A test system and method for gas extraction amount of each fracture section of a segmented fracturing long borehole

Abstract

The application discloses a kind of segmented fracturing long borehole each fractured section gas extraction quantity test system and method, including data acquisition system and sequentially connected water tank, high-pressure pump and mining continuous tube car, the mining continuous tube car includes bottom plate, the bottom of the bottom plate is provided with a pair of track, the lateral front side of the top of the bottom plate is provided with support rod, the support rod is provided with rotating shaft, the rotating shaft is rotatably provided with drum;The application is by being arranged in continuous tube distribution type pressure, temperature test optical fiber, using water tank, high-pressure pump and mining continuous tube car will continuous tube push into directional long borehole wellbore, using data acquisition system real-time measurement each fractured section pressure data and temperature data, and test process does not interfere with long borehole normal gas extraction, solve the technical problems that gas extraction equipment in the prior art cannot realize the independent measurement and evaluation of coal mine underground directional long borehole single fractured section gas extraction quantity.

Description

Technical Field

[0001] This invention belongs to the field of coal mine gas extraction technology, and relates to a gas extraction volume testing system, specifically a testing system and method for the gas extraction volume of each fracturing section in a segmented fracturing long borehole. Background Technology

[0002] Coal seams in my country generally have low permeability, making gas drainage difficult. To improve gas drainage efficiency, directional long-bore fracturing technology has been introduced into underground coal mines. On the one hand, relying on the rapidly developing drilling capabilities in underground coal mines, the drilling depth is increased, and the contact area between the borehole and the formation is improved. On the other hand, after casing is installed, long boreholes are fracturing in stages, forming a large-scale fracture network in the coal seam or surrounding rock, providing a rapid channel for gas seepage into the wellbore. After directional long-bore fracturing, the gas is connected to the underground gas drainage pipeline for negative pressure gas drainage. At this time, only a flow meter can be installed at the borehole opening to obtain the total gas drainage data, but it is impossible to obtain the gas drainage volume of a single fracturing stage or the contribution rate of a single fracturing stage to the total gas drainage.

[0003] With the further refinement of fracturing operation management, it is necessary to evaluate the gas extraction volume of a single fracturing segment. Based on this value, the fracturing operation effect of a single segment can be quantitatively evaluated, the effectiveness of fracturing operation can be assessed, and subsequent fracturing operations can be optimized.

[0004] Existing technologies primarily target production profile testing in surface horizontal wells. One approach involves injecting different tracers during the fracturing process of each fracturing section. The vented fluid is collected at the wellhead, and the gas / fluid production of each section is calculated through laboratory testing and analysis. This method requires selecting appropriate tracers based on formation conditions and necessitates prolonged monitoring and laboratory testing after production, making the process quite cumbersome. Another approach uses tubing or coiled tubing to carry testing instruments directly into the wellbore. This method relies on a surface coiled tubing installation vehicle powered directly from the ground. However, due to safety requirements in coal mines, the electrical equipment must obtain coal mine safety certification, and frequent power supply to the equipment in gas drainage boreholes poses certain safety hazards.

[0005] To address the above issues, there is an urgent need for a testing system and method for the gas extraction volume of each fracturing section in a segmented fracturing long borehole. This would enable the separate measurement of gas extraction volume in each fracturing section of a segmented fracturing long borehole in underground coal mines, improve the convenience of testing, and enhance its applicability under the working conditions and safety requirements of underground coal mines. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a testing system and method for the gas extraction volume of each fracturing section in a segmented fracturing long borehole, thereby solving the technical problem that existing gas extraction equipment cannot independently measure and evaluate the gas extraction volume of a single fracturing section in a directional long borehole in a coal mine.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] On one hand, the present invention provides a testing system for the gas extraction volume of each fracturing section of a segmented fracturing long borehole, including a data acquisition system and a water tank, a high-pressure pump and a mining continuous pipe trolley connected in sequence. The mining continuous pipe trolley includes a base plate, a pair of tracks are provided at the bottom of the base plate, a support rod is provided on the transverse front side of the top of the base plate, a rotating shaft is provided on the support rod, and a roller is rotatably provided on the rotating shaft.

[0009] The roller is wound with a continuous tube, and one end of the continuous tube is provided with a high-pressure rotary joint. The high-pressure rotary joint is connected to the high-pressure pump through a hose. Distributed pressure and temperature testing optical fibers are installed in the continuous tube.

