MXPA00002824A - Production fluid control device for oil/gas wells - Google Patents

Abstract

A device and method for selectively controlling the flow of production fluid through a tubing string (12) in an oil and gas well according to which a housing (24) is connected to a tubing string (12) for inserting into the well, and the well fluid is passed from the ground surface into the housing (24). The housing (24) is provided with a plug (56) to establish fluid pressure into the housing (24) to actuate a packer (16) and/or other ancillary devices. The plug (56) can be removed from the housing (24) by increasing the pressure of the well fluid in the housing (24) above a predetermined value, thus permitting the flow of production fluid from the formation zone, through the housing (24) and the tubing string (12), and to the ground surface.

Description

PRODUCTION FLUID CONTROL DEVICE FOR PETROLEUM / GAS WELLS BACKGROUND OF THE INVENTION The present invention relates to a fluid control device for use in an oil and / or gas well and, more particularly, to such a device for selectively controlling the flow of production fluid from a production formation adjacent to the well, through the well, and to the surface on land. In a typical oil and gas production well, a casing is provided to line the well and is provided with perforations adjacent to the formation to receive the production fluid. A pipe string is run into the tubing and has a smaller external diameter than the inner wall of the tubing to form a ring. A packer is placed in the ring to direct the production fluid to the lower end of the pipe string for upward passage through the pipeline for ground recovery. It is often advantageous, and sometimes necessary, to use hydraulically actuated packers and other auxiliary devices, especially when operating in deviated or horizontal well sections. For this purpose, the flow of production fluid to and through the pipe string is blocked, and the well fluid is introduced into the pipe string from the earth surface, to create a relatively high fluid pressure that is used to operate these devices. After this operation is complete, the pipe string must be opened to allow the flow of production fluid through the string and to the ground surface. Therefore, pumping plugs, or the like, are often provided in the pipe string, which normally block the flow of fluid through the string and which are ejected from the string when flow of the production fluid is desired. However, these plugs are relatively large and, when ejected, they must be either removed from the well borehole by spiral pipe or the like, which is extremely expensive, or left in the borehole, which can cause problems during the life of the well. Also, disk submarines have been used that incorporate a disk that normally blocks the flow of fluid through the pipe string and that breaks in response to a fluid pressure acting on it when flow is desired. However, these disk submarines suffer from the fact that the pressure that has to be applied to break the disk is often excessive and unpredictable. Therefore, other techniques have been devised to break the discs to allow fluid flow. For example, steel bars that are dropped into the well or run in a wire line or spiral pipe have been used. This has disadvantages because the broken disk forms debris in the hole borehole and, if that well has a deviated or horizontal section, a drop bar or a wire line run is highly unreliable. Still other techniques for selectively blocking the flow of production fluid through the pipe string involve fixed / recovered pipe plugs per wire line. However, these devices require a "profiled" submarine that has to be added to the pipe string and require the use of wire line intervention, as well as increased risk and costs. Therefore, what is needed is a relatively inexpensive and reliable device to selectively control the flow of production fluid through a pipe string in an oil and / or gas well that minimizes the amount of waste left in the drilling of the well. well but can still be activated with a predictable and relatively low amount of fluid pressure. Also what is needed is a device of the above type that does not require a profile submarine or any drive device for dropping into the pipe string or running into the string on a wire line or spiral pipe. SUMMARY OF THE INVENTION The present invention, accordingly, it is directed to a device for selectively controlling the flow of production fluid through a string of pipe in an oil and gas well according to which one end of a housing is connected to a pipe string for insertion into the well, and the well fluid is passed from the ground surface to the end of the housing. The other end of the housing is closed to establish wellbore fluid pressure in the housing to drive a packer and / or other auxiliary devices. The other end of the housing can be opened by increasing the pressure of the well fluid in the housing over a predetermined value, thus allowing the flow of production fluid from the formation, through the housing and the pipe string, and to the ground surface . Several advantages are a result of the device and the method of the present invention. For example, they are relatively cheap and reliable, but they still minimize the amount of waste left in the well drilling. Also, the device can be activated with a relatively low and predictable amount of fluid pressure, and does not require a profile submarine or any drive device that should be dropped into the pipe string or run into the string in wire line or spiral pipe. