals around the valve. In the embodiment of Figure 2 (details of which are not shown in Figure 1), one of said ports is connected to the first chamber 21 by a conduit 36; a second port is connected to the high pressure chamber 32 by a conduit 37; a third port, diametrically opposite the first, is connected to the second chamber 22 by a conduit 38; and the fourth port, diametrically opposite the second, is connected to the anterior chamber 26 by a conduit 39.

The four-port valve 35 has 3 positions. In one position, none of the ports are connected to each other, as when it is turned 45 from the position illustrated in Figure 2. With this valve position, hydraulic fluid flow is prevented and therod 14 is thereby locked in the position Where it is when the valve 35 is, turned to this neutral or off position. The other two positions of the valve 35 are the one illustrated in Figure 2, and a position 90 counter-clockwise from that of Figure 2.

A solenoid 40 operating in conjunction with a gear train 41 (see Figure l) operates the valve 35. The solenoid is controlled by surface switches connected by wires in the logging line to the solenoid 40.

The central portion of the housing 1 is a liquid filled chamber housing most of the works of the tool. the top of the housing 1, the housing assumes the form of a cylinder. A piston 42 with an O ring is slidab'ly positioned therein. The upper side of the piston 42 is open, through ports 43, to the well fluids. Accordingly, the liquid below the piston 42 is always maintained at the same pressure as the well fluids external of the tool, and any exposure of the upper side of the piston 31 (Figure 2) to the liquid filling the housing 1, is an exposure of the piston 31 to the pressures of Well fluids.

The operation of this embodiment of the hydraulic system can now be understood. The valve 35 is rotated to connect first the second chamber 22, then the first chamber 21 to the high pressure chamber 32, correspondingly connecting the anterior chamber 26 to the first chamber 21 and to the second chamber 22 at alternate times. Thereby hydraulic fluid, preferably a substantially noncompressible liquid, which fills the various conduits, and the anterior, first, second and high pressure chambers, is moved by the action of the spring 29 out of the anterior chamber 26 and into the high pressure chamber 32. The posterior chamber is occupied with low pressure gas and the valve 28 is closed.

Assume that when the piston 25 is farthest down in Figure 2, that the piston 20 is farthest up in both Figure l and Figure 2. At this time conduit 37 is connected to Near conduit 36 and conduit 38 is connected to conduit 39 by the valve 35. The feelers 4 are then supported in retracted position by the upward position of the collar 137 The tool, in the condition described, is lowered into the well, say 12,000 feet for a number of calipering runs between 12,000 feet and 10,000 feet. At such depths, the amount of electrical power that can conveniently be conveyed to the tool is usually limited, but great power resides in the high pressure of the well fluids, which pressure is greatly above atmospheric pressure.

When the tool reaches 12,000 feet, the solenoid 40 is energized to turn the valve 35 to the position wherein the high pressure chamber 32 is connected via conduits 37 and 38 to the second chamber 22, and so that the first chamber 21 is connected via conduits 36 and 39 to the anterior chamber 26. With the valve in this position, the well pressures acting on the top of the piston 31 create a pressure diflerential across the first piston 20. Hydraulic fluid from the high pressure chamber 32 is urged into the second chamber 22, moving the piston 20, rod 14 and collar 13, downward, releasing the feelers 4. Hydraulic fluid in the first chamber 21 is discharged via conduits 36 and 39 into the anterior chamber 26. The piston 25 is moved upward against the atmospheric pressure and light spring in the posterior chamber 27.

The tool is then pulled upward 200 feet ina calipering run, whereupon it is desired to again retract the feelers. Since the high pressure chamber 32 and the anterior chamber 26 are both larger in volume than is the entirety of the cylinder 15, including both the first and second chambers 21 and 22, the first half cycle of operations require movement of the pistons 31 and 25 of only one-eighth of their travel, for example.

The solenoid 40 is used to rotate the valve 35 so that the high pressure chamber 32 is connected to the first chamber 21, and thesecond chamber 22 is connected to the anterior chamber 26. Thereupon, the well fluids push the piston 31 downward another one-eighth of its travel, thereby returning the piston 20, rod 14 and collar 13 to the upward position, and retracting the feelers 4.

The tool is then lowered again down to the l2,000 foot level, and the cycle repeated. The feelers may be withdrawn and released as many times as desired, until all the hydraulic fluid in the high pressure chamber 32 has been moved out and the anterior chamber 26 has been filled.

It is preferred that before the hydraulic fluid in the high pressure chamber 17 is exhausted, the feelers are retracted. Thereupon, the valve 35 is turned to the neutral or off position, preventing any fluid flow, so as to hold the feelers in the retracted position as the tool is drawn back to the surface of the ground.

When the tool reaches the surface, the valve 35 may be rotated through its extreme positions 90 apart, and the spring 29 then moves the piston 25 downward and causes the hydraulic fluid to return to the high pressure chamber 32. The valve 28 may be opened at this time if desired, though this is not normally necessary.