[0010] A pair of hydraulic telescopic rods are also provided on the lateral rear side of the top of the base plate. A continuous tube injection structure is fixedly installed on the top of the hydraulic telescopic rods. The continuous tube injection structure includes a housing. Inside the housing, a pair of chains are arranged vertically and distributed laterally, with the chains moving in opposite directions. A continuous tube guide rail is provided at the axial front end of the housing, and a blowout preventer is provided at the axial rear end of the housing. The other end of the continuous tube passes through the continuous tube guide rail, the housing, and the pair of chains of the continuous tube injection structure in sequence before exiting from the blowout preventer. A tension gauge is also installed between the pair of chains of the continuous tube injection structure.

[0011] A motor unit and a controller are also provided in the horizontal center of the top of the base plate. The motor unit is electrically connected to the roller, the hydraulic telescopic rod and the chain. The motor unit and the controller are electrically connected.

[0012] It also includes a water jet guide shoe disposed at the other end of the continuous tube. The water jet guide shoe includes a connector, a flow pipe, a backward nozzle, and a forward nozzle connected in sequence. The backward nozzle and the forward nozzle are rotatably connected. The backward nozzle is provided with backward nozzles at equal intervals along the circumference. The orifices of the backward nozzles are axially backward. The forward nozzle is provided with grooves at equal intervals along the circumference. Each groove is provided with a forward nozzle. The orifices of the forward nozzles are axially forward.

[0013] This invention also includes the following technical features:

[0014] The rearward nozzle and the forward nozzle are rotatably connected by a bearing.

[0015] A pipe-laying device is provided on the top of the base plate, and the continuous pipe is wound around the roller after passing through the pipe-laying device.

[0016] On the other hand, the present invention provides a method for testing the gas extraction volume of each fracturing section in a segmented fracturing long borehole, using the aforementioned testing system for the gas extraction volume of each fracturing section in a segmented fracturing long borehole, specifically including the following steps:

[0017] Step 1: Collect casing solidification data, staged fracturing data, and gas extraction data for the target test borehole;

[0018] The casing borehole data includes the casing inner diameter d and the casing insertion depth;

[0019] The segmented fracturing data includes the number of fracturing segments N and the measurement depth L of each fracturing segment. (i) and vertical depth H (i) ;

[0020] The gas extraction data includes the total gas extraction volume q. 总 and gas relative density γ g ;

[0021] Step 2: Deploy a data acquisition system at the borehole opening of the target test borehole in the coal mine.

[0022] Step 2.1: Select a blowout preventer box with a matching size based on the inner diameter d of the sleeve;

[0023] Step 2.2: Using a coal mine underground railcar, all components of the test system for the gas extraction volume of each fracturing section of the segmented fracturing long borehole are delivered to the drilling site at the borehole opening of the target test borehole in the coal mine, and connected to obtain the test system for the gas extraction volume of each fracturing section of the segmented fracturing long borehole.

[0024] Step 2.3: Start the mine coiled tube car, pass the coiled tube through the coiled tube guide rail, the coiled tube injection structure and the blowout preventer box, connect the water jet guide shoe to the end of the coiled tube and put it into the casing orifice, and then mate the blowout preventer box with the casing.

[0025] Step 2.4: Connect the data acquisition system and the high-pressure rotary joint, and test the temperature and pressure signals of the optical fiber in the continuous tube until the data acquisition system can acquire temperature and pressure data.

[0026] Step 3: Restart the mine continuous tube car and use the continuous tube injection structure to push the continuous tube and water jet guide shoe into the target test borehole at a speed of 1-5 m / min, and make the end of the water jet guide shoe reach the predetermined depth.

[0027] The predetermined depth is 10 to 20 m below the depth of the first fracturing section in the target test borehole, and does not exceed the casing insertion depth;

[0028] The first fracturing section is the first fracturing section close to the bottom of the target test borehole;

[0029] During the pushing process, the tension gauge determines in real time whether the thrust in the continuous tube injected into the structure is below 50KN. If so, pushing continues; otherwise, the data acquisition system is disconnected, the high-pressure pump is connected to the high-pressure rotary joint on the drum via a hose, the high-pressure pump is started, and high-pressure water is injected into the continuous tube. The water jet guide shoe clears the obstruction at the front end. Pushing continues until the thrust is below 50KN until the predetermined depth is reached. The hose on the high-pressure rotary joint is then removed, and the data acquisition system is reconnected.

[0030] Step 4: Start the data acquisition system to obtain pressure and temperature data at each fracturing section location;

[0031] Step 5: Test complete, remove the data acquisition system;

[0032] Disconnect the data acquisition system and retrieve the continuous tube and water jet guide shoe outward at a speed of 1-5 m / min until they reach the orifice. Transport the mine continuous tube car, high-pressure pump, water tank and water jet guide shoe to the ground, and the test process ends.

