A highly integrated electro-hydraulic separation small-diameter pressure measuring nipple for downhole formation testing

Abstract

The present invention discloses a highly integrated electro-hydraulic separation type small-diameter pressure measuring nipple for downhole formation testing. It includes a liquid-driven nipple, an isolation nipple and an electric-driven pre-test chamber; the liquid-driven nipple is mainly responsible for tightening the well wall to ensure that the small-diameter pressure measuring nipple is fixed at the point to be tested. The isolation nipple mainly provides two formation fluid flow channels, which lead to the electric-driven pre-test chamber and the pumping nipple respectively. The electric-driven pre-test chamber creates conditions for measuring formation pressure by adjusting the size of its internal cavity. The present invention arranges hydraulics and electricity separately to avoid the situation where the hydraulic flow channel needs to run through the entire set of small-diameter pressure measuring nipple, which is conducive to improving the system integration and modularization. The present invention integrates the isolation valve and the diversion flow channel of the formation fluid in the isolation nipple, which not only realizes the interference-free working state switching between pumping and pre-testing, but also effectively shortens the flow channel length between the probe and the quartz pressure gauge, thereby improving the formation pressure measurement accuracy.

Description

Technical Field

[0001] The invention belongs to the field of downhole formation testing equipment, and in particular relates to a highly integrated electric-hydraulic separation type small-diameter pressure measuring nipple for downhole formation testing. Background Art

[0002] In the process of exploration and development of complex oil and gas reservoirs, the formation dynamic tester is currently the most widely used logging instrument. It is mainly responsible for formation pressure measurement and formation fluid sampling. It is a key equipment for upgrading formation evaluation to reservoir evaluation. The formation pressure measurement is completed by the probe short section, and the fluid sampling is completed by the pumping short section. The two short sections are connected by threads. Among them, the formation tester can only suck the formation fluid from the wellbore through the probe short section, and then transfer the formation fluid to the pumping short section through the internal connecting flow channel. The internal connecting flow channel between the two short sections is isolated by the isolation valve in the probe short section. The probe short section consists of a support arm, a probe, a pre-test chamber, an isolation valve and a quartz pressure gauge. First, the support arm and the probe extend from the probe short section to fix the formation tester at the point to be tested. Then the isolation valve isolates the connecting flow channel between the short sections to form a local flow channel from the probe to the pre-test chamber, and the formation fluid pressure changes by adjusting the size of the cavity in the pre-test chamber. After the pre-test is completed, the isolation valve is opened and the formation fluid flows directly into the pumping nipple for fluid sampling. During the above operation, the changes in the formation fluid properties are recorded by the quartz pressure gauge and transmitted to the ground assembly workstation. The actions of all components depend on the electro-hydraulic system and are controlled by switching the solenoid valve group.

[0003] As exploration tasks move toward ultra-deep wells, formation testers are gradually developing in the direction of small-diameter integration. The existing formation tester probe pup section arranges the isolation valve and pre-test chamber on the left side of the probe, resulting in the formation fluid sucked from the probe flowing to the left first, passing through the isolation valve and pre-test chamber, and then flowing to the right into the pumping pup section. This U-shaped flow channel layout will cause the internal flow channel to be too long, resulting in a large pressure loss along the way, which is not conducive to accurate measurement of formation pressure and rapid fluid sampling. At the same time, the current formation tester pre-test chamber uses a hydraulic system as a power source, which makes it difficult to accurately control the change in pre-test volume, and is not suitable for pressure measurement in low permeability formations. In addition, the existing electrical, hydraulic and formation fluid flow channels all adopt a straight-line penetration method, which is not only difficult to process, but also not conducive to the integrated layout of components. Summary of the invention

[0004] The highly integrated electro-hydraulic separation small-diameter pressure measuring nipple for downhole formation testing proposed by the present invention can solve the above mentioned contradiction. The present invention can be understood as a design scheme for improving the integration of the probe nipple.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a highly integrated electro-hydraulic separation type small-diameter pressure measuring nipple for downhole formation testing, which comprises a liquid drive nipple, an isolation nipple and an electric drive pre-test chamber; the liquid drive nipple, the isolation nipple and the electric drive pre-test chamber are sequentially connected in series into one body, and are connected and fixed to each other by threaded welding sleeves;

