Underground pressure self-adaptive three-parameter probe and using method thereof

Abstract

The invention belongs to the technical field of oil exploration tension well temperature mud resistivity logging, and particularly discloses a downhole pressure self-adaptive three-parameter probe and a using method thereof. Comprising a probe shell, a first through hole is formed in one end of the probe shell along the axis, a pressure-bearing plug is arranged at one end of the first through hole, the other end of the first through hole is connected with a probe upper connector, a balance assembly, a temperature sensor and a resistivity sensor are arranged on the side wall of the probe shell, and a plurality of oil injection holes are further formed in the side wall of the probe shell. An oil injection screw is arranged in each oil injection hole, a second through hole is formed in the probe upper connector along the axis, a limiting stud, a connecting shaft and a tensiometer are sequentially arranged in the second through hole, and a pressure-bearing plug is arranged at the end, away from the probe shell, of the second through hole. According to the invention, the balance assembly and each measurement assembly are detachable, so that the problem that the measurement accuracy is affected due to difficulty in disassembly and maintenance caused by long-term contact between the balance assembly and slurry is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of tension well temperature mud resistivity logging in oil exploration, and particularly relates to a downhole pressure adaptive three-parameter probe and a method for using the same. Background Art

[0002] The tension well temperature mud resistivity logging tool is located at the upper end of the telemetry sub, and mainly measures three parameters: cable head tension, mud resistivity, and borehole temperature. This tool is frequently used in actual logging operations, with a large total number of tools and a large amount of maintenance work. Users' requirements for the reliability of the tool are increasing day by day.

[0003] This three-parameter probe is the core component of the tension well temperature mud resistivity logging tool. Generally, it consists of a probe housing, an upper joint of the probe, a tensiometer, a temperature sensor, a resistivity sensor, and a balancing mechanism, etc., and can measure downhole temperature, mud resistivity, and cable head tension parameters.

[0004] In the existing instrument structure technology of three-parameter logging tools, a hydraulic oil balancing structure is mostly adopted to balance the internal and external pressures of the tool through a rubber bladder or piston structure. Due to the corrosion of hydrogen sulfide and other substances downhole, the rubber bladder has a short service life, needs to be frequently replaced, and has poor reliability. When using a piston balancing structure, parts such as the balancing piston, balancing spring, and mandrel are mostly integrally serially assembled with the tensiometer, temperature sensor, and resistivity sensor. After long-term use, mud accumulates at the balancing piston, causing the piston to jam during movement. This not only fails to achieve the balance protection of the internal and external pressures of the tool, but also interferes with the tension measurement value, resulting in non-linear fluctuations in the measurement value, making the tool unable to provide accurate cable head tension parameters. In addition, due to the integral structure, the disassembly and repair of the balancing piston part are complex, the tool is difficult to maintain, requires frequent maintenance, and has a high cost.

[0005] The existing technologies have the following defects:

[0006] (1) In the existing multiple three-parameter logging tools, the hydraulic balancing mechanism is associated with the tensiometer, temperature sensor, and resistivity sensor in the assembly structure, which is likely to interfere with the detection of tension parameters and results in inaccurate measurement values.

[0007] (2) The original probe assembly structure of the existing three-parameter logging tool is complex and has poor interchangeability. After the balancing piston reciprocates for a long time, mud and water invade. If the mud is not cleaned in time, it will remain and solidify inside the piston structure. The tool requires disassembling many parts, with a large scope involved, and has poor maintainability.

[0008] (3) When the balancing piston is in the extreme state of travel, the internal and external pressure balance fails, especially the problem of the safety of tool use caused by excessive internal pressure. Summary of the Invention

[0009] The object of the present invention is to provide a downhole pressure adaptive three-parameter probe and its usage method, so as to solve the technical problems that each component of the existing three-parameter probe is easily damaged and difficult to disassemble, and the maintainability is poor.