[0033] During the recovery process, the tension gauge is used to determine in real time whether the tension in the coiled tube injection structure is lower than 50KN. If it is, the recovery continues; if not, the high-pressure pump is connected to the high-pressure rotary joint on the drum through a hose, the high-pressure pump is started, and high-pressure water is injected into the coiled tube. The water jet guide shoe is used to remove obstacles in the wellbore that affect the recovery of the coiled tube until the tension is lower than 50KN, then the recovery continues.

[0034] Step 6: Calculate the gas extraction volume of each fracturing section, and then calculate the gas extraction volume contribution rate of each fracturing section.

[0035] This invention also includes the following technical features:

[0036] Step 4 specifically includes the following steps:

[0037] Step 4.1: Test and record the pressure data P at each fracturing segment location at time t and (t+1) respectively. i (t) and P i (t+1);

[0038] in:

[0039] i represents the sequence number of the fracturing section, i = 1...N, and N represents the number of fracturing sections. The fracturing section closest to the bottom of the borehole is numbered 1, and from the bottom of the borehole to the borehole opening, they are numbered 2, 3, ..., N.

[0040] The time interval between (t+1) and time t is 15 to 30 minutes;

[0041] Step 4.2, calculate the relative pressure error ε at the i-th fracturing section according to the following formula. i ;

[0042]

[0043] Step 4.3, determine whether max(ε) is satisfied. i If ε ≤ 1, then the pressure is considered to have reached a stable state, and proceed to step 4.4; otherwise, let t = t + 1 and re-enter step 4.1.

[0044] Where ε is the error tolerance, and 0.001≤ε≤0.05;

[0045] Step 4.4: Record the pressure data P of the i-th fracturing segment at time (t+1). i and temperature data T i , where i = 1...N.

[0046] Step 6 specifically includes the following steps:

[0047] Step 6.1: Based on the collected segmented fracturing data, determine the location of each fracturing segment and the depth difference L between adjacent fracturing segments. (i)(i+1) ;

[0048] L (i)(i+1) =L i -L (i+1)

[0049] Step 6.2: Based on the collected segmented fracturing data, determine the location of each fracturing segment and the height difference H between adjacent fracturing segments. (i)(i+1) ;

[0050] H (i)(i+1) =H i -H (i+1)

[0051] Step 6.3, based on the temperature T at the i-th fracturing section i and the temperature T at the (i+1)th fracturing section i+1 Calculate the average temperature between two adjacent fracturing sections. Right now:

[0052]

[0053] Step 6.4, based on the pressure P at the i-th fracturing segment i and the pressure P at the (i+1)th fracturing stage (i+1) Calculate the gas flow rate q between the two fracturing sections. i ;

[0054] If H (i)(i+1) =H i -H (i+1) >0, then:

[0055]

[0056] If H (i)(i+1) =H i -H (i+1) =0, then:

[0057]

[0058] If H (i)(i+1) =H i -H (i+1) If <0, then:

[0059]

[0060] in:

[0061] P i (t) represents the pressure at the i-th fracturing segment location, in MPa;

[0062] P i (t+1) represents the pressure at the (i+1)th fracturing section, in MPa;

[0063] Let K represent the average temperature inside the casing between the i-th fracturing section and the (i+1)-th fracturing section;

[0064] This represents the average compressibility coefficient of the gas within the casing at the average pressure and average temperature between the i-th fracturing stage and the (i+1)-th fracturing stage;

[0065] q i m represents the gas extraction rate of the i-th fracturing stage under standard conditions. 3 / d;

[0066] P sc =0.101325MPa;

[0067] T sc =293K;

[0068] d represents the inner diameter of the casing, in meters (m).

[0069] γ gIndicates the relative density of a gas;

[0070] f represents the coefficient of friction, which is calculated using the Weymouth formula:

[0071]

[0072] S represents the coefficient, and:

[0073]

[0074] Step 6.5: Calculate the gas extraction rate q of the fractured section N using the following formula. N ;

[0075]

[0076] Step 6.6: Determine the gas extraction contribution rate C of the i-th fracturing stage according to the following formula. i :

[0077]

[0078] Compared with the prior art, the beneficial technical effects of this invention are:

[0079] (I) This invention solves the technical problem that existing gas extraction equipment cannot independently measure and evaluate the gas extraction volume of a single fracturing section in a directional long borehole by deploying distributed pressure and temperature testing optical fibers in a continuous tube, using a water tank, a high-pressure pump, and a mining continuous tube truck, and by using a data acquisition system to measure the pressure and temperature data of each fracturing section in real time. The testing process does not interfere with the normal gas extraction of the long borehole.

