Detection method of wellbore overflow detection system

Abstract

The present invention provides a wellbore overflow detection system and detection method, which are used to solve the problem of gas intrusion detection in the prior art. To achieve the above-mentioned purpose and other related purposes, the present invention provides a wellbore overflow detection system, which is used to detect the gas intrusion position of a drilling system. The drilling system includes: a hollow drill pipe and a vertical tube, the outer wall of the vertical tube is used to cooperate with the inner wall of the wellbore, and the outer diameter of the hollow drill pipe is smaller than the inner diameter of the vertical tube; the vertical tube is provided with a second slurry outlet pipe; the wellbore overflow detection system includes: a first pressure sensor provided on the hollow drill pipe, a second throttle valve provided on the second slurry outlet pipe, a second pressure sensor provided on the second slurry outlet pipe, and a gas-liquid flowmeter provided on the second slurry outlet pipe. It can solve the problem of gas intrusion position detection.

Description

Technical Field

[0001] The present invention relates to the field of well drilling, and in particular to a detection method of a wellbore overflow detection system. Background Art

[0002] During the drilling process, factors such as the excitation pressure generated during drilling, low drilling fluid density, and abnormal formation pressure can cause the formation pressure to exceed the annular pressure, leading to the intrusion of formation gas to the bottomhole and causing gas invasion. Under all operating conditions, when gas invasion occurs, a negative pressure differential exists between the annulus and the formation. If gas invasion is not detected promptly and effective measures are not taken, the negative pressure differential between the annulus and the formation will further increase as the gas migrates toward the wellhead, exacerbating the gas invasion and worsening it, potentially leading to accidents such as blowouts. Under normal circumstances, gas invasion occurs at the bottomhole or at the casing shoe, but when drilling into unusually complex formations, gas invasion can occur anywhere in the openhole. From a drilling safety perspective, the earlier gas invasion is detected, the better. Accurately determining the location of the invasion facilitates effective measures to suppress it, fundamentally preventing blowouts and ensuring normal drilling progress.

[0003] Currently, a variety of methods are available for determining gas invasion at drilling sites, including drilling fluid pool level detection, DC index, shale density, torque meter detection, acoustic transit time, and pump-stroke methods. The most typical methods are acoustic transit time and pump-stroke. The basic principle of the acoustic transit time method is that the propagation speed of sound waves in gas-containing drilling fluid differs from that in gas-free drilling fluid. When gas invasion does not occur, the propagation speed of sound waves in the drilling fluid within the drill pipe is equal to that in the drilling fluid within the annulus. When gas invasion occurs, the drilling fluid in the annulus contains gas. The time required for sound waves emitted from the bottomhole to reach the surface through the gas-containing drilling fluid in the annulus differs from the time required to reach the surface through the gas-free drilling fluid within the drill pipe. This time difference can be used to determine whether gas invasion has occurred underground. The basic principle of the pump-pulse method is that when the drilling mud pump is working, the piston in the pump generates a pressure pulse. This pressure pulse enters the circulation system, propagates in the drill string, downhole power drilling tools, test-while-drilling system, and drill bit nozzle, and then returns to the ground along the annulus. This method uses the pressure pulse generated by the mud pump during operation as a ground pressure pulse generator.

[0004] However, gas intrusion detection in the drilling industry, both domestically and internationally, is limited to gas intrusion identification. There is no method for quickly and accurately determining the location of gas intrusion during drilling, failing to meet the requirements for precise, low-flow, unconventional well killing. Accurately identifying the location of gas intrusion not only facilitates analysis of complex formation structures but also enables the implementation of effective measures, such as increasing drilling fluid density, increasing backpressure, or installing casing to isolate the intrusion, to suppress it. Accurately determining the location of gas intrusion has become a pressing challenge in drilling engineering. Therefore, a method and device for quickly and accurately detecting the location of gas intrusion is highly desirable. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a detection method of a wellbore overflow detection system, so as to solve the problem of gas intrusion detection in the prior art.