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partially elevational view, partly in sections, depicting an installation in an oil and / or gas well, including the device of the present invention. Figures 2 and 3 are vertical views in sections of the device of the present invention, outlining two modes of operation of the device. Figures 4 and 5 are views identical to those of Figures 2 and 3, respectively, but outlining an alternate embodiment of the device of the present invention. Description of the Preferred Embodiment Form The well fluid control device of the present invention is designed to be used within the hole in an oil and / or gas well sketched in Figure 1. Reference number 10 refers to, in general, to a well casing that lines the hole and receives a string of pipe 12 having an outside diameter that is smaller than that of the casing to define a ring 14 between the pipe string and the casing. The pipe string 12 can be lowered into the housing 10 from the ground surface in any conventional manner such as by using a wire line, spiral pipe, or the like. A packer 16 is disposed in the ring 14 and extends around a lower portion of the pipe string 12, as seen in Figure 1. The packer 16 is preferably hydraulically actuated and as is conventional, will not be described in detail . A plurality of perforations 10a are formed through the tubing 10 below the end of the pipe string 12. The perforations 10a allow production fluid from a forming zone F to flow into the housing 10 and through the pipe string to the ground surface, in a way that will be described. The control device of the present invention is referred, in general, by the reference number 20, and is attached to the lower end portion of the pipe string 12. The control device 20 is adapted to selectively control the flow of the production fluid through the pipe string 12 and the land surface, and to allow fluid from the wellbore from the land surface to be introduced into the pipe string 12 and pressurized sufficiently to drive the packer, and any auxiliary devices. For this purpose, and with reference to Figure 2, the control device 20 comprises a submarine 22, which is threaded internally in its upper end portion 22a, as seen in Figure 2, to mate with an end portion. lower threaded externally, corresponding, of pipe string 12 (figure 1). The control device 20 also includes a tubular housing 24 having an internally threaded upper end portion 24a, threadably engaging a correspondingly externally threaded lower end portion 22b of the submarine 22. A plurality of fixed screws 26, one of which is shown in Figure 2, is angularly spaced around the circumference of the upper end portion 24a of the housing 24 and extends through the aligned opening in the aforementioned end portion and the lower end portion 22b of the submarine 22, to secure the submarine to the accommodation. A seal ring 28 extends between an outer surface portion of the submarine 22 and a corresponding internal surface portion of the housing 24. A lower submarine 30 is also provided, which has an internally threaded upper end portion 30a that threadably links a correspondingly externally threaded lower end portion 24b of the housing 24. A plurality of fixed screws 32, one of which is shown in Figure 2, is angularly spaced around the circumference of the upper end portion 30a of the lower sub. and extends through the aperture aligned in the aforementioned end portion and the lower end portion 24b of the housing 24, to secure the connection between the submarine and the housing. A seal ring 34 extends between an outer surface portion of the housing 24 and a corresponding inner surface portion of the submarine 30. The lower end portion of the lower submarine 30 is externally threaded so as to allow internally threaded submarines of auxiliary equipment (not shown) are attached to the device 20 as needed. A tubular piston 40 is slidably mounted in the housing 24 and its outer surface is stepped to define an upper end portion 40a, an intermediate portion 40b extending just below the upper end portion, and a portion 40c extending from the intermediate portion 40b to the lower end of the piston. The outer diameter of the intermediate portion 40b is larger than the diameter of the portions 40a and 40c, and a pair of axially spaced seal rings 42a and 42b extends between the outer surface portion of the intermediate portion 40b and the surface portions. of the housing 24. The lower end of the piston 40 tapers to a relatively sharp point for reasons that will be described below. A ring 46 is disposed in a space defined between the outer surface of the upper end portion 40a of the piston 40 and the corresponding internal surface of the housing 24. The ring 46 receives a plurality of angularly spaced shear stress pins 48 extending to through aligned openings in the ring 44 and the upper end portion of the piston 40. The shear pins 48 in this manner normally retain the piston 40 in its upper position shown in Figure 2, but are adapted to be cut in response to a predetermined shear force applied thereto to release the piston and allow sliding movement of the piston downwardly in the housing 24, as will be explained. A plurality of angularly spaced apertures 40d, one of which is shown in the drawings, extends through the upper end portion 40a of the piston 40 just below the openings receiving the shear pins 48, for reasons that they will also be explained. The inner surface of the housing 24 is stepped so that the inner diameter of its lower portion is smaller than that of its upper portion to define an annular chamber 50 between the inner surface of the upper portion of the housing 24 and a corresponding external surface of the piston 40. The relatively large diameter intermediate portion 40b of the piston 40 defines the upper limit of the chamber 50., and the reduced diameter portion of the housing 24 defines its lower limit. The chamber 50 accommodates the movement of the intermediate portion 40b of the piston 40 during its downward movement. A seal ring 52 extends between the outer surface portion of the portion 