[0080] (II) The present invention uses the pressure and temperature data in the hole obtained by optical fiber testing to calculate the gas extraction volume of each fracturing section. It has fewer testing parameters and higher safety. Attached Figure Description

[0081] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0082] Figure 2 This is a front view schematic diagram of the continuous tube car for mining in this invention;

[0083] Figure 3 This is a side view of the continuous tube car structure used in mining according to the present invention;

[0084] Figure 4 This is a schematic diagram of the water jet guide shoe in this invention;

[0085] Figure 5 This is a schematic diagram of the end face structure of the target test borehole during the testing process.

[0086] The meanings of the labels in the diagram are as follows: 1-Data acquisition system, 2-Water tank, 3-High pressure pump, 4-Mine continuous tubing car, 5-Hose, 6-Casing;

[0087] 401-Base plate, 402-Crawler track, 403-Shaft, 404-Roller, 405-Continuous pipe, 406-High-pressure rotary joint, 407-Hydraulic telescopic rod, 408-Continuous pipe injection structure, 409-Motor unit, 4010-Controller, 4011-Water jet guide shoe, 4012-Pipe laying device, 4013-Support rod;

[0088] 40801 - Housing, 40802 - Chain, 40803 - Continuous tube guide rail, 40804 - Blowout preventer;

[0089] 401101-Connector, 401102-Flow pipe, 401103-Rear nozzle, 401104-Forward nozzle, 401105-Rear nozzle, 401106-Groove, 401107-Forward nozzle.

[0090] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0091] It should be noted that, unless otherwise specified, all components in this invention are those known in the art.

[0092] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0093] This invention provides a testing system for the gas extraction volume of each fracturing section in a segmented fracturing long borehole, such as... Figures 1 to 5 As shown, it includes a data acquisition system 1 and a water tank 2, a high-pressure pump 3 and a mining continuous pipe trolley 4 connected in sequence. The mining continuous pipe trolley 4 includes a base plate 401, a pair of tracks 402 at the bottom of the base plate 401, a support rod 4013 on the front side of the top of the base plate 401, a rotating shaft 403 on the support rod 4013, and a roller 404 rotatably mounted on the rotating shaft 403.

[0094] A continuous tube 405 is wound around the roller 404, and a high-pressure rotary joint 406 is provided at one end of the continuous tube 405. The high-pressure rotary joint 406 is connected to the high-pressure pump 3 through a hose 5. Distributed pressure and temperature testing optical fibers are installed in the continuous tube 405.

[0095] A pair of hydraulic telescopic rods 407 are also provided on the rear side of the top of the base plate 401. A continuous tube injection structure 408 is fixedly provided on the top of the hydraulic telescopic rods 407. The continuous tube injection structure 408 includes a housing 40801. A pair of chains 40802 distributed laterally are arranged vertically inside the housing 40801. The movement directions of the pair of chains 40802 are opposite. A continuous tube guide rail 40803 is provided at the front end of the housing 40801. A blowout preventer box 40804 is provided at the rear end of the housing 40801. The other end of the continuous tube 405 passes through the continuous tube guide rail 40803, the housing 40801, and the pair of chains 40802 in sequence and then exits from the blowout preventer box 40804. A tension gauge is also installed between the pair of chains 40802 of the continuous tube injection structure 408.

[0096] The top of the base plate 401 is also equipped with a motor unit 409 and a controller 4010 in the horizontal center. The motor unit 409 is electrically connected to the roller 404, the hydraulic telescopic rod 407 and the chain 40802. The motor unit 409 and the controller 4010 are electrically connected.

[0097] It also includes a water jet guide shoe 4011 disposed at the other end of the continuous tube 405. The water jet guide shoe 4011 includes a connector 401101, a flow pipe 401102, a backward nozzle 401103 and a forward nozzle 401104 connected in sequence. The backward nozzle 401103 and the forward nozzle 401104 are rotatably connected. The backward nozzle 401103 is provided with backward nozzles 401105 at equal intervals along the circumference. The orifices of the backward nozzles 401105 are axially backward. The forward nozzle 401104 is provided with grooves 401106 at equal intervals along the circumference. Each groove 401106 is provided with a forward nozzle 401107. The orifices of the forward nozzles 401107 are axially forward.