The hydraulic system has been defined with reference to the Figure 2 embodiment, but other embodiments are equivalent. Consider, for example, the embodiment of Figure 3. Again there is the rod 14 and piston 20. The piston '20 is positioned in a cylinder so as to define therein two chambers which this time are designated and 46. At one side, the left side in Figure 3, of the chambers 45 and 46, is a high pressure chamber 47. The high pressure chamber 47 is defined in part by a flexible diaphragm 48.

On another side of the chambers 45 and 46, the right side in Figure 3, there is a single large chamber divided into an anterior chamber 50 and a posterior chamber 51 by another flexible diaphram 52.

The high pressure chamber 47' is connectable by a valve 54 to the first chamber 45, and by another valve 55 to greases connectable by a valve 56 to the first chamber 45 and by another valve 57 to the second chamber 46. The posterior chamber may be opened to the atmosphere by a valve 58.

If electrical means are provided for the operation of the various valves 55, 56, 57 and 58, then the structure of Figure 3 may be operated identically with that of Figure 2. The rod 14 may be moved downward by opening valves 55 and 56, so that hydraulic fluid, urged by the flexible diaphram 48 which is open to well pressures, is moved from the high pressure chamber 47 into the second chamber 46, and from the first chamber 45 into the anterior chamber 50, causing the flexible diaphram 52 to move against near atmospheric gas pressure in the posterior chamber 51. The rod 14 may be moved upward by Opening valves 54 and 57, so that hydraulic fluid is moved from the high pressure chamber 47 into the first chamber 45 and from the second chamber 46 into the anterior chamber 50.

It is apparent that both the piston 31, of Figure 2, and the flexible diaphram 48 of Figure 3, constitute means for communicating the fluid pressure external of said instrument to the hydraulic liquid in said high pressure chamber. Conventional bellows could also be adapted for this purpose.

The anterior and posterior chambers may be considered as one low pressure chamber, and if desired, the dividing piston (Figure 2) or diaphragm 52 (Figure 3) may be eliminated, without affecting the operation of the device once it is set for lowering into the well with the low pressure chamber substantially full of relatively low pressure gas. The piston 25 and diaphragm 52 are included merely for convenience in resetting the device prior to each run in a well.

Speaking broadly, the cylinder which defines the first and second chambers 21 and 22 (Figure 2) or 45 and 46 (Figure 3) is a motor which is responsive to fluid flow in either of two directions to generate mechanical forces in either of two directions. Other hydraulic motors, i. e., fluid flow responsive means, may be used to convert the fluid flow into mechanicalmotion, although the cylinder piston arrangement has been found to be most convenient for use in well tools.

Other embodiments of the invention will be apparent to those skilled in the art. For example, it may be found convenient to arrange two, or even all three, of the cylinders of Figure 2 concentrically. Accordingly, the foregoing description is to be construed as illustrative only and not as a limitation upon the invention as defined in the following claims.

We claim:

1. In an instrument adapted to be run in a well and having a retractable member adapted to protrude therefrom, a hydraulic system for controlling said member comprising the combination of a first cylinder with a first piston therein which is responsive to hydraulic fluid pressure differentials on opposite sides thereof in either of the two alternative directions, said piston being connected by a linkage to said controlled member whereby said piston drives and controls said member in its movement from one of its positions to the other; a low pressure chamber in the form of a second cylinder, said cylinder being divided into anterior and posterior chambers by a second piston movably mounted therein, said posterior chamber containing gas at a pressure relatively low in comparison with the pressure of well fluids and in volume greater than twice the volume of hydraulic fluid which said first cylinder can hold; a third piston slidably mounted in a third cylinder to define in co-operation with said third cylinder at high pressure chamber containing hydraulic fluid in a volume greater than twice the volume of said first cylinder, said third piston having one side thereof exposed to the pressures of Well fluids whereby said high pressure chamber is maintained at pressures equal to that of the well fluids; a valve with four ports and a movable elementadapted either to connect the first port to the second and the third port to the fourth, or alternatively to connect the, first port to the fourth and the second to the third; conduits connecting said high pressure chamber to said first port, one end of said first cylinder to said second port, the other end of said first cylinder to said fourth port, and said anterior chamber to said third port, whereby said valve and conduits may, convey the pressure diflFerential between said high pressure and low pressure chambers to opposite sides of said first piston in alternative directions to activate said piston to movement in alternative directions; and a means for operating said valve to efiect either of said alternative pressure differential applications.

2. In an instrument adapted to be run in a well and having a retractable member therein, a hydraulic system for controlling said member comprising the combination of a hydraulic motor including a cylinder with a piston therein which is responsive to hydraulic fluid pressure diiferentials in either of two alternative directions, said piston being connected by a linkage to said controlled member whereby said motor drives and controls said member in its movement from one of its positions to the other; a low pressure chamber divided by a movable element therein into anterior and posterior, chambers, said posterior chamber containing gas at a pressure relatively low in comparison with the pressure of well fluids and in volume greater than twice the volume of hydraulic fluid which said cylinder can hold; a high pressure chamber substantially filled with hydraulic fluid; means for communicating the pressure of said well fluids to the hydraulic fluid in said high pressure chamber; a valve having conduit means for connecting said high pressure chamber and said low pressure chamber to said motor in either of two alternative manners, so that a pressure differential may be created in said motor in either of two alternative directions and cause said motor to move in either of two alternative directions; and a means for operating said valve means to effect connections in either of two alternative manners.