40c of the piston and a corresponding inner portion of the reduced diameter portion of the housing 24. In this manner, the chamber 50 extends between the rings of seal 42b and 52 to isolate the fluid chamber and to maintain the pressure in the chamber at atmospheric pressure for reasons that will be described later. The lower submarine 30 has a stepped internal surface defining a shoulder that receives a rupturable disc 56, and a seal ring 58 extends between the shoulder and the disc. The disc 56 is made of a material capable of breaking, such as glass, which is adapted to break when impacted by the sharpened bottom end of the piston 40 with sufficient force. The end of the housing 24 abuts the disc 56, and a seal ring 60 is disposed between the aforementioned end and the disc. A seal ring 62 extends between the outer surface of the disk 56 and the corresponding internal surface of the submarine 30. The disk 56 is capable of withstanding relatively large differential pressures acting on its respective upper and lower surfaces by much in excess of the magnitude of the force required to cut the pins 48, as will be described. In operation, a well fluid is introduced into the tubing 12 from the earth surface at a pressure sufficient to block the flow of production fluid from the forming zone F (Figure 1) through the perforations 10a and into the tubing 10. When it is desired to recover the production fluid, the pipe string 12 is run into the casing 10 with the device 20 attached to the lower end of the string, and with the packer 16 provided in a section of the string just above the device. 20. The presence of the disk 56 in the lower end portion of the device 20 allows well fluid from the earth surface to be introduced into the pipe string 12 at an increased pressure to establish a hydrostatic head to allow the packer 16 and / or any auxiliary devices are hydraulically fixed in a conventional manner. During this operation, the pressure of the well fluid in the device 20 acts on the upper end of the piston 40 in a downward direction and on the lower end of the piston in an upward direction. Since the annular surface area of the upper end of the piston 40 is larger than the area of its lower end annular surface, a differential force is established which applies a shearing force to the pins 48. However, the pins 48 are designed to normally resist the force and thus maintain the piston in its upper, static position of Figure 2. This increased fluid pressure in the device 20 is controlled so that the resulting differential pressure across the disc 56 caused by the said pressure acting on the upper surface of the disk 56, and the well fluid in the ring 14 acting on the lower surface of the disk, does not exceed the design limit of the disk. When the packer 16 and any auxiliary devices have been set according to the above and it is then desired to recover production fluid from the forming zone F, the pressure of the well fluid in the pipe string 12 is increased. Since the upper end surface of the piston 40 has a greater area than its lower end, the shear force applied to the pins 48 will be increased until the pins are cut, the openings 40d increasing the volume of the available well fluid to act on the upper surface of the piston 40. The piston 40 is thus forced down and its sharp lower end hits the disk 56 with sufficient force to tear it apart. It is noted that the relatively low atmospheric pressure existing in the chamber 50 does not prevent this downward movement of the piston 40 and that the previous increase in the hydrostatic head is selected so that the disk 56 can withstand the resulting differential pressure acting on its surfaces. upper and lower. The pressure of the well fluid in the pipe string 12 is then reduced as necessary to allow the well fluid in the ring, and then the production fluid from the formation zone F, flows through the device 20 and the pipe string 12 to the ground surface and are recovered. The device 20 in this way enjoys various advantages. For example, it is relatively inexpensive and reliable, but can still withstand a large magnitude of differential pressure of fluid and be activated with a relatively low magnitude of fluid pressure in a predictable manner. Also, the amount of waste left in the well bore is minimized, since the material used in the rupturable disk 56 is such that, once broken by the piston 40, it is reduced to small fragments or particles that may be fluid or circulated from the well. In addition, the device 20 does not restrict the internal diameter of the well bore and thus allows other tools to pass through and does not require a profile submarine or any drive device to be dropped into the pipe string or run towards the string in wire line or spiral pipe. The embodiment of Figures 4 and 5 is similar to the embodiment of Figures 2 and 3 and the same identical component reference numbers are given. According to the embodiment of Figures 4 and 5, a device 20 'is provided, which is identical to the device 20 of the embodiment of Figures 2 and 3 with the exception that, in the first of these devices, a plurality of angularly spaced gates is provided, one of which is shown by the reference numeral 24c in FIGS. 4 and 5, through the wall of the housing 24. The gates 24c are located axially relative to the housing 24. so that they register with the lower portion of the chamber 50 when the piston 40 is retained in its upper, static position by the shear force pins 48, as shown in Figure 4. In this manner, the well fluid before mentioned that it is initially in the ring 14 to maintain the production fluid in the formation zone F, as discussed above, will enter the chamber 50 through the gates 24c and exert a directed pressure to up against the lower annular surface of the relatively large diameter portion 40b of the piston 40.