[0098] In the above technical solution, distributed pressure and temperature testing optical fibers are laid in the continuous tube, and the continuous tube 405 is pushed into the directional long borehole shaft using a water tank 2, a high-pressure pump 3, and a mining continuous tube trolley 4. The data acquisition system 1 measures the pressure and temperature data of each fracturing section in real time, and the testing process does not interfere with the normal gas extraction of the long borehole. This solves the technical problem that the existing gas extraction equipment cannot achieve independent measurement and evaluation of the gas extraction volume of a single fracturing section in a directional long borehole in a coal mine.

[0099] By using pressure and temperature data obtained from fiber optic testing, the gas extraction volume of each fracturing section can be calculated. This method requires fewer testing parameters and offers high safety.

[0100] The tension meter is used to measure the thrust or tension applied to the continuous tube by the continuous tube injection structure in real time; the motor unit 409 is used to drive the rotation of the drum 404, the extension and retraction of the hydraulic telescopic rod 407, and the movement of a pair of chains 40802; the controller 4010 is used to control the opening and closing of the motor unit 409.

[0101] The rear nozzle 401103 and the forward nozzle 401104 are rotatably connected by a bearing. The forward nozzle jet can rotate when breaking through obstacles, increasing the impact area and improving the efficiency of obstacle breaking.

[0102] A pipe arranger 4012 is provided on the top of the base plate 401. After the continuous pipe 405 passes through the pipe arranger 4012, it is wound onto the roller 404 to neatly wind the continuous pipe onto the roller.

[0103] This invention also provides a method for testing the gas extraction volume of each fracturing section in a segmented fracturing long borehole. The method employs a system for testing the gas extraction volume of each fracturing section in a segmented fracturing long borehole, and specifically includes the following steps:

[0104] Step 1: Collect casing solidification data, staged fracturing data, and gas extraction data for the target test borehole;

[0105] The casing borehole data includes the casing inner diameter d and the casing insertion depth;

[0106] Segmented fracturing data includes the number of fracturing segments N and the measurement depth L of each fracturing segment. (i) and vertical depth H (i) ;

[0107] Gas extraction data includes the total gas extraction volume q. 总 and gas relative density γ g ;

[0108] Step 2: Install data acquisition system 1 at the borehole of the target test borehole in the coal mine;

[0109] Step 2.1: Select a 40804 blowout preventer with a matching size based on the inner diameter d of the sleeve;

[0110] Step 2.2: Using a coal mine underground railcar, all components of the test system for the gas extraction volume of each fracturing section of the segmented fracturing long borehole are delivered to the drilling site at the borehole opening of the target test borehole in the coal mine, and connected to obtain the test system for the gas extraction volume of each fracturing section of the segmented fracturing long borehole.

[0111] Step 2.3: Start the mine continuous tube car 4, so that the continuous tube 405 passes through the continuous tube guide rail 40803, the shell 40801, the chain 40802 and the blowout preventer box 40804. After connecting the water jet guide shoe 4011 to the end of the continuous tube 405, insert it into the orifice of the casing 6. Then, mate the blowout preventer box 40804 with the casing 6.

[0112] Step 2.4: Connect the data acquisition system 1 and the high-pressure rotary joint 406, and test the temperature and pressure signals of the optical fiber in the continuous tube 405 until the data acquisition system 1 can acquire temperature and pressure data.

[0113] Step 3: Restart the mine continuous tube car 3, and use the continuous tube injection structure 408 to push the continuous tube 405 and the water jet guide shoe 4011 into the target test borehole at a speed of 1 to 5 m / min, and make the end of the water jet guide shoe 4011 reach the predetermined depth.

[0114] The predetermined depth is 10 to 20 m below the depth of the first fracturing section in the target test borehole, and does not exceed the casing insertion depth;

[0115] The first fracturing stage is the first fracturing stage close to the bottom of the target test borehole;

[0116] During the pushing process, the tension gauge determines in real time whether the thrust in the continuous tube injection structure 408 is below 50KN. If so, pushing continues; otherwise, the data acquisition system 1 is disconnected, and the high-pressure pump 3 is connected to the high-pressure rotary joint 406 on the drum 404 via the hose 5. The high-pressure pump 3 is started to inject high-pressure water into the continuous tube 405, and the water jet guide shoe 4011 is used to clear the obstruction at the front end. Pushing continues until the thrust is below 50KN until the predetermined depth is reached. The hose 5 on the high-pressure rotary joint 406 is then removed, and the data acquisition system 1 is reconnected.