[0010] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0011] In the first aspect, the present invention provides a downhole pressure adaptive three-parameter probe, including a probe housing. One end of the probe housing is axially provided with a first through hole. One end of the first through hole is provided with a first pressure-bearing plug, and the other end of the first through hole is connected to a probe upper joint. A balance assembly, a temperature sensor and a resistivity sensor are provided on the side wall of the probe housing. A plurality of oil injection holes are also provided on the side wall of the probe housing, and the oil injection holes are communicated with the first through hole. An oil injection screw is provided in each oil injection hole. A second through hole is axially provided in the probe upper joint, and a limit stud, a connecting shaft and a tensiometer are sequentially arranged in the second through hole. A second pressure-bearing plug is provided at the end of the second through hole away from the probe housing.

[0012] A further improvement of the present invention is that: the balance assembly is connected to the first through hole through a one-way valve.

[0013] A further improvement of the present invention is that: a safety hole is also provided on the side wall of the probe housing, the safety hole is communicated with the first through hole, and a safety valve is provided in the safety hole.

[0014] A further improvement of the present invention is that: the limit stud is threadedly connected to the second through hole.

[0015] A further improvement of the present invention is that: the probe upper joint and the probe housing are fixedly connected through a plurality of connecting pins.

[0016] A further improvement of the present invention is that: one end of the tensiometer is threadedly connected to the connecting shaft, and the other end of the tensiometer is threadedly connected to the first through hole.

[0017] A further improvement of the present invention is that: the connecting shaft is a conical structure.

[0018] A further improvement of the present invention is that: the balance assembly includes a balance housing. A cavity is provided in the balance housing. One end of the balance housing is provided with a balance cylinder plug, and the other end is provided with a joint. A sealing joint is provided at the outlet of the joint. A balance piston is provided in the cavity. A positive pressure spring and a volume sleeve are sequentially arranged between the joint and the balance piston. An overflow valve spring and an overflow valve needle are provided in the balance piston.

[0019] A further improvement of the present invention is that: a piston seal ring is sleeved outside the balance piston.

[0020] In a second aspect, the present invention provides a method for using a downhole pressure self-adaptive three-parameter probe, comprising the following steps:

[0021] Connect the upper joint of the probe to the logging instrument;

[0022] Fill silicone oil into the first through hole, and adjust the balance assembly so that the pressure in the first through hole is positive;

[0023] Lower it into the well to be measured, and measure through the tensiometer, temperature sensor and resistivity sensor;

[0024] Leave the well to be measured to complete one logging.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] 1. By making the balance assembly and each measurement assembly detachable, the present invention avoids the problem that it is difficult to disassemble and maintain due to the long-term contact of the balance assembly with the mud, thus affecting the measurement accuracy.

[0027] 2. By filling the internal cavity with silicone oil and realizing the self-adaptive adjustment of pressure balance with the outside through the detachable modular balance assembly, the balance piston of which has a safety overflow protection mechanism, which can realize automatic pressure relief protection in the extreme situation of increasing internal pressure, ensure the pressure balance inside and outside the probe and the electrical sensor components are not damaged, and effectively improve the safety of instrument use.

[0028] 3. In the present invention, the balance assembly is a detachable and modular assembly, separated from the tensiometer, avoiding the interference and influence on the tension measurement value, and improving the reliability of the three-parameter probe operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention, and the schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0030] In the drawings:

[0031] Figure 1 is the main view cross-sectional view of a downhole pressure self-adaptive three-parameter probe of the present invention;

[0032] Figure 2 is the 90-degree rotation cross-sectional view of the main view of a downhole pressure self-adaptive three-parameter probe of the present invention;

[0033] Figure 3 is the S-S cross-sectional view of the main view of a downhole pressure self-adaptive three-parameter probe of the present invention;

[0034] Figure 4 is the main cross-sectional view of the balance assembly in a downhole pressure self-adaptive three-parameter probe of the present invention;