[0007] The liquid-driven short joint is used to hold up the well wall to ensure that the small-diameter pressure-measuring short joint is fixed at the point to be tested. It includes a liquid-driven short joint body and an electromagnetic valve group, a balancing valve, a probe and a support arm mounted on the liquid-driven short joint body; wherein the liquid-driven short joint body contains a hydraulic flow channel and a formation fluid flow channel; the electromagnetic valve group is arranged on the hydraulic flow channel to control the action of the balancing valve, the probe and the support arm by controlling the on-off of the hydraulic flow channel, and the balancing valve and the probe both provide the small-diameter pressure-measuring short joint with a formation fluid flow port that can intersect with the wellbore formation fluid, wherein the balancing valve can block its formation fluid flow port when extended; the probe and the support arm are responsible for fixing the small-diameter pressure-measuring short joint at the point to be tested;

[0008] The isolation nipple comprises an isolation nipple body and a quartz pressure gauge, a resistivity sensor, and an isolation valve arranged in the isolation nipple body; the isolation nipple provides two formation fluid flow paths, one end of the two formation fluid flow paths intersect at the inlet of the resistivity sensor, and are connected with the formation fluid flow path of the liquid drive nipple after passing through the quartz pressure gauge, the other end of the first formation fluid flow path directly leads to the electric drive pre-test chamber, and the other end of the second formation fluid flow path passes through the resistivity sensor and the isolation valve and then leads to the electric drive pre-test chamber;

[0009] The electric drive pre-test chamber includes a short section housing, a pre-test chamber and an additional flow channel located in the short section housing; the pre-test chamber includes a motor, a reducer, a pre-test chamber piston and a pre-test chamber housing; the first formation fluid flow channel of the isolation short section leads to a local cavity formed between the pre-test chamber piston and the pre-test chamber housing, and the second formation fluid flow channel of the isolation short section flows to the additional flow channel and finally flows into the pumping short section.

[0010] As a preferred embodiment of the present invention, the balancing valve is closed during pre-testing and pumping, closing the formation fluid flow port to prevent the inflow of downhole formation fluid and thus affecting the pressure measurement and sampling stability; the balancing valve is opened in other stages, allowing the wellbore formation fluid to flow into the internal formation fluid flow channel of the small diameter pressure measuring nipple to balance the internal and external pressures, and prevent the surface of the small diameter pressure measuring nipple from being crushed due to excessive pressure difference.

[0011] As a preferred embodiment of the present invention, when the isolation valve is in a closed state, the second formation fluid flow channel of the isolation short section is blocked, and the pre-test working mode is entered; when the isolation valve is in an open state, the second formation fluid flow channel of the isolation short section is opened, and the pumping working mode is entered.

[0012] The hydraulic flow channel in the liquid drive pup joint can be regarded as a pipeline for circulating hydraulic oil, and the formation fluid flow channel can be regarded as a pipeline for circulating formation fluid in the well. The formation fluid flow channel mainly functions to circulate formation fluid in the well. The hydraulic oil in the hydraulic flow channel of the liquid drive pup joint is provided by the upper-level pup joint of the small-diameter pressure measuring pup joint in the present invention, and will not affect the specific implementation method of the present invention. Similarly, the pumping pup joint is the latter-level pup joint of the small-diameter pressure measuring pup joint. The specific implementation method of the present invention only needs to provide a formation fluid flow channel for the pumping pup joint to introduce the formation fluid in the wellbore into the pumping pup joint. The working principle and structural layout of the pumping pup joint will not affect the specific implementation method of the present invention.

[0013] As a preferred solution of the present invention, no hydraulic flow channel is arranged in the isolation pup joint and the electric drive pre-test chamber.

[0014] As a preferred embodiment of the present invention, the solenoid valve group controls the flow of hydraulic oil in the hydraulic channel by controlling the opening and closing of the valve port; the balancing valve, probe and support arm are all actuators that can perform telescopic movements under the control of the solenoid valve group.

[0015] As a preferred solution of the present invention, a quartz pressure gauge is further provided in the isolation pup joint; the pressure measuring terminal of the quartz pressure gauge is connected to the formation fluid flow channel in the isolation pup joint to monitor the formation fluid pressure change.

[0016] As a preferred embodiment of the present invention, the motor and the reducer are connected via a coupling; the reducer and the pre-test chamber piston are connected via threads; the motor, the reducer and the pre-test chamber piston are connected in series in sequence and then installed inside the pre-test chamber housing to form a completed pre-test chamber.

