Ultra-deep ultra-high pressure gas well oil testing pipe column and testing method

Abstract

The invention belongs to the technical field of oil and gas exploitation, and discloses an ultra-deep ultrahigh-pressure gas well oil testing pipe column and a testing method.The ultra-deep ultrahigh-pressure gas well oil testing pipe column comprises a perforating gun set, a screen pipe, a matched perforating tool, a matched underground testing tool, a first testing oil pipe, an underground safety valve and a second testing oil pipe which are sequentially connected to a well opening from bottom to top; a hydraulic control pipeline is arranged on the outer wall of the second test oil pipe; each of the second test oil pipe and the first test oil pipe comprises a plurality of oil pipes. The pipe column structure drives the subsurface safety valve to enter a well, a barrier is added in an oil pipe, when a wellhead is complex during testing, the subsurface safety valve can be closed in a wellhead pressure relief mode, underground well closing is achieved, and ground safety is guaranteed. After the test is finished, the subsurface safety valve is closed, gas above the safety valve in the oil pipe is discharged, gas is prevented from entering the well killing pump to cause gas blockage, and equipment safety is guaranteed. According to the invention, the oil testing of the ultra-deep and ultra-high pressure gas well can be realized, and the safety and high efficiency of the oil testing are ensured.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil and gas exploitation, and particularly relates to an ultra-deep and ultra-high pressure gas well testing pipe column and a testing method. BACKGROUND

[0002] The lower group of blocks in some areas has complex combined geological engineering conditions, has the characteristics of ultra-deep (>8000m), high temperature (170.13℃), and ultra-high pressure (171.78MPa), and compared with other oilfields, the indexes such as formation pressure, pressure coefficient, wellhead flow pressure, and shut-in pressure have reached the highest level at home and abroad, the long-term testing, high-efficiency well killing, and closed operation are difficult, the well control risk is high, and the safe and efficient oil testing is faced with great difficulties.

[0003] The existing testing methods mainly have two sets of testing pipe column structures of "two valves and one packer" and "light oil pipe". The perforating testing combined pipe column of "two valves and one packer" has two independent well barriers, but the pipe column structure is complex, many downhole tools such as testing valves, pressure gauges, and packers are put into the well, many conversion joints exist, the perforating detonation mechanism is unclear, the packer core shaft is prone to break off under the conditions of high temperature and high pressure, and other downhole complexities exist. The perforating testing pipe column of "light oil pipe" has only one well barrier, the structure is simple, the perforating detonation space is large, and the complexity probability is small, but the formation pressure is high, the wellbore has the risk of overpressure, and the well killing operation is difficult, and the well control risk is high. SUMMARY

[0004] In view of the problems existing in the prior art, the application provides an ultra-deep and ultra-high pressure gas well testing pipe column and a testing method, which can realize the oil testing of the ultra-deep and ultra-high pressure gas well and ensure the safety and efficiency of the oil testing.

[0005] To achieve the above technical purposes, the application adopts the following technical solutions:

[0006] An ultra-deep and ultra-high pressure gas well testing pipe column, comprising, from bottom to top, a perforating gun group, a screen pipe, a matching perforating tool, a matching downhole testing tool, a first testing oil pipe, a downhole safety valve, and a second testing oil pipe connected to the wellhead in sequence.

[0007] The outer wall of the second testing oil pipe is provided with a hydraulic control pipeline.

[0008] The second testing oil pipe and the first testing oil pipe each comprise a plurality of oil pipes.

[0009] Further, the outer wall of the second testing oil pipe is provided with a hydraulic control pipeline fixed by a downhole safety valve clamp.

[0010] Meanwhile, the application also provides an ultra-deep and ultra-high pressure gas well testing method, which adopts the ultra-deep and ultra-high pressure gas well testing pipe column as described above and comprises the following steps:

[0011] Step S1: install the wellhead blowout preventer and pass the pressure test according to the design requirements, lower the super deep and super high pressure gas well testing string in the oil testing fluid according to the string structure requirements in the oil testing engineering design, and when the super deep and super high pressure gas well testing string is lowered to the vicinity of the perforation position, carry out depth calibration, short connection arrangement, tubing hanger setting, blowout preventer unloading, gas wellhead installation and pressure test according to the design requirements;

[0012] Step S2: pressurize the wellhead according to the design requirements and stabilize at the rated opening pressure, transmit the pressure to the downhole safety valve through the hydraulic control pipeline, open the downhole safety valve, and open the gas testing channel of the super deep and super high pressure gas well testing string;