As in the previous embodiment, the upper surface of the piston 40 has a larger surface area than the lower surface due to the relatively large diameter portion 40b. Therefore, there is a downward force caused by the well fluid inside the housing 24 acting on the upper surface of the piston 40, as described above, and an upward force caused by the well fluid in the well. interior of the housing acting on the lower surface of the piston, also as described above. In addition, there is an additional upwardly directed force by the well fluid in the ring 14 acting on the lower annular surface of the relatively large diameter portion 40b of the piston. Also, as in the previous embodiment, the shear pins 48 are designed to be cut at a predetermined shear force applied to them based on the difference of the aforementioned forces acting on the piston 40. However, in this embodiment, the shearing force may be much smaller than that of the embodiment of Figures 2 and 3, due to the presence of the above-mentioned directed upward force. Otherwise, the operation of the device 20 'is identical to that of the device 20 of the embodiment of FIGS. 2 and 3. The device 20' of the embodiment of FIGS. 4 and 5 thus enjoys all the advantages of the device 20 of the embodiment of FIGS. 2 and 3 and, in addition, the magnitude of the shear force required to cut the pins 48, and therefore drive the piston 40 of the previous device, is much lower than the device mentioned last. It will be understood that variations of the foregoing can be made without departing from the scope of the invention. For example, although the pipe string 12 and the devices 20 and 20 'are shown to extend vertically, it will be understood that this is solely for the purpose of exemplifying and that, in actual use, they may extend at an angle to the vertical. Therefore, the use of the terms "upper", "lower", "upward", "downward", and the like, is for illustrative purposes only and does not limit the specific orientation and position of any of the components before. discussed. It will be understood that other modifications, changes and substitutions are intended in the above disclosure and, in some cases, some aspects of the invention will be employed without a corresponding use of other aspects. Accordingly, it is appropriate that the appended claims be interpreted broadly and in a manner congruent with the scope of the invention.

Claims (11)

1. CLAIMS 1. A device for controlling the flow of production fluid from a formation zone in an oil and / or gas well to the ground surface, the device comprising: a housing adapted to be connected at one end to a string of pipe for insertion into the well and forming a ring between the outer surface of the housing and the inner surface of the well, said end of the housing being open to receive well fluid from the earth surface; a plug disposed at the other end of the housing to allow the increase in the pressure of the well fluid in the housing; a piston disposed in the housing - a plurality of shear pins attached to the piston to normally retain the piston in the housing, the shear stress pins responding to the wellbore fluid pressure in the housing exceeding a predetermined value for stress cutting to allow sliding movement of the piston in the housing against the plug to remove the cap from the housing and open the other end of the housing to allow the flow of production fluid from the formation zone, through the housing and the pipe string and the surface of the earth; a packer extending in the ring, that portion of the ring extending between the packer and the formation zone containing well fluid under pressure to normally maintain the production fluid in the formation zone; and a gate defined in the housing wall to allow said well fluid to enter the housing and act against the piston.