[0017] Compared with the prior art, the present invention reduces the complexity of the electro-hydraulic system in the liquid-driven short section through the electric drive design of the isolation valve and the pre-test chamber, alleviates the inherent defects of the hydraulic system introduced by high temperature, and arranges the hydraulic and electrical separately, avoiding the situation where the hydraulic flow channel needs to run through the entire set of small-diameter pressure measuring short sections, which is conducive to improving the system integration and modularization. The present invention integrates the isolation valve and the formation fluid diversion flow channel in the isolation short section, which not only realizes the interference-free working state switching between pumping and pre-testing, but also effectively shortens the formation fluid flow channel length between the probe and the quartz pressure gauge, improves the formation pressure measurement accuracy, and avoids the problem of large pressure loss along the way caused by the U-shaped arrangement of the formation fluid flow channel in the traditional scheme. In addition, the present invention adopts an internal flow channel layout scheme with the shortest distance as the primary principle, improves the internal space utilization of the small-diameter pressure measuring short section, and further improves the system integration. In summary, the highly integrated electro-hydraulic separation type small-diameter pressure measuring short section for downhole formation testing proposed by the present invention provides great help for the exploration and development of oil and gas reservoirs in narrow spaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is an overall schematic diagram of a highly integrated electro-hydraulic separation small-diameter pressure measuring nipple for downhole formation testing;

[0019] Figure 2 and Figure 7 This is a schematic diagram of the liquid drive short section structure;

[0020] Figure 3 This is a schematic diagram of the isolation short section structure;

[0021] Figure 4 This is a schematic diagram of the structure of the electric drive pre-test room;

[0022] Figure 5 This is a schematic diagram of the pre-test room structure;

[0023] Figure 6 This is a schematic diagram of the liquid drive short section in working condition.

[0024] In the figure, 1-liquid drive short section; 2-isolation short section; 3-electric drive pre-test chamber; 4-threaded welding sleeve; 101-solenoid valve group; 102-balance valve; 103-probe; 104-support arm; 105-liquid drive short section body; 201-quartz pressure gauge; 202-resistivity sensor; 203-isolation valve; 204-isolation short section body; 301-pre-test chamber; 302-short section shell; 303-additional flow channel; 3011-motor; 3012-reducer; 3013-pre-test chamber piston; 3014-pre-test chamber shell. DETAILED DESCRIPTION

[0025] The present invention is further described and illustrated below in conjunction with specific embodiments. The embodiments are merely exemplary of the present disclosure and do not define the scope of limitation. The technical features of each embodiment of the present invention may be combined accordingly without conflicting with each other.

[0026] The overall diagram of the highly integrated electro-hydraulic separation small-diameter pressure measuring nipple designed by the present invention for downhole formation testing is as follows: Figure 1 As shown, it is mainly composed of a liquid drive short section 1, an isolation short section 2 and an electric drive pre-test chamber 3. Among them, the liquid drive short section 1 is mainly responsible for tightening the well wall to ensure that the small diameter pressure measuring short section is fixed at the test point. The isolation short section 2 mainly provides two formation fluid flow channels, which lead to the electric drive pre-test chamber 3 and the pumping short section respectively. The electric drive pre-test chamber 3 creates conditions for measuring formation pressure by adjusting the size of its internal cavity. The liquid drive short section 1, the isolation short section 2 and the electric drive pre-test chamber 3 are connected in series in sequence, and are connected and fixed to each other by a threaded welding sleeve 4.

[0027] The electric drive pre-test chamber 3 uses a motor direct drive method to measure the formation permeability, which improves the formation pressure measurement accuracy. The present invention performs an electric-liquid separation design and an internal flow channel optimization layout design in terms of layout, which reduces the difficulty of processing and assembly and greatly improves the integration of small-diameter pressure measuring nipples.

[0028] like Figure 2 , Figure 6 and Figure 7 As shown, the liquid drive short section 1 is composed of a solenoid valve group 101, a balance valve 102, a probe 103, a support arm 104, and a liquid drive short section body 105. The solenoid valve group 101 is mainly responsible for controlling the on and off of the oil circuit to control the movement of the balance valve 102, the probe 103 and the support arm 104. The liquid drive short section body 105 is mainly responsible for carrying various components, and contains hydraulic flow channels and formation fluid flow channels inside. The balance valve 102 and the probe 103 both provide a formation fluid flow port for the small diameter pressure measuring short section that can intersect with the wellbore formation fluid. Among them, the formation fluid flow channel of the liquid drive short section 1 connects the two formation fluid flow ports and finally extends to the right side of the liquid drive short section 1. The balance valve 102 is closed during pre-testing and pumping, and the formation fluid flow port is closed to prevent the downhole formation fluid from flowing into the short section and thus affecting the stability of pressure measurement and sampling. The balance valve 102 is open in all other stages, allowing the wellbore formation fluid to flow into the formation fluid flow channel inside the small diameter pressure measuring nipple to balance the internal and external pressures, and prevent the surface of the pressure measuring nipple from being crushed due to excessive pressure difference. The probe 103 and the support arm 104 are jointly responsible for fixing the small diameter pressure measuring nipple at the point to be tested.