[0035] In the figure: pressure-bearing nut 101; first pressure-bearing plug 102; upper joint of the probe 103; limit stud 104; connecting shaft 105; tensiometer 106; probe housing 107; one-way valve 108; oil filling screw 109; balance assembly 110; safety valve 111; temperature sensor 112; resistivity sensor 113; connecting pin 114; first through hole 115; second through hole 116; second pressure-bearing plug 117; joint 201; sealing joint 202; balance housing 203; positive pressure spring 204; volume sleeve 205; overflow valve spring 206; overflow valve needle 207; piston sealing ring 208; balance piston 209; balance cylinder plug 210. Specific implementation mode

[0036] The present invention will be described in detail below with reference to the drawings and in combination with embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0037] The following detailed descriptions are all exemplary descriptions, aiming to provide further detailed descriptions of the present invention. Unless otherwise specified, all technical terms adopted by the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the present invention are only for describing specific implementation modes, and are not intended to limit the exemplary implementation modes according to the present invention.

[0038] Embodiment 1

[0039] A downhole pressure adaptive three-parameter probe, as Figure 1 shown, includes a probe housing 107. One end of the probe housing 107 is provided with a first through hole 115 along the axis. A pressure-bearing nut 101 is arranged outside the first through hole 115, and a first pressure-bearing plug 102 is arranged inside the first through hole 115. A groove is provided at the other end of the probe housing 107, and an upper joint of the probe 103 is arranged in the groove. The upper joint of the probe 103 and the probe housing 107 are fixedly connected by a plurality of connecting pins 114. A plurality of oil filling holes are provided on the side wall of the probe housing 107, and an oil filling screw 109 is arranged in each oil filling hole. The oil filling holes communicate with the first through hole 115. A safety valve 111 is further arranged on the side wall of the probe housing 107. A balance assembly 110, a temperature sensor 112 and a resistivity sensor 113 are further arranged inside the side wall of the probe housing 107. The balance assembly 10 is communicated with the first through hole 115 through a one-way valve 108. Hydraulic insulating silicone oil is injected through the oil filling screw 109, and together with the balance assembly 110, it forms a hydraulic balance system for the internal and external working conditions of the probe, so as to ensure that the non-pressure-resistant temperature sensor 112 and resistivity sensor 113 can work normally in the downhole high-pressure environment.

[0040] Specifically, a sealing ring is sleeved outside the oil filling screw (109) to achieve a sealing effect.

[0041] A first through hole 116 is provided along the axis inside the upper connector 103 of the probe. At one end of the first through hole 116 far from the probe housing 107, there is a pressure-bearing nut 101 and a second pressure-bearing plug 117. A limit stud 104, a connecting shaft 105 and a tensiometer 106 are arranged in the first through hole 116. The connecting shaft 105 is axially limited and fixed in the first through hole 116 by the limit stud 104. One end of the tensiometer 106 is threadedly connected to the connecting shaft 105, and the other end of the tensiometer 106 is threadedly connected to the first through hole 115. The connecting shaft 105 has a large and small diameter conical structure. The limit stud 104 is threadedly connected to the first through hole 116, and the connecting shaft 105 is locked in the first through hole 116 by the limit stud 104. While ensuring the connection between the upper connector 103 of the probe and the probe housing 107, the detection of the numerical values of the bidirectional stresses of axial tension and compression of the tensiometer 106 is realized.

[0042] Specifically, the temperature sensor 112 and the resistivity sensor 113 can be assembled and disassembled separately as independent module parts.

[0043] Specifically, the balance assembly 110 is also an independent module. The balance assembly 110 is as Figure 4 shown, including a joint 201, a sealing joint 202, a balance housing 203, a positive pressure spring 204, a volume sleeve 205, an overflow valve spring 206, an overflow valve needle 207, a piston sealing ring 208, a balance piston 209, and a balance cylinder plug 210. Combined with the probe housing 107 through a one-way valve 108, the balance assembly 110 forms a sealed cavity through the joint 201, the sealing joint 202, the balance housing 203, the balance piston 209 and corresponding seals, and is filled with insulating oil inside. The balance piston 209 can ensure the internal and external pressure balance. At the same time, due to the stretching of the positive pressure spring 204, the internal maintains a moderate positive pressure higher than the external, so as to actively prevent the intrusion of external mud and water pollutants and effectively improve the reliability of the probe use.

