Hydraulic Device and Method for Locating and Sealing Holes or Cracks in Oil Well Production Tubing

Abstract

The invention relates to a hydraulic device for in situ hermetic sealing of holes, cracks or leaks from joints that occur in underground production tubing used for the extraction of oil, gas or other fluids. In particular, the invention relates to a device comprising an assembly including four sections comprising various securing and anchoring means, and to the method for moving the device in order to detect and locate the site of the leak and to position the device inside the fluid production tubing, such that it remains fixed in place and hermetically seals the damaged section of the production tubing, allowing normal production flow to be resumed.

Claims

1. A hydraulic device for in situ sealing of cracks and holes in the production tubing of oil wells, located underground, said device being assembled along 4 sections with a total length of 2.00 m to 3.00 m and a diameter of 70 to 80 mm, and it comprises: a) an upper section, comprising: 1 upper cylinder, and upper displacement means; b) an extension section, comprising: an upper piston, an upper sealing means located on the upper segment of the upper piston, 1 extension tube whose upper part holds the upper piston by means of 2 set screws, and whose lower part is coupled with a central section, and 1 lower adapter, to connect the lower part of the extension section to the central section; c) the central section, comprising: a central cylinder, lower displacement means, and, wherein the lower part of the central section is connected to a lower piston housing; and, d) a lower, comprising: the lower piston housing, whose lower part contains 2 set screws, 1 lower cylinder, 1 lower piston, a lower sealing means, 1 sliding cone, and anchoring means, comprising 1 cage, 2 wedges.

2. The hydraulic device as claimed in claim 1, wherein the upper cylinder is connected by its upper part to a Fishing Neck by means of a threaded joint and, by its lower part, to the extension section through a reduction.

3. The hydraulic device as claimed in claim 1, wherein the upper sealing means of the upper section comprises: 2 spacers, 2 retainer rubbers, 2 rubber retainers and 1 adjuster nut to adjust the retainer rubbers.

4. The hydraulic device as claimed in claim 3, wherein the retainer rubbers are shaped like a truncated cone, with the larger diameter placed upwards.

5. The hydraulic device as claimed in claim 1, wherein the upper piston at the extension section has an external diameter that gradually varies from top to bottom, featuring the larger diameter at the upper part, with a flange that acts as a stopper; next, there is a second segment where the piston diameter is reduced by a length similar to that of expansion joints, and the remaining segment, with an even smaller diameter, is introduced into the extension tube after going through the upper sealing means; and the lower segment of the piston is covered by a rupture disc, which is supported by a disc retainer.

6. The hydraulic device as claimed in claim 1, wherein the upper sealing means are located on the piston segment with the smaller diameter, and they comprise: 3 expansion joints attached to the upper end of the extension tube by an upper joint retainer.

7. The hydraulic device as claimed in claim 1, characterized by the fact that the extension tube has cutting set screws on its upper part, which hold the upper piston, and it features the lower adapter on its lower part, allowing it to couple with the central section.

8. The hydraulic device as claimed in claim 1, wherein the lower displacement means situated in the central section comprise 2 spacers, 2 retainer rubbers, and 1 rubber retainer.

9. The hydraulic device as claimed in claim 1, where the retainer rubbers are shaped like a truncated cone, with the larger diameter placed in opposite directions, upwards and downwards.

10. The hydraulic device as claimed in claim 1, wherein the lower cylinder of the lower section has two flow holes on its upper part, which communicate with the housing interior; and whose lower end features a rupture disc, held by 1 disc retainer.

11. The hydraulic device as claimed in claim 1, wherein the piston located in the annular space between the housing and the cylinder features a diameter that gradually varies along three segments: the first segment, adjusted to the housing; the second segment, slightly smaller and whose length is similar to the lower expansion joints; and the third segment, even smaller than the second one, which goes through the lower sealing means and enters the sliding cone.

12. The hydraulic device as claimed in claim 1, wherein the lower sealing means comprise: 3 expansion joints, whose position is set by 1 lower joint retainer at the lower segment of the lower piston.

13. The hydraulic device as claimed in claim 1, wherein the sliding cone is mounted on the lower end of the lower piston and slides between the lower joint retainer and the lower cylinder.

14. A method for in situ sealing of holes, cracks or leaks in joints, which exist in underground production tubing of oil wells, for the extraction of fluids like oil from the oil wells to the surface, characterized by comprising the following steps: I. displacement of the hydraulic device as claimed in claim 1. II. location of the hole or crack III. settling of upper section IV. settling of lower section V. completion of the hermetic sealing.

15. The method for in situ sealing of holes, cracks or leaks in the joints of production tubing as claimed in claim 14, wherein the displacement of the hydraulic device is performed by means of a driving liquid that is pumped from the surface and enters the device through the fishing neck, going through the upper cylinder until it gets pressurized in the rupture disc, thus forcing the hydraulic device to move downwards; through the interior of the production tubing and, at the same time, the fluid outside the hydraulic device causes the expansion of the retainer rubbers, controlling the movement and causing the fluid that is contained in the production tubing below the device to be forced to exit through the leak site on the production tubing, until the detection means or the retainer rubber that is now upside down surpasses the hole or crack, thus bringing the leak to an end.

16. The method for in situ sealing of holes, cracks or joints in the production tubing as claimed in claim 14, wherein, at the moment when the hole or crack is blocked, the pressure that is measured on the surface is increased up to 8273.76 KPa (1200 psi), which causes the cutting set screws of the hydraulic device to break, thus releasing the upper piston, which begins to go down through the inside of the extension tube at the extension section, and then goes into the interior diameter of the upper expansion joints and presses them against the interior walls of the production tube, leaving the upper section of the hydraulic device hermetically sealed and settled.

17. The method for in situ sealing of holes, cracks or leaks in the joints of production tubing as claimed in claim 14, wherein, after fixing the upper section of the device, the lower section is then fixed, for which purpose the pressure is increased up to 15,168.56 KPa (2200 psi), which causes the upper rupture disc at the upper section to break; next, the pressure is reduced up to its prior lower value and the pumped fluid flows downwards, through the extension tube at the extension section, in the central cylinder at the central section, and in the lower cylinder at the lower section, and exerts pressure on the lower rupture disc, after which the pressure of the fluid is increased in order to push it through the flow holes in the lower cylinder, until pressure is exerted on the lower piston and a pressure of 9,652.72 KPa (1400 psi) is reached, which causes the 2 lower cutting set screws to break, thus displacing the lower piston downwards, until it goes into the interior diameter of the lower expansion joints and presses them against the interior walls of the production tube, thus leaving the lower section of the hydraulic device hermetically sealed and settled.

18. The method for in situ sealing of holes, cracks or leaks in joints of the production tubing as claimed in claim 14, wherein, by increasing the pressure used to fix the interior section, the sliding cone is anchored, threaded to the lower piston, in the wedges through the inside of the Cage, thus leaving the lower section of the hydraulic device hermetically sealed and anchored against the walls of the production tubing.

19. The method for in situ sealing of holes, cracks or leaks in joints of production tubing as claimed in claim 14, wherein, after fixing the upper and lower sections of the hydraulic device for the sealing of holes, cracks or leaks, the settling of the hydraulic device is then verified and once verified, the lower rupture disc breaks, thus establishing communication between the lower, central, and upper cylinders, so that the field fluids may flow normally through the interior of the hydraulic device and the production tubing, in any direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0024] To apply the hydraulic device and the method to locate and seal holes or cracks in production tubing at oil wells, the following steps will be taken:

[0025] First Step: Before a sealing method is carried out, the technical traits to be met by the completion and the well to be intervened must be determined, which must comply with the following specifications: [0026] a) The oil lifting type, preferably by jet hydraulic pumping (JHP), natural flow (NF), or submersible electric pumping (SEP) (FIG. 1); [0027] b) the diameter of the production tubing [FIG. 1(03)] installed, which must be between 75 mm and 115 mm; [0028] c) having a settling nipple [FIG. 1(09)] and a flow sleeve in place [FIG. 1(04)] at the bottom of the production tubing. [0029] d) having the following data records in connection with the well and the completion: production flows, parameters of produced fluids, well bottom pressures, and operating pressures for artificial type lifting.

[0030] Second Step: Perform leak tests on the tubing

[0031] Once the well and completion information is available, a leak test will be performed on the production tubing [FIG. 1(03)] and, for this purpose, a valve must be installed at the bottom of the well, on the settling nipple [FIG. 1(09)], or in the circulation sleeve [FIG. 1(04)], such installation being usual and known in the state of the art. Once the valve is installed at the bottom of the well, the production tubing is then pressurized by pumping a fluid from the surface, at an increasing pressure within a range of 689.48 KPa (100 psi) to 27,939.03 KPa (4000 psi); if there comes a time when the pressure of the pumped fluid no longer increases, then the production tubing is hermetic; otherwise, if the pressure decreases, this would confirm the presence of a fluid leak through a hole or crack [FIG. 3(10)] in any section of the production tubing [FIG. 1(03)] towards the annular space [FIG. 1(05)]. Then, note the information relative to the flow of the fluid that runs through the annular space FIG. (1. 05), which corresponds to the flow of the fluid running through the hole or crack [FIG. 3(10)], using, for this purpose, a flow meter on the surface. The flow information is important in order to determine the characteristics of the hole or crack on the production tubing.

[0032] Third Step: Hermetic sealing method

[0033] Once the above steps have been carried out, and after confirming the existence of a hole or crack on the production tubing [FIG. 1(03)], the following method is then conducted, by using the innovative hydraulic device, as described in [FIG. 2], which is introduced and coupled to the production tubing until it becomes hermetically sealed:

[0034] The hydraulic device [FIG. 2] is hydraulically displaced from the surface at a pressure of 344.74 KPa (50 psi) through the production tubing interior, which is filled with the fluid used in the leak test previously described; when the device stops and the pressure increases, the location of the hole or crack [FIG. 4 (10)] may be detected, and this event occurs because the device can no longer move forward, as it has reached the level of the fluid column caught between the bottom valve and the level at which the hole or crack is situated; at this moment, the technician who is monitoring the operation on the surface proceeds to increase the hydraulic pressure so the device can be attached in that location [FIG. 5] and it creates a hermetic sealing between the body of the hydraulic device and the production tubing through the upper expansion joints [FIG. 4(20B)] and the lower expansion joints [FIG. 4(20D)], filling the hole or crack [FIG. 4(10)] that was detected in the production tubing [FIG. 4(03)] and thus allowing for the free circulation of fluids, with no leakage, between the well and the surface or vice versa, through the hydraulic device.

[0035] In order to run the above method, the following steps are taken: [0036] I. DISPLACEMENT OF THE HYDRAULIC DEVICE [0037] 1. The pumped fluid comes in through the Fishing Neck [FIG. 2(12)], it goes through the upper cylinder [FIG. 2(13A)], until it gets pressurized in the Rupture Disc [FIG. 3(34B)], thus forcing the Hydraulic Device to move downwards. [0038] 2. At the same time, the fluid outside the Hydraulic Device [FIG. 2] causes the expansion of the Retainer Rubbers [FIG. 3(15A)], which controls the downward movement of the hydraulic device. [0039] 3. Consequently, the existing fluid at the production tubes is progressively pushed by the hydraulic device [FIG. 2], as it is pressed downwards and forced to exit through the hole or crack [FIG. 3(10)] on the production tubing [FIG. 3(03)], until the detection means or the Retainer Rubber that is now inverted downwards [FIG. 4(15C)] surpasses the hole or crack, thus bringing the leak to an end. [0040] II. LOCATION OF HOLE OR CRACK AND SETTLING OF UPPER SECTION [0041] 1. At the moment when the hole or crack [FIG. 4(10)] is blocked, the pressure measured on the surface is increased until it reaches 8273.76 KPa (1200 psi), which causes the breakage of the Cutting Set Screws [FIG. 4(22B)], thus releasing the Upper Piston [FIG. 4(19B)], which begins to go down through the inside of the Extension Tube [FIG. 4(24B)] at the Extension Section, and then goes into the interior diameter of the upper Expansion Joints [FIG. 4(20B)] and presses them against the interior walls of the production tube [FIG. 4(03), leaving the Upper Section [FIG. 4] of the Hydraulic Device hermetically sealed and settled [FIG. 2]. [0042] III. SETTLING OF LOWER SECTION [0043] 1. To continue with the settling of the Lower Section, pressure is increased up to 15,168.56 KPa (2200 psi), which causes the upper Rupture Disc to break [FIG. 4(34B)] at the Upper Section, causing the fluid that is pumped from the surface to flow downwards through the Extension Tube [FIG. 4(24B)] at the Extension Section, in the Central Cylinder [FIG. 4(24B)] at the Central Section, and in the Lower Cylinder [FIG. 4(29D)] at the Lower Section, until it reaches the lower Rupture Disc [FIG. 4(34D)]. Then, pressure is reduced to its prior lower value. [0044] 2. The pressure of the fluid is increased in order to push it through the flow holes [FIG. 4(35D)] in the Lower Cylinder [FIG. 4(29D)], until pressure is exerted on the Lower Piston [FIG. 4(27D)] and a pressure of 9,652.72 KPa (1400 psi) is reached, which causes the 2 lower Cutting Set Screws to break [FIG. 4(22D)], thus displacing the Lower Piston [FIG. 4(24B)] downwards, until it goes into the interior diameter of the lower Expansion Joints [FIG. 4(20D)] and presses them against the interior walls of the production tube [FIG. 4(03), thus leaving the Lower Section [FIG. 4] of the Hydraulic Device hermetically sealed and settled. [0045] IV. ANCHORING OF SLIDING CONE [0046] 1. The last cited action causes the anchoring of the Sliding Cone [FIG. 4(31D)], which is threaded to the Lower Piston [FIG. 4(28D)], in the Wedges [FIG. 4(32D)] through the inside of the Cage [FIG. 4(33D)], thus leaving the Lower Section of the Hydraulic Device hermetically sealed and anchored [FIG. 2] against the walls of the Production Tubing [FIG. 4(03)]. [0047] V. HERMETIC SEALING COMPLETION [0048] 1. Pumping pressure is continuously increased up to 17237 KPa (2500 psi) in order to check the settling of the Hydraulic Device [FIG. 2]. Once this is verified, the lower Rupture Disc [FIG. 4(34D)] breaks, thus establishing communication between the lower [FIG. 5(29D)], central [FIG. 5(26C)] and upper cylinders [FIG. 5(13A)], so that the fluids may flow [FIG. 1(08)] normally through the interior of the Hydraulic Device [FIG. 2] and the production tubing, in any direction.