[0029] like Figure 3 As shown, the isolation pup joint 2 is composed of a quartz pressure gauge 201, a resistivity sensor 202, an isolation valve 203 and an isolation pup joint body 204. The formation fluid flow channel inside the isolation pup joint 2 is split at the resistivity sensor 202, that is, one formation fluid flow channel is arranged on the left side of the resistivity sensor 202, and two formation fluid flow channels are arranged on the right side. The formation fluid flow channel on the left side passes through the quartz pressure gauge 201 to record the formation fluid pressure change process in the formation fluid flow channel. The first formation fluid flow channel on the right side directly leads to the electric drive pre-test chamber 3, and the second formation fluid flow channel passes through the resistivity sensor 202 and the isolation valve 203 and then leads to the electric drive pre-test chamber 3. The threaded welding sleeve 4 connects the formation fluid flow channel on the left side of the isolation pup joint 2 with the formation fluid flow channel of the liquid drive pup joint 1. The isolation valve 203 and the motor are integrated into a design, which greatly reduces the space occupied volume.

[0030] like Figure 4 and Figure 5As shown, the electric drive pre-test chamber 3 is composed of a pre-test chamber 301, a short section housing 302 and an additional flow channel 303. The pre-test chamber 301 is composed of a motor 3011, a reducer 3012, a pre-test chamber piston 3013 and a pre-test chamber housing 3014. The motor 3011 is connected to the reducer 3012 through a coupling, and the reducer 3012 is connected to the pre-test chamber piston 3013 through a threaded connection. After the motor 3011, the reducer 3012 and the pre-test chamber piston 3013 are connected in series in sequence, they are installed in the pre-test chamber housing 3014. The electric drive pre-test chamber 3 is connected to the isolation short section 2 through a threaded welding sleeve 4. The electric drive pre-test chamber 3 contains two formation fluid flow channels, the first formation fluid flow channel is passed into the local cavity formed between the pre-test chamber piston 3013 and the pre-test chamber housing 3014, and the second formation fluid flow channel flows to the additional flow channel 303 and finally flows into the pumping short section. The threaded welding sleeve 4 connects the formation fluid flow channel inside the electric drive pre-test chamber 3 to the formation fluid flow channel in the isolation short section 2. When the isolation valve 203 is in the closed state, the second formation fluid flow channel of the isolation short section 2 is blocked, and the pre-test working mode is entered. When the isolation valve 203 is in the open state, the second formation fluid flow channel of the isolation short section 2 is opened, and the pumping working mode is entered, realizing the interference-free working state switching between pumping and pre-testing. There is no need to arrange hydraulic flow channels in the isolation short section 2 and the electric drive pre-test chamber 3, and only electrical components are assembled, avoiding the through-type design of the hydraulic flow channel in the traditional scheme and realizing the electro-hydraulic separation arrangement.

[0031] The highly integrated electro-hydraulic separation type small-diameter pressure measuring nipple for downhole formation testing proposed in the present invention focuses on improving the system integration, which is mainly achieved by pre-test electric drive, non-interference flow channel diversion, electro-hydraulic separation layout and internal flow channel optimization layout. The present invention brings the following basic advantages: First, the pre-test chamber piston is directly driven by a motor, which improves the suction accuracy and response speed compared with traditional hydraulic control; second, the formation fluid flow channel is diverted by an electric drive isolation valve to achieve non-interference working state switching between pumping and pre-testing; third, the structure of the traditional probe nipple is rearranged, divided into three modules: liquid drive nipple, isolation nipple and electric drive pre-test chamber (the liquid drive nipple is controlled by hydraulic pressure, and the isolation nipple and electric drive pre-test chamber are controlled by motor), realizing the electro-hydraulic separation layout, which is conducive to improving the integration and modularization of the small diameter pressure measuring nipple; fourth, the internal flow channel is optimized based on metal additive manufacturing technology, following the principle of the shortest flow channel, improving the internal space utilization of the small diameter pressure measuring nipple, and realizing the high integration design of the system.