3. The invention defined in claim 2 wherein said valve and conduit means comprise a valve with four ports and a movable element adapted either to connect the first port to the second and the third port to the fourth, or alternatively to connect the first port to the fourth and the second to the third; a conduit connecting said high pressure chamber to said first port; a conduit connecting one end of said cylinder to said second port; a conduit connecting the other end of said cylinder to said fourth port; and a conduit connecting said third port to said anterior chamber.

4. In an instrument adapted to be run in a well and having a controlled member therein which is to be moved to either of two alternative positions during the operation of the instrument, a hydraulic system for controlling said controlled member comprising the combination of a hydraulic motor with a moving element responsive to hydraulic fluid pressure difierentials in either of two alternative directions, said moving element being connected by a linkage to said controlled member whereby said motor drives and controls said member in its movement from one of its positions to the other; a low pressure chamber containing a substantial quantity of gas at a pressure relatively low in comparison with the pressure of well fluids; a high pressure chamber containing hydraulic fluid; means for communicating the pressure of said well fluids to the hydraulic fluid in said high pressure chamber; a valve having conduit means for connecting said high pressure chamber and said low pressure chamber to said motor in either of two alternative manners, whereby a pressure dilferential may be created in said motor in either of two alternative directions and cause said motor to move in either of two alternative directions; and a means for operating said valve means to effect connections in either of two alternative manners.

5. In an instrument adapted to be operated in a high fluid pressure environment upon remote actuation and having a controlled member therein which is to be moved to either of .two alternative positions during the operation of the instrument, a hydraulic system for controlling said controlled member comprising the combination of a hydraulic motor with a moving element responsive to hydraulic fluid pressure differentials in either of two alternative directions, said moving element being connected by a linkage to said controlled member whereby said motor drives and controls said member in its movement from one of its positions to the other; a low pressure chamber containing a substantial quantity of gas at a pressure relatively low in comparison with the fluid pressure of the environment surrounding said instrument; a high pressure chamber containing hydraulic fluid; means for communicating the fluid pressure of said environment to the hydraulic fluid in said high pressure chamber; a valve having conduit means for connecting said high pressure chamber and said low pressure chamber to said motor in either of two alternative manners, so that a pressure differential may be applied to said motor in either of two alternative directions and cause the moving element in said motor to move in either of two alternative directions; and a means responsive to actuation externally of said environment for operating said valve means to eflect connections in each of said two alternative manners.

6. In an instrument adapted to be run in a well and having a retractable member therein, means for controlling said retractable member comprising the combination of a high pressure chamber containing hydraulic liquid; means for communicating the fluid pressure external of said instrument to the hydraulic liquid in said high pressure chamber; a low pressure chamber containing fluid including a substantial quantity of gas at normally much lower pressure than the pressure in said well external of said instrument; a motor responsive to liquid flow to produce mechanical power in either of two alternative directions, depending upon the direction of liquid flow through said motor; said motor being connectable through a valve and conduit means to said high pressure chamber and said low pressure chamber in either of two alternative ways, so that liquid may flow from the high pressure chamber to the low pressure chamber, passing through the motor in either of two alternative directions in response to the pressure differential between said two chambers; and a linkage connecting said motor to said retractable member whereby said retractable member is controlled by said motor.

7. In an instrument adapted to be run in a well and having a retractable member adapted to protrude therefrom, the combination of a first cylinder and first piston assembly wherein said first piston is positioned slidably within said first cylinder to define first and second chambers; a second cylinder and second piston assembly wherein said second piston is positioned slidably within said second cylinder so as to define an anterior chamber and a posterior chamber within said cylinder; at third cylinder and third piston assembly wherein said third piston is positioned slidably within said third cylinder, wherein said third piston has one side thereof exposed to the pressures of well fluids external of the instrument and wherein the second side of said piston co-operates with said first cylinder to define a third chamber; said second and third cylinders being each of volume at least twice that of said first cylinder; a valve having conduit means for connecting said third chamber into communication with said first chamber and said second chamber into communication with said anterior chamber, and for alternatively connecting said third chamber into communication with said second chamber and said first chamber into communication with said anterior chamber; means for activating said valve means to change from each of said alternate connections to the other of said alternative connections; and a linkage connecting said retractable member to said first piston, whereby said retractable member is moved in response to the movement of said first piston.

References Cited in the file of this patent UNITED STATES PATENTS 1,290,203 Honk Jan. 7, 191.9 2,290,479 Mercier July 21, 1942 2,622,334 Wiley Dec. 23, 1952 2,640,275 Boucher June 2, 1953

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