[0044] The volume sleeve 205 is used to reduce the oil filling amount in the internal cavity and also limits the inward movement space of the balance piston 209. In the case of a reduction in the internal silicone oil, it can protect the positive pressure spring 204 and the balance piston 209 from being crushed and damaged. When the internal pressure is lower than the limit state, the safety valve 111 will be triggered and conduct the internal and external spaces to make the internal and external pressures consistent to protect the safety of the internal components of the probe.

[0045] In addition, a safety overflow valve structure composed of an overflow valve spring 206, an overflow valve plunger 207 and corresponding sealing rings is specially designed at the center of the balance piston 209. When the external pressure decreases and the internal silicone oil expands due to a rise in temperature and excessive internal pressure, the volume of the silicone oil expands, pushing the balance piston 209 to move to the left end to the limit. The balance cylinder plug 210 will trigger and push the overflow valve plunger 207, compressing the overflow valve spring 206 to open the safety overflow valve, discharging the pressure and releasing the internal silicone oil, adapting to the pressure fluctuations in the downhole working conditions and ensuring the safety of the internal sensors and electrical circuits.

[0046] While the balance assembly 110 provides protection for the internal and external pressure balance of the three-parameter probe, the one-way valve 108 on the probe housing 107 ensures its independent disassembly. After disassembly, it does not affect the formation of a hydraulic sealed cavity body inside the upper joint 103 and the probe housing 107 of the three-parameter probe. The internally welded electrical connection wires also do not need to be disassembled, and the internal silicone oil cannot leak, effectively improving the convenience of maintaining the three-parameter probe.

[0047] Embodiment 2

[0048] A method for using a downhole pressure self-adaptive three-parameter probe includes the following steps:

[0049] After connecting the upper joint 103 of the probe to the upper adapter of the instrument and the electronic instrument part, a complete tensiometer, well temperature and mud resistivity logging tool is formed. This component can be independently assembled and filled with oil in a cycle for pre-logging preparation. When filling with oil, the positive pressure spring 204 stretches. By checking and calibrating the position dimension of the balance piston 209 in the balance housing 203, an appropriate positive pressure (about 2KG) inside the probe can be preset to actively prevent the intrusion of external mud water pollution. During the logging process, as the external mud pressure in the well increases, the oil pressure of the internal insulating silicone oil in the probe is transmitted through the balance piston to maintain the internal and external pressure balance. Since the internal silicone oil inevitably contains a small amount of gas, the volume of the internal silicone oil is compressed, and the balance piston will move inward slightly from the calibrated position. After the logging task is completed, the instrument is lifted to the ground. Due to the factors of increased internal pressure and expanded volume of the internal silicone oil in the three-parameter probe caused by the rise in downhole temperature and the decrease in external pressure, the balance piston will move outward (to the low-pressure area) by a certain displacement from the calibrated position. Usually within the self-adaptive adjustment range, the balance assembly 110 does not require maintenance. After each logging, only clean it and check whether the position dimension of the balance piston 209 in the balance housing 203 is at the calibrated position when the temperature reaches room temperature.

[0050] In extreme cases, due to the high downhole temperature and the decrease in external pressure, the internal pressure of the silicone oil inside the three-parameter probe increases after logging. The volume expansion pushes the balance piston 209 to move to the extreme position and contact the balance cylinder plug 210, triggering the overflow valve needle 207 and compressing the overflow valve spring 206 to open the safety overflow valve, discharging the pressure and releasing the internal silicone oil. After the probe is cleaned and the temperature reaches room temperature, check that the position dimension of the balance piston 209 in the balance housing 203 is far lower than the calibrated position. Refill the three-parameter probe with silicone oil to make the balance piston 209 reach the calibrated position, thus realizing less maintenance or maintenance-free of the instrument.