[0032] In view of the problems of low integration of the existing formation tester probe pup section, high spatial layout coupling, poor pressure measurement adaptability, etc., the present invention designs the isolation valve and the pre-test chamber to be electrically driven, and separates the hydraulic and electrical layouts to avoid the through-type hydraulic flow channel in the traditional probe pup section, effectively improving the problems of low pressure measurement accuracy and slow response caused by the excessively long formation fluid flow channel, improving the integration and modularity of small-diameter pressure measurement pup sections, and facilitating system assembly and later fault diagnosis and positioning. In addition, the internal flow channel is optimized based on metal additive manufacturing technology, which reduces the difficulty of machining and assembling the probe pup section and greatly improves the integration of the pressure measurement pup section. In summary, the present invention has great application potential in realizing highly integrated probe pup sections for small-diameter formation dynamic testers.

[0033] During operation, when the small-diameter pressure measuring sub is lowered from the ground to the test point, the balance valve 102 and the isolation valve 203 are always in the open state, ensuring that the pressure of the formation fluid flow channel inside the small-diameter pressure measuring sub is equal to the formation pressure downhole. After reaching the test point, the probe 103 and the support arm 104 are extended and tightly pressed against the well wall under the control of the electromagnetic valve group 101, fixing the small-diameter pressure measuring sub at the test point. The isolation valve 203 is switched to the closed state, and the formation fluid flow channel leading to the pumping sub is cut off. At the same time, the balance valve 102 is closed, and the small-diameter pressure measuring sub has only one formation fluid flow port, the probe 103, which can be connected to the external formation fluid. At this time, a local formation fluid flow channel from the probe 103 to the isolation sub 2 to the pre-test chamber piston 3013 is formed inside the small-diameter pressure measuring sub. The pre-test chamber piston 3013 gradually contracts under the control of the motor 3011, causing the formation fluid pressure in the local fluid flow channel to drop. At this time, due to the imbalance of internal and external pressures, the formation fluid in the wellbore flows in through the probe 103 to compensate for the pressure loss. In the above process, the formation pressure of the local formation fluid flow channel will first drop and then slowly recover. The pressure change process is recorded by the quartz pressure gauge 201 and the resistivity sensor 202, and uploaded to the ground assembly workstation for analysis to determine the phase state and flow properties of the oil and gas reservoir fluid. In the traditional formation tester structure scheme, the isolation valve and the pre-test chamber are both located on the left side of the probe, resulting in the fluid flow channel having to be arranged in a U shape before it can flow into the subsequent pumping short section. The present invention proposes to arrange the isolation valve 203 on the right side of the probe 103, so that the formation fluid can directly enter the pumping short section quickly after passing through the isolation valve 203 to the right, greatly shortening the length of the formation fluid flow channel and reducing the pressure loss of the formation fluid along the way. After completing the pre-test, the isolation valve 203 is opened, and the formation fluid flow channel from the probe 103 to the pumping short section is opened, realizing the interference-free switching between pre-testing and pumping.

[0034] In addition, since the traditional flow channel layout is designed for convenient machining, it is not conducive to the high integration of the formation tester, and the pressure loss along the way is obvious. In view of the above shortcomings, the present invention uses metal additive manufacturing technology to optimize the layout of the formation fluid flow channel and the hydraulic flow channel based on the principle of shortest distance, such as Figure 2-4 The flow channel shown. The present invention integrates the isolation valve and the formation fluid diversion flow channel in the isolation short section to achieve the interference-free switching of the working state of pumping and pre-testing; the present invention electrically drives the isolation valve and the pre-test chamber to effectively reduce the complexity of the electro-hydraulic system and alleviate the inherent defects of the hydraulic system caused by the high-temperature downhole environment; the present invention arranges the hydraulic components and the electrical components separately, avoiding the need for a through-type hydraulic flow channel in the traditional probe short section, which is conducive to improving the system integration and modularization, and lays a good foundation for the later system assembly and fault troubleshooting and positioning; the present invention designs the flow channel layout with the shortest distance as the goal, and improves the system integration of the small-diameter pressure measuring short section.