[0117] Step 4: Start the data acquisition system 1 to acquire pressure and temperature data at each fracturing section location;

[0118] Step 5: Test complete, remove data acquisition system 1;

[0119] Disconnect the data acquisition system 1, and retrieve the continuous tube 405 and water jet guide shoe 4011 outward at a speed of 1-5 m / min until they reach the orifice. Transport the mine continuous tube trolley 4, high-pressure pump 3, water tank 2 and water jet guide shoe 4011 to the ground. The test process is over.

[0120] During the recovery process, the tension in the coiled tube injection structure 408 is judged in real time by the tension meter to see if it is lower than 50KN. If it is, the recovery continues; if not, the high-pressure pump 3 is connected to the high-pressure rotary joint 406 on the drum 404 through the hose 5, the high-pressure pump 3 is started, and high-pressure water is injected into the coiled tube 405. The water jet guide shoe 4011 is used to remove obstacles in the wellbore that affect the recovery of the coiled tube until the tension is lower than 50KN, and the recovery continues.

[0121] Step 6: Calculate the gas extraction volume of each fracturing section, and then calculate the gas extraction volume contribution rate of each fracturing section.

[0122] Specifically, step 4 includes the following steps:

[0123] Step 4.1: Test and record the pressure data P at each fracturing segment location at time t and (t+1) respectively. i (t) and P i (t+1);

[0124] in:

[0125] i represents the sequence number of the fracturing section, i = 1...N, and N represents the number of fracturing sections. The fracturing section closest to the bottom of the borehole is numbered 1, and from the bottom of the borehole to the borehole opening, they are numbered 2, 3, ..., N.

[0126] The time interval between (t+1) and time t is 15 to 30 minutes;

[0127] Step 4.2, calculate the relative pressure error ε at the i-th fracturing section according to the following formula. i ;

[0128]

[0129] Step 4.3, determine whether max(ε) is satisfied. i If ε ≤ 1, then the pressure is considered to have reached a stable state, and proceed to step 4.4; otherwise, let t = t + 1 and re-enter step 4.1.

[0130] Where ε is the error tolerance, and 0.001≤ε≤0.05;

[0131] Step 4.4: Record the pressure data P of the i-th fracturing segment at time (t+1). i and temperature data T i , where i = 1...N.

[0132] Specifically, step 6 includes the following steps:

[0133] Step 6.1: Based on the collected segmented fracturing data, determine the location of each fracturing segment and the depth difference L between adjacent fracturing segments. (i)(i+1) ;

[0134] L (i)(i+1) =L i -L (i+1)

[0135] Step 6.2: Based on the collected segmented fracturing data, determine the location of each fracturing segment and the height difference H between adjacent fracturing segments. (i)(i+1) ;

[0136] H (i)(i+1) =H i -H(i+1)

[0137] Step 6.3, based on the temperature T at the i-th fracturing section i and the temperature T at the (i+1)th fracturing section i+1 Calculate the average temperature between two adjacent fracturing sections. Right now:

[0138]

[0139] Step 6.4, based on the pressure P at the i-th fracturing segment i and the pressure P at the (i+1)th fracturing stage (i+1) Calculate the gas flow rate q between the two fracturing sections. i ;

[0140] If H (i)(i+1) =H i -H (i+1) >0, then:

[0141]

[0142] If H (i)(i+1) =H i -H (i+1) =0, then:

[0143]

[0144] If H (i)(i+1) =H i -H (i+1) If <0, then:

[0145]

[0146] in:

[0147] P i (t) represents the pressure at the i-th fracturing segment location, in MPa;

[0148] P i (t+1) represents the pressure at the (i+1)th fracturing section, in MPa;

[0149] The value in K represents the average temperature inside casing 6 between the i-th fracturing section and the (i+1)-th fracturing section.

[0150] This represents the average compressibility coefficient of the gas within the casing at the average pressure and average temperature between the i-th fracturing stage and the (i+1)-th fracturing stage;

[0151] q i m represents the gas extraction rate of the i-th fracturing stage under standard conditions.3 / d;

[0152] P sc =0.101325MPa;

[0153] T sc =293K;

[0154] d represents the inner diameter of the casing, in meters (m).