[0006] To achieve the above-mentioned and other related objectives, the present invention provides a detection method of a wellbore overflow detection system for detecting the gas intrusion position of a drilling system, wherein the drilling system comprises:

[0007] A hollow drill pipe and a vertical cylinder, wherein the outer wall of the vertical cylinder is used to cooperate with the inner wall of the wellbore, and the outer diameter of the hollow drill pipe is smaller than the inner diameter of the vertical cylinder;

[0008] The vertical cylinder is provided with a second slurry outlet pipe;

[0009] The wellbore overflow detection system includes:

[0010] A first pressure sensor is arranged on the hollow drill rod, a second throttle valve is arranged on the second slurry outlet pipe, a second pressure sensor is arranged on the second slurry outlet pipe, and a gas-liquid flow meter is arranged on the second slurry outlet pipe.

[0011] Optionally, a pulp separator is provided on the vertical cylinder, and the pulp separator includes:

[0012] A sleeve, wherein annular plates are provided along the annular edges near the inner side at the upper and lower ends of the sleeve;

[0013] An expansion core, the expansion core is made of rubber and includes an arc-shaped arch ring, the arc-shaped arch ring protrudes toward the center line of the sleeve, the concave side of the arc-shaped arch ring and the inner wall of the sleeve form a hydraulic channel, and the two ends of the arc-shaped arch ring are respectively clamped on the inner side of the ring plate;

[0014] A hydraulic port is provided on the side wall of the sleeve, and is used to introduce hydraulic fluid into the hydraulic channel and to discharge the hydraulic fluid from the hydraulic channel. The hydraulic fluid in the hydraulic channel can expand and deform the arc-shaped arch ring portion.

[0015] A connecting tube is provided at the lower end of the sleeve, a pulp separation port is provided on the side wall of the connecting tube, and a first pulp outlet pipe is provided on the pulp separation port.

[0016] Optionally, the expansion core further includes locking rings located at the upper and lower ends of the arc-shaped arch ring, the two locking rings are respectively fixed to the arc-shaped arch ring, and the locking rings are locked and matched with the inner side of the ring plate.

[0017] A detection method comprises the following steps:

[0018] The gas invasion judgment step is to judge whether gas invasion occurs according to the gas-liquid flow rate in the second slurry outlet pipe recorded by the gas-liquid flow meter. When the gas is detected by the gas-liquid flow meter, gas invasion occurs at the bottom of the well.

[0019] A detection method comprises the following steps:

[0020] Adjust the opening of the second throttle valve. The pressure wave generated by the action of the hydraulic throttle valve is the wave source. The wave propagates along the annulus to the bottom of the well and returns to the wellhead in two loops: the hollow drill pipe and the annulus.

[0021] Based on the different propagation speeds of pressure waves in gas-containing drilling fluid and gas-free drilling fluid, whether gas invasion has occurred is judged according to the time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave. When there is a time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave, gas invasion has occurred at the bottom of the well.

[0022] Optionally, the following steps are also included to determine the location of the gas intrusion:

[0023] When gas intrusion is detected, the opening of the second throttle valve is adjusted. The pressure wave generated by the hydraulic throttle valve is the wave source. The wave propagates along the annulus to the bottom of the well and returns to the wellhead in two loops: the hollow drill pipe and the annulus.

[0024] Based on the different propagation speeds of pressure waves in gas-containing drilling fluid and non-gas-containing drilling fluid, the location where gas invasion occurs is determined according to the time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave.

[0025] Optionally, when gas intrusion occurs, the opening of the first throttle valve is reduced.

[0026] Optionally, the gas intrusion position determination step includes:

[0027] The annulus is discretized into n grids, the wellhead is the first grid, the well depth H0 = 0m, the wave velocity of the first grid is c0, and the well depth H1 and wave velocity c1 of the next grid can be iteratively calculated based on the well depth and wave velocity of the wellhead using the Runge-Kutta method, and the well depth H of the i-th grid is obtained in turn. i and wave speed c i , calculate the propagation time of the pressure wave in the corresponding grid according to the well depth and wave velocity of the i-th grid. The sum of the propagation time of the pressure wave in the first i (i≤n) grids in the annulus is T1. The time required for the pressure wave in the hollow drill pipe to propagate from the well depth corresponding to the i-th