[0035] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. For ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A highly integrated electro-hydraulic separation small-diameter pressure measuring nipple for downhole formation testing, characterized in that It comprises a liquid drive short section (1), an isolation short section (2) and an electric drive pre-test chamber (3); the liquid drive short section, the isolation short section and the electric drive pre-test chamber are sequentially connected in series into one body and are connected and fixed to each other via a threaded welding sleeve; The liquid drive short joint (1) is used to support the well wall and ensure that the small diameter pressure measuring short joint is fixed at the point to be tested. It includes a liquid drive short joint body (105) and an electromagnetic valve group (101), a balance valve (102), a probe (103) and a support arm (104) mounted on the liquid drive short joint body (105); wherein the liquid drive short joint body (105) contains a hydraulic flow channel and a formation fluid flow channel; the electromagnetic valve group (101) is arranged on the hydraulic flow channel to control the action of the balance valve (102), the probe (103) and the support arm (104) by controlling the on and off of the hydraulic flow channel; the balance valve (102) and the probe (103) both provide the small diameter pressure measuring short joint with a formation fluid flow port that can intersect with the wellbore formation fluid, wherein the balance valve (102) can block its formation fluid flow port when extended; the probe (103) and the support arm (104) are responsible for fixing the small diameter pressure measuring short joint at the point to be tested; The isolation sub (2) comprises an isolation sub body (204) and a quartz pressure gauge (201), a resistivity sensor (202), and an isolation valve (203) arranged in the isolation sub body (204); the isolation sub (2) provides two formation fluid flow paths, one end of the two formation fluid flow paths intersects at the entrance of the resistivity sensor (202), and is connected to the formation fluid flow path of the liquid drive sub (1) after passing through the quartz pressure gauge (201); the other end of the first formation fluid flow path directly leads to the electric drive pre-test chamber (3), and the other end of the second formation fluid flow path passes through the resistivity sensor (202) and the isolation valve (203) and then leads to the electric drive pre-test chamber (3); The electric drive pre-test chamber (3) comprises a short section housing (302), a pre-test chamber (301) and an additional flow channel (303) located in the short section housing (302); the pre-test chamber (301) comprises a motor (3011), a reducer (3012), a pre-test chamber piston (3013) and a pre-test chamber housing (3014); a first formation fluid flow channel of the isolation short section leads into a local cavity formed between the pre-test chamber piston (3013) and the pre-test chamber housing (3014), and a second formation fluid flow channel of the isolation short section flows to the additional flow channel (303) and finally flows into the pumping short section.

2. The highly integrated electro-hydraulic separation small-diameter pressure measuring nipple for downhole formation testing according to claim 1, characterized in that: The balancing valve (102) is closed during pre-testing and pumping, closing the formation fluid flow port to prevent the inflow of downhole formation fluid and thus affecting the pressure measurement and sampling stability; the balancing valve (102) is opened in other stages, allowing the wellbore formation fluid to flow into the internal formation fluid flow channel of the small diameter pressure measuring nipple to balance the internal and external pressures, and preventing the surface of the small diameter pressure measuring nipple from being crushed due to excessive pressure difference.

3. The highly integrated electro-hydraulic separation type small-diameter pressure measuring nipple for downhole formation testing according to claim 1, characterized in that: When the isolation valve (203) is in a closed state, the second formation fluid flow channel of the isolation short section (2) is blocked, and the pre-test working mode is entered at this time; when the isolation valve (203) is in an open state, the second formation fluid flow channel of the isolation short section (2) is opened, and the pumping working mode is entered at this time.

4. The highly integrated electro-hydraulic separation type small-diameter pressure measuring nipple for downhole formation testing according to claim 1, characterized in that: No hydraulic flow channel is arranged in the isolation short section (2) and the electric drive pre-test chamber (3).

5. The highly integrated electro-hydraulic separation type small-diameter pressure measuring nipple for downhole formation testing according to claim 1, characterized in that: The solenoid valve group (101) controls the flow of hydraulic oil in the hydraulic channel by controlling the opening and closing of the valve port; the balance valve (102), the probe (103) and the support arm (104) are all actuators that can perform telescopic movements under the control of the solenoid valve group (101).

6. The highly integrated electro-hydraulic separation type small diameter pressure measuring nipple for downhole formation testing according to claim 1, characterized in that: A quartz pressure gauge (201) is also provided in the isolation short joint (2); the pressure measuring terminal of the quartz pressure gauge is connected to the formation fluid flow channel in the isolation short joint to monitor the change of formation fluid pressure.

7. The highly integrated electro-hydraulic separation type small diameter pressure measuring nipple for downhole formation testing according to claim 1, characterized in that: The motor (3011) and the reducer (3012) are connected via a coupling; the reducer (3012) and the pre-test chamber piston (3013) are connected via threads; the motor (3011), the reducer (3012) and the pre-test chamber piston (3013) are sequentially connected in series and then installed inside the pre-test chamber housing (3014) to form a completed pre-test chamber (301).

Images