2. 2. A method for controlling the flow of production fluid from a formation zone in an oil and / or gas well to the earth surface, the method comprising the steps of: connecting one end of a housing to a pipe string for insertion in a vertical orientation to the well; passing well fluid from the ground surface towards the mentioned end of the housing; normally closing the other end of the housing to create a well fluid pressure in the housing; retaining a piston in the housing so that the well fluid in the housing acts on the respective ends of the piston, the surface area of the upper end of the piston being greater than the surface area of the lower end of the piston so that the fluid acts on the respective ends of the piston to create a differential force; the piston sliding down the housing in response to the differential force exceeding a predetermined value to open the other end of the housing and thus allowing the flow of production fluid from the formation zone through the housing and the pipe string and the ground surface; forming a ring between the outer surface of the housing and the inner surface of the well; fix a packer on the ring; maintaining pressure well fluid in that portion of the ring that extends between the packer and the formation zone to normally maintain the production fluid in the formation zone; and allowing said well fluid to enter the housing and act against the piston to change the differential force.
3. 3. A method for controlling the flow of production fluid from a formation zone in an oil and / or gas well to the earth surface, the method comprising the steps of introducing a fluid into the well to normally prevent the flow of oil. production fluid from the formation zone, insert a pipe string including a packer and housing into the well, run well fluid from the ground surface towards one end of the housing, close the other end of the housing to create a pressure of well fluid in the housing to fix the packer in the ring between the pipe string and the well wall, increase the pressure of the well fluid in the housing sufficiently to open the other end of the housing and thus allow the flow of production fluid from the formation zone through the housing and the pipe string and the land surface.
4. 4. The method of claim 3, comprising the steps of retaining a piston in the housing, the increased pressure well fluid in the housing releasing the piston and sliding the piston in the housing against the plug to open the housing.
5. The method of claim 4, wherein a plug closes the other end of the housing and the piston fractures the plug.
6. The method of claim 4, wherein the well fluid in the housing acts on the respective ends of the piston with a force corresponding to the respective areas of the surfaces of the mentioned ends, where the surface area of one of the Piston ends is greater than the surface area of the other end of the piston to create a differential force, and where the piston slides in response to the differential force exceeding a predetermined value.
7. The method of claim 6, wherein the housing and the piston extend substantially vertically, the surface of the upper end of the piston having a greater area than the surface of the lower end of the piston so that the piston slides substantially downwardly in the accommodation.
8. 8. A device for controlling the flow of production fluid from a formation zone in an oil and / or gas well to the ground surface, the device comprising: a housing adapted to be connected at one end to a string of pipe for insertion into the well, the aforementioned end of the housing being open to receive well fluid from the ground surface; a rupturable plug that extends into the housing and closes the other end of the housing that is being closed to allow the pressure of the well fluid to accumulate in the housing; and a piston normally retained in the housing and having a sharp end, the piston responding to the pressure of the well fluid in the housing exceeding a predetermined value to slide in the housing towards the plug so that the sharpened piston end fractures the piston. material susceptible to rupture of the cap to open the other end of the housing and allow the flow of production fluid from the formation zone, through the housing and the pipe string and to the ground surface.
9. The device of claim 8, further comprising a plurality of shear pins connected to the piston for normally retaining the piston in the housing, the shear stress pins responding to the wellbore fluid pressure in the housing exceeding the value predetermined for shear stress to allow sliding movement of the piston.
10. 10. A method for controlling the flow of production fluid from a formation zone in an oil and / or gas well to the ground surface, the method comprising the steps of: connecting one end of a housing to a pipe string for insertion into the well; passing well fluid from the ground surface towards the mentioned end of the housing; closing the other end of the housing with a plug liable to break to create a well fluid pressure in the housing; and providing a piston having a sharp end in the housing and adapted to respond to the pressure of the well fluid in the housing exceeding a predetermined value and to slide in the housing to its sharp end fracture the plug to open the other end of the housing. housing to allow the flow of production fluid from the formation zone through the housing and the pipe string and to the ground surface. The method of claim 10, further comprising the step of retaining the piston in the housing by a plurality of shear pins, the shear stress pins responding to the wellbore fluid pressure in the housing exceeding the predetermined value for shear stress to allow sliding movement of the piston.