[0051] During long-term use (logging 20 times), the balance assembly 110, tensiometer 106, temperature sensor 112, and resistivity sensor 113 can be disassembled for regular maintenance.

[0052] As is known by common technical knowledge, the present invention can be implemented by other embodiments without departing from its spiritual essence or essential features. Therefore, the above-disclosed embodiments are illustrative in all aspects and not exclusive. All changes within the scope of the present invention or equivalent to the present invention are encompassed by the present invention.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that the specific implementation manners of the present invention can still be modified or equivalently replaced. Any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. An underground pressure adaptive three-parameter probe, characterized in that It includes a probe housing (107). One end of the probe housing (107) is axially provided with a first through hole (115). One end of the first through hole (115) is provided with a first pressure-bearing plug (102), and the other end of the first through hole (115) is connected to a probe upper joint (103). A balance assembly (110), a temperature sensor (112), and a resistivity sensor (113) are provided on the side wall of the probe housing (107). A number of oil injection holes are also provided on the side wall of the probe housing (107), and the oil injection holes are communicated with the first through hole. An oil injection screw (109) is provided in each oil injection hole. A second through hole (116) is axially provided in the probe upper joint (103), and a limit stud (104), a connecting shaft (105), and a tensiometer (106) are sequentially provided in the second through hole. A second pressure-bearing plug (117) is provided at the end of the second through hole far from the probe housing (107).

2. The underground pressure adaptive three-parameter probe according to claim 1, characterized in that The balance assembly (110) is connected to the first through hole (115) through a one-way valve (108).

3. The underground pressure adaptive three-parameter probe according to claim 1, characterized in that A safety hole is also provided on the side wall of the probe housing (107), the safety hole is communicated with the first through hole (115), and a safety valve (111) is provided in the safety hole.

4. The underground pressure adaptive three-parameter probe according to claim 1, characterized in that The limit stud (104) is threadedly connected to the second through hole (116).

5. The underground pressure adaptive three-parameter probe according to claim 1, characterized in that The probe upper joint (103) and the probe housing (107) are fixedly connected through a number of connecting pins (114).

6. The underground pressure adaptive three-parameter probe according to claim 1, characterized in that One end of the tensiometer (106) is threadedly connected to the connecting shaft (105), and the other end of the tensiometer (106) is threadedly connected to the first through hole (115).

7. The underground pressure adaptive three-parameter probe according to claim 1, characterized in that The connecting shaft (105) is a conical structure.

8. The underground pressure adaptive three-parameter probe according to claim 1, characterized in that The balance assembly (110) includes a balance housing (203). A cavity is provided in the balance housing (203). One end of the balance housing (203) is provided with a balance cylinder plug (210), and the other end is provided with a joint (201). A sealing joint (202) is provided at the outlet of the joint (201). A balance piston (209) is provided in the cavity. A positive pressure spring (204) and a volume sleeve (205) are sequentially provided between the joint (201) and the balance piston (209). An overflow valve spring (206) and an overflow valve needle (207) are provided in the balance piston (209).

9. The underground pressure adaptive three-parameter probe according to claim 8, characterized in that A piston sealing ring (208) is sleeved outside the balance piston (209).

10. A method for using an underground pressure adaptive three-parameter probe, based on the underground pressure adaptive three-parameter probe according to any one of claims 1 to 9, comprising the following steps: Connect the probe upper joint (103) to the logging instrument; Fill silicone oil into the first through hole (115), and adjust the balance assembly (110) to make the inside of the first through hole (115) a positive pressure; Lower it into the well to be measured, and measure through the tensiometer (106), the temperature sensor (112), and the resistivity sensor (113); Leave the well to be measured to complete one logging.

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