[0155] γ g Indicates the relative density of a gas;

[0156] f represents the coefficient of friction, which is calculated using the Weymouth formula:

[0157]

[0158] S represents the coefficient, and:

[0159]

[0160] Step 6.6: Calculate the gas extraction rate q of the fractured section N using the following formula. N ;

[0161]

[0162] Step 6.7, determine the gas extraction contribution rate C of the i-th fracturing stage according to the following formula. i :

[0163]

Claims

1. A method for testing the amount of gas extraction from each fracture section of a sectionally fractured long borehole, characterized in that, The test system for the gas extraction volume of each fracturing section of the segmented fracturing long borehole includes a data acquisition system (1) and a water tank (2), a high-pressure pump (3), and a mine continuous pipe trolley (4) connected in sequence. The mine continuous pipe trolley (4) includes a base plate (401) and a pair of tracks (402) are provided at the bottom of the base plate (401). The system is characterized in that a support rod (4013) is provided on the transverse front side of the top of the base plate (401), a rotating shaft (403) is provided on the support rod (4013), and a roller (404) is rotatably provided on the rotating shaft (403). The roller (404) is wound with a continuous tube (405), and one end of the continuous tube (405) is provided with a high-pressure rotary joint (406). The high-pressure rotary joint (406) is connected to the high-pressure pump (3) through a hose (5). The continuous tube (405) is provided with distributed pressure and temperature testing optical fibers. A pair of hydraulic telescopic rods (407) are also provided on the rear side of the top of the base plate (401). A continuous pipe injection structure (408) is fixedly provided on the top of the hydraulic telescopic rods (407). The continuous pipe injection structure (408) includes a housing (40801). A pair of chains (40802) are arranged vertically and horizontally inside the housing (40801). The movement directions of the pair of chains (40802) are opposite. The axial direction of the housing (40801) is... A continuous tube guide rail (40803) is provided at the front end, and a blowout preventer (40804) is provided at the axial rear end of the housing (40801); the other end of the continuous tube (405) passes through the continuous tube guide rail (40803), the housing (40801), and a pair of chains (40802) of the continuous tube injection structure (408) in sequence, and then exits from the blowout preventer (40804); a tension gauge is also installed between the pair of chains (40802) of the continuous tube injection structure (408); The base plate (401) is also provided with a motor unit (409) and a controller (4010) at the horizontal center of the top. The motor unit (409) is electrically connected to the roller (404), the hydraulic telescopic rod (407) and the chain (40802). The motor unit (409) and the controller (4010) are electrically connected. It also includes a water jet guide shoe (4011) disposed at the other end of the continuous tube (405). The water jet guide shoe (4011) includes a connector (401101), a flow pipe (401102), a backward nozzle (401103), and a forward nozzle (401104) connected in sequence. The backward nozzle (401103) and the forward nozzle (401104) are rotatably connected. The backward nozzle (401103) is provided with backward nozzles (401105) at equal intervals along the circumference. The orifice of the backward nozzle (401105) is axially rearward. The forward nozzle (401104) is provided with grooves (401106) at equal intervals along the circumference. Each groove (401106) is provided with a forward nozzle (401107). The orifice of the forward nozzle (401107) is axially forward. The method specifically includes the following steps: Step 1: Collect casing solidification data, staged fracturing data, and gas extraction data for the target test borehole; The lower casing hole-fixing data includes casing inner diameter d and casing running depth; The segment fracturing data includes segment number N of fracturing segments and measured depth of each fracturing segment and vertical depth ; The gas extraction data includes total gas extraction amount and gas relative density ; Step 2: Arrange a data acquisition system (1) at the borehole of the target test borehole in the coal mine. Step 2.1, according to the inside diameter of the casing d Select a blowout preventer (40804) of a size to fit. Step 2.2: Using a coal mine underground railcar, all components of the test system for the gas extraction volume of each fracturing section of the segmented fracturing long borehole are delivered to the drilling site at the borehole opening of the target test borehole in the coal mine, and connected to obtain the test system for the gas extraction volume of each fracturing section of the segmented fracturing long borehole. Step 2.3: Start the mine coiled tube car (4), so that the coiled tube (405) passes through the coiled tube guide rail (40803), the shell (40801), the chain (40802) and the blowout preventer (40804). After connecting the water jet guide shoe (4011) to the end of the coiled tube (405), insert it into the opening of the casing (6). Then, mate the blowout preventer (40804) with the casing (6). Step 2.4: Connect the data acquisition system (1) and the high-pressure rotary joint (406) to test the temperature and pressure signals of the optical fiber in the continuous tube (405) until the data acquisition system (1) can acquire temperature and pressure data. Step 3: Restart the mine continuous tube car (4), and use the continuous tube injection structure (408) to push the continuous tube (405) and water jet guide shoe (4011) into the target test borehole at a speed of 1~5 m / min, and make the end of the water jet guide shoe (4011) reach the predetermined depth. The predetermined depth is 10-20m below the depth of the first fracturing section in the target test borehole, and does not exceed the casing insertion depth; The first fracturing section is the first fracturing section close to the bottom of the target test borehole; During the pushing process, the tension meter determines in real time whether the thrust in the continuous tube injection structure (408) is lower than 50KN. If so, the pushing continues; if not, the data acquisition system (1) is disconnected, and the high-pressure pump (3) is connected to the high-pressure rotary joint (406) on the drum (404) through the hose (5). The high-pressure pump (3) is started to inject high-pressure water into the continuous tube (405), and the water jet guide shoe (4011) is used to clear the obstacles at the front end. The pushing continues until the thrust is lower than 50KN until the predetermined depth is reached. The hose (5) on the high-pressure rotary joint (406) is removed, and the data acquisition system (1) is connected. Step 4: Start the data acquisition system (1) to obtain pressure and temperature data at each fracturing section location; Step 5, test ends, remove data acquisition system (1); Disconnect the data acquisition system (1), and retrieve the continuous tube (405) and water jet guide shoe (4011) outward at a speed of 1~5 m / min until it reaches the orifice. Transport the mine continuous tube car (4), high pressure pump (3), water tank (2) and water jet guide shoe (4011) to the ground. The test process ends. During the recovery process, the tension in the coiled tube injection structure (408) is judged in real time by the tension meter to see if it is lower than 50KN. If it is, the recovery continues; if not, the high pressure pump (3) is connected to the high pressure rotary joint (406) on the drum (404) through the hose (5), the high pressure pump (3) is started, and high pressure water is injected into the coiled tube (405). The water jet guide shoe (4011) is used to remove obstacles in the wellbore that affect the recovery of the coiled tube until the tension is lower than 50KN, and the recovery continues. Step 6: Calculate the gas extraction volume of each fracturing section, and then calculate the gas extraction volume contribution rate of each fracturing section.