[0013] Step S3: continuously pressurize in the oil testing fluid with the liquid surface at the wellhead to the design value, carry out tubing transmission perforation operation, perforate the oil testing section, and carry out hole density, phase angle and hole arrangement according to the design;

[0014] Step S4: carry out liquid discharge and testing: discharge liquid according to the design requirements or use a choke; after perforation is confirmed on site, shut in and observe, calculate the formation pressure after the wellhead pressure is stable within the set range value, predict the maximum wellhead shut-in pressure; during the production test, the production pressure drop is required to be less than the predicted sand production pressure drop; accurately record the production, pressure and sample analysis data during the production test;

[0015] Step S5: shut in and exhaust: after the gas testing is completed, depressurize the wellhead according to the design requirements, release the pressure in the hydraulic control pipeline, close the downhole safety valve, and then exhaust the high pressure gas above the wellhead through the surface pipeline;

[0016] Step S6: well killing and string lifting: after the wellhead oil pressure is reduced to 0, start the pump to kill the well, select the set density of the well killing fluid according to the formation pressure after the perforation test, and carry out the replacement operation after well killing.

[0017] Further, in step S1, all the oil pipes into the well are passed through the corresponding size of the pipe through gauge.

[0018] Further, in step S1, the speed of lowering the string is within a set range.

[0019] Further, in step S1, before the downhole safety valve is lowered, the hydraulic pipeline of the downhole safety valve is pressure tested, the pressure test value is the rated opening pressure, and whether the downhole safety valve is normally opened is verified.

[0020] The lowering speed is controlled during the downhole safety valve lowering, and the hydraulic control pipeline is fixed on the oil pipe coupling by the safety valve clamp every time an oil pipe is lowered in the second testing oil pipe.

[0021] Further, in step S3, the design value is -10-15 MPa in the oil testing fluid with the liquid surface at the wellhead.

[0022] Furthermore, in step S3, the perforation uses a dual detonator, with a delayed perforation at the head and a non-delayed perforation at the bottom. The upper detonation pressure is lower than the bottom detonation pressure. If the head detonator fails to detonate, the tail detonator will be detonated to perform the perforation operation.

[0023] Furthermore, in step S3, the bottom detonation pressure is 20 MPa.

[0024] Furthermore, in step S4, the well is shut in three times with controlled pressure drainage via surface pipeline, with each drainage consisting of 3-5 cubic meters of fluid. This process is used to determine the properties of the formation fluid and its seepage capacity, providing basic data for subsequent trial production, testing, and formation sealing.

[0025] Furthermore, in step S6, firstly, the oil tubing above the safety valve on the surface is filled with kill fluid using a pump truck. Then, the wellhead is pressurized according to the design requirements and stabilized at the rated opening pressure. The pressure is transmitted to the downhole safety valve through the hydraulic control pipeline. The downhole safety valve opens, establishing oil-casing connection and starting the circulating kill operation.

[0026] After the circulating well control is stable until the oil casing pressure drops to 0, the open well observation time should be greater than the operation cycle of one wellhead replacement device. After confirming that there are no abnormalities, the well should be circulated and washed again for more than 1.5 times the wellbore volume. Only if there are no abnormalities can the replacement operation be carried out.

[0027] Furthermore, in step S6, when selecting a kill fluid of a set density for kill, the volume of the kill fluid of the set density is twice the wellbore volume.

[0028] Furthermore, in step S6, during the replacement process, the oil / gas tree gate valve is fully opened to keep the liquid level at the wellhead;

[0029] After removing the wellhead gas tree, installing the blowout preventer, and passing the pressure test according to the design requirements, pull out the perforation test string. Before tripping out of the well, prepare a combination of internal blowout preventers such as plug valves and blowout preventers, and ensure that the outer diameter of the blowout preventer matches the gate size of the blowout preventer.

[0030] The amount of kill fluid injected should match the amount of tubing removed during the tripping operation. If the amount of kill fluid injected is less than the required amount, the tripping operation should be stopped and the well shut in for observation.

[0031] If the oil casing pressure does not rise and there is no overflow, the cause should be identified and eliminated before the tubing string can be raised or lowered.

[0032] Once all tubing has been removed, the oil testing operation is complete.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] This invention provides an ultra-deep, ultra-high pressure gas well testing string and testing method, capable of meeting the testing requirements of ultra-deep, ultra-high pressure gas wells with formation pressure >170MPa and wellhead shut-in pressure >140MPa, while ensuring safe and efficient testing. The string structure includes a downhole safety valve, adding an extra barrier within the tubing. When encountering wellhead complexity during testing, the downhole safety valve can be closed via wellhead pressure relief, achieving downhole shut-in and ensuring surface safety. After testing, closing the downhole safety valve releases gas above the safety valve in the tubing, preventing gas from entering the kill pump and causing gas blockage, thus ensuring equipment safety. This invention represents the first application of its kind in the field of ultra-deep, ultra-high pressure gas well testing, and has a significant impact on the field of strategic advanced reserve technology. For a considerable period in the future, this invention will provide crucial support for safe and efficient testing in the ultra-deep exploration field. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the ultra-deep and ultra-high pressure gas well test tubing string according to an embodiment of the present invention;

[0036] Explanation of markings in the diagram:

[0037] 1-Perforation chamber assembly; 2-Screen pipe; 3-First test tubing; 4-Downhole safety valve; 5-Second test tubing; 6-Downhole safety valve clamp; 7-Hydraulic control line. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0040] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0041] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0042] To better understand the purpose, structure, and function of this invention, the following detailed description of an ultra-deep, ultra-high pressure gas well testing string and testing method is provided in conjunction with the accompanying drawings.

[0043] Example 1

[0044] This invention provides a test tubing string for an ultra-deep and ultra-high pressure gas well, comprising, from bottom to top, a perforation gun assembly 1, a screen pipe 2, matching perforation tools, matching downhole testing tools, a first test tubing 3, a downhole safety valve 4, and a second test tubing 5 connected to the wellhead;

[0045] The outer wall of the second test tubing 5 is equipped with a hydraulic control line 7 that is fixed by a downhole safety valve clamp 6.

[0046] Both the second test tubing 5 and the first test tubing 3 consist of multiple tubing.

[0047] Example 2

[0048] This invention provides a testing method for ultra-deep and ultra-high pressure gas wells, using the ultra-deep and ultra-high pressure gas well testing tubing string from Example 1, and includes the following steps:

[0049] Step S1: Install the 140MPa wellhead blowout preventer and test it to pass the pressure test according to the design requirements. According to the tubing structure requirements in the oil testing project design, lower the ultra-deep and ultra-high pressure gas well test tubing in the test fluid. When the ultra-deep and ultra-high pressure gas well test tubing is lowered to near the perforation position, perform depth calibration, short connection, set the tubing, remove the blowout preventer, install the gas production wellhead, and test it to pass the pressure test according to the design requirements.

[0050] Step S2: Pressurize the wellhead according to the design requirements and stabilize it at the rated opening pressure. Transmit the pressure to the downhole safety valve 4 through the hydraulic control line 7. The downhole safety valve 4 opens, and the gas testing channel of the ultra-deep and ultra-high pressure gas well test string is opened.

[0051] Step S3: Continuously pressurize the test fluid at the wellhead to the design value, perform tubing transfer perforation operation, perforate the test section, and execute the perforation density, phase angle, and perforation pattern according to the design.

[0052] Step S4: Drainage and Testing: Drain fluid according to design requirements or using a 2.0mm nozzle; after confirming perforation on-site, shut in the well and observe for at least 24 hours. Once the wellhead pressure has stabilized, calculate the formation pressure and predict the maximum wellhead shut-in pressure to provide support for the safety of the tubing string during the oil testing period; during the trial production period, it is required to control the production pressure differential to be less than the predicted sand production pressure differential, strengthen monitoring, and use large nozzles with caution; during the trial production period, accurately record production, pressure, and complete sample analysis data;

[0053] Step S5: Well shut-in and venting: After the gas test is completed, the wellhead is depressurized according to the design requirements to release the pressure in the hydraulic control line 7, the downhole safety valve 4 is closed, and then the high-pressure gas from the downhole safety valve 4 to the wellhead is discharged through the surface pipeline.

[0054] Step S6: Killing the well and pulling the tubing string: After the wellhead oil pressure drops to 0, start the pump to kill the well. Based on the formation pressure tested after perforation, select the kill fluid with the set density to kill the well. After killing the well, perform the replacement operation.

[0055] In step S1, all tubing entering the well must be cleaned using the appropriate gauge.

[0056] In step S1, the speed of lowering the tubing string must be within the set range to avoid premature perforation or other complex downhole situations caused by pressure surges.

[0057] In step S1, before the downhole safety valve 4 is lowered, the hydraulic pipeline of the downhole safety valve needs to be pressure tested. The test pressure value is the rated opening pressure to verify whether the downhole safety valve 4 is opening normally. During the lowering of the downhole safety valve 4, the lowering speed needs to be controlled. For each oil pipe in the second test oil pipe 5, the hydraulic control pipeline 7 needs to be fixed to the oil pipe coupling with the safety valve clamp 6.

[0058] In step S3, the test fluid with the liquid level at the wellhead is continuously pressurized to the design value, which is a negative pressure of 10-15 MPa.

[0059] In step S3, the perforation should be carried out using a dual detonator, with a delayed perforation at the head and a non-delayed perforation at the bottom. The upper detonation pressure should be 20 MPa lower than the bottom detonation pressure. If the head detonator fails to detonate, the tail detonator will be detonated to carry out the perforation operation.

[0060] In step S3, the bottom detonation pressure is 20 MPa.

[0061] In step S4, the well is shut in three times with controlled pressure drainage via surface pipeline, with each drainage consisting of 3-5 cubic meters of fluid. This process is used to determine the properties of the formation fluid and its seepage capacity, providing basic data for subsequent trial production, testing, and formation sealing.

[0062] In step S6, firstly, the tubing above the safety valve on the surface is filled with kill fluid using a pump truck. Then, the wellhead is pressurized according to the design requirements and stabilized at the rated opening pressure. The pressure is transmitted to the downhole safety valve 4 through the hydraulic control line 7. The downhole safety valve 4 is opened to establish oil-casing connection and start the circulation kill operation. After the circulation kill is stable until the oil-casing pressure drops to 0, the open well observation time should be greater than the operation cycle of one wellhead replacement device. After confirming that there are no abnormalities, the well is circulated and flushed again for more than 1.5 times the wellbore volume. If there are no abnormalities, the replacement operation can be carried out.

[0063] In step S6, when selecting a kill fluid of a set density for kill, the volume of the kill fluid of the set density is twice the wellbore volume.

[0064] In step S6, during the replacement process, the oil (gas) tree gate valve is fully opened to keep the fluid level at the wellhead.

[0065] After removing the wellhead gas tree, installing the blowout preventer, and passing the pressure test according to the design requirements, pull out the perforation test string. Before tripping out of the well, prepare a combination of internal blowout preventers such as plug valves and blowout preventers, and ensure that the outer diameter of the blowout preventer matches the gate size of the blowout preventer.

[0066] The amount of kill fluid injected should match the amount of tubing removed during the tripping operation. If the amount of kill fluid injected is less than the required amount, the tripping operation should be stopped and the well shut in for observation.

[0067] If the oil casing pressure does not rise and there is no overflow, the cause should be identified and eliminated before continuing the tubing string operation. The oil testing operation is complete once all tubing strings have been pulled out.

Claims

1. A test tubing string for ultra-deep and ultra-high pressure gas wells, characterized in that, It includes, from bottom to top, the perforating gun assembly, screen pipe, matching perforating tools, matching downhole testing tools, first test tubing, downhole safety valve, and second test tubing connected to the wellhead; The outer wall of the second test oil pipe is equipped with hydraulic control lines; Both the second test tubing and the first test tubing consist of multiple tubing sections.

2. The ultra-deep, ultra-high pressure gas well testing string according to claim 1, characterized in that, The outer wall of the second test tubing is equipped with a hydraulic control line secured by a downhole safety valve clamp.

3. A testing method for ultra-deep and ultra-high pressure gas wells, characterized in that, The method of using the ultra-deep and ultra-high pressure gas well testing string as described in claim 1 or 2 includes the following steps: Step S1: Install the blowout preventer at the wellhead and test it to pass the pressure test according to the design requirements. According to the tubing structure requirements in the oil testing project design, lower the ultra-deep and ultra-high pressure gas well test tubing in the test fluid. When the ultra-deep and ultra-high pressure gas well test tubing is lowered to near the perforation position, perform depth calibration, short connection matching, set the tubing, hang and remove the blowout preventer, install the gas production wellhead, and test it to pass the pressure test according to the design requirements. Step S2: Pressurize the wellhead according to the design requirements and stabilize it at the rated opening pressure. Transmit the pressure to the downhole safety valve through the hydraulic control pipeline. The downhole safety valve opens, and the gas testing channel of the ultra-deep and ultra-high pressure gas well test string is opened. Step S3: Continuously pressurize the test fluid at the wellhead to the design value, perform tubing transfer perforation operation, perforate the test section, and execute the perforation density, phase angle, and perforation pattern according to the design. Step S4: Perform drainage and testing: Drain fluid according to design requirements or using an oil nozzle; After confirming perforation on site, shut in the well for observation. Once the wellhead pressure stabilizes within the set range, calculate the formation pressure and predict the maximum wellhead shut-in pressure; During the trial production period, the production pressure differential must be controlled to be less than the predicted sand production pressure differential; During the trial production period, accurately record production, pressure, and complete sample analysis data. Step S5: Well shut-in and venting: After the gas test is completed, depressurize the wellhead according to the design requirements, release the pressure in the hydraulic control pipeline, close the downhole safety valve, and then discharge the high-pressure gas from the downhole safety valve to the wellhead through the surface pipeline. Step S6: Killing the well and pulling the tubing string: After the wellhead oil pressure drops to 0, start the pump to kill the well. Based on the formation pressure tested after perforation, select the kill fluid with the set density to kill the well. After killing the well, perform the replacement operation.

4. The testing method for ultra-deep and ultra-high pressure gas wells according to claim 3, characterized in that, In step S1, all tubing entering the well is cleaned using a pipe gauge of the appropriate specification.

5. The testing method for ultra-deep and ultra-high pressure gas wells according to claim 4, characterized in that, In step S1, the speed at which the tubing is lowered is within a set range.

6. The testing method for ultra-deep and ultra-high pressure gas wells according to claim 5, characterized in that, In step S1, before the downhole safety valve is lowered, the hydraulic pipeline of the downhole safety valve is pressure tested. The test pressure value is the rated opening pressure to verify whether the downhole safety valve opens normally. During the downhole safety valve's lowering, the lowering speed is controlled. For each tubing section lowered in the second test tubing, the hydraulic control line is secured to the tubing coupling using a safety valve clamp.

7. The testing method for ultra-deep and ultra-high pressure gas wells according to claim 3, characterized in that, In step S3, the test fluid with the liquid level at the wellhead is continuously pressurized to the design value, which is a negative pressure of 10-15 MPa.

8. The testing method for ultra-deep and ultra-high pressure gas wells according to claim 7, characterized in that, In step S3, the perforation uses a dual detonator. The first part uses a delayed perforation, and the bottom part uses a non-delayed perforation. The upper detonation pressure is lower than the bottom detonation pressure. If the first detonator fails to detonate, the tail detonator is detonated to perform the perforation operation.

9. The testing method for ultra-deep and ultra-high pressure gas wells according to claim 8, characterized in that, In step S3, the bottom detonation pressure is 20 MPa.

10. The testing method for ultra-deep and ultra-high pressure gas wells according to claim 3, characterized in that, In step S4, the well is shut in three times with controlled pressure drainage via surface pipeline, with each drainage consisting of 3-5 cubic meters of fluid. This process is used to determine the properties of the formation fluid and its seepage capacity, providing basic data for subsequent trial production, testing, and formation sealing.

11. The testing method for ultra-deep and ultra-high pressure gas wells according to claim 10, characterized in that, In step S6, firstly, the oil pipe flowing from the surface to the safety valve is filled with kill fluid using a pump truck. Then, the wellhead is pressurized according to the design requirements and stabilized at the rated opening pressure. The pressure is transmitted to the downhole safety valve through the hydraulic control pipeline. The downhole safety valve opens, the oil casing is connected, and the circulating kill operation begins. After the circulating well control is stable until the oil casing pressure drops to 0, the open well observation time should be greater than one wellhead replacement device operation cycle. After confirming that there are no abnormalities, the well should be circulated and washed again for more than 1.5 times the wellbore volume. Only if there are no abnormalities can the replacement operation be carried out.

12. The testing method for ultra-deep and ultra-high pressure gas wells according to claim 3, characterized in that, In step S6, when selecting a kill fluid of a set density for kill, the volume of the kill fluid of the set density is twice the wellbore volume.

13. The testing method for ultra-deep and ultra-high pressure gas wells according to claim 3, characterized in that, In step S6, during the replacement process, the oil / gas tree gate valve is fully opened to keep the liquid level at the wellhead. After removing the wellhead gas tree, installing the blowout preventer, and passing the pressure test according to the design requirements, pull out the perforation test string. Before tripping out of the well, prepare a combination of internal blowout preventers such as plug valves and blowout preventers, and ensure that the outer diameter of the blowout preventer matches the gate size of the blowout preventer. The amount of kill fluid injected should match the amount of tubing removed during the tripping operation. If the amount of kill fluid injected is less than the required amount, the tripping operation should be stopped and the well shut in for observation. If the oil casing pressure does not rise and there is no overflow, the cause should be identified and eliminated before the tubing string can be raised or lowered. Once all tubing has been removed, the oil testing operation is complete.

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