2. The method of claim 1, wherein, The rearward nozzle (401103) and the forward nozzle (401104) are rotatably connected by bearings.

3. The method of claim 1, wherein, The bottom plate (401) is provided with a pipe laying device (4012) at the top, and the continuous pipe (405) is wound around the roller (404) after passing through the pipe laying device (4012).

4. The method of claim 1, wherein, Step 4 specifically includes the following steps: Step 4.1, test the pressure data of each fracture segment position at time t and (t+1) respectively and ; in: i represents the sequence number of the fracturing section, i=1...N, and N represents the number of fracturing sections. The fracturing section closest to the bottom of the borehole is 1, and the sections from the bottom of the borehole to the borehole opening are 2, 3, ..., N. The time interval between (t+1) and time t is 15 to 30 minutes; Step 4.2, calculate the pressure relative error at the i-th fracturing segment according to the following formula ; Step 4.3, judge whether the following condition is satisfied If yes, it is considered that the pressure reaches stability, and enter Step 4.4, otherwise let t = t + 1, and re-enter Step 4.1; wherein, is the error tolerance, and 0.001≤ ≤0.05; Step 4.4, record the pressure data of the i-th fracturing section at (t+1) time and temperature data where i = 1...N.

5. The method of claim 1, wherein, Step 6 specifically includes the following steps: Step 6.

1. Based on the collected fracturing data, determine the location of each fracture segment and the depth difference between adjacent fracture segments ; Step 6.2, based on the collected fracturing data, determine the location of each fracture segment and the height difference between adjacent fracture segments ; Step 6.3, based on the temperature at the i-th fracturing section and the ( i +1) Temperature at the fracturing section Calculate the average temperature between two adjacent fracturing sections. ,Right now: Step 6.4, based on the pressure at the i-th fracturing segment and the pressure at the (i+1)th fracturing segment Calculate the gas flow rate between the two fracturing sections. ; If then: If then: If then: in: P; represents the pressure at the i-th fracture segment location, MPa; P(i+1) represents the pressure at the location of the (i+1)th fracturing section, MPa; Tavg(i+1) represents the average temperature within the casing (6) between the ith and (i+1)th fracturing stages, K; This represents the average compressibility coefficient of the gas within the casing at the average pressure and average temperature between the i-th fracturing stage and the (i+1)-th fracturing stage; represents the amount of gas extraction of the i-th fracturing section under standard conditions, m 3 / d; ； ； Indicates the inner diameter of the casing, in meters (m). represents the relative density of the gas; coefficient of friction, calculated according to the Weymouth formula: represents a coefficient, and: Step 6.6, Calculate the gas extraction amount of the fracturing section N by the following formula ; Step 6.

7. Determine the gas extraction contribution rate of the i-th fracturing section according to the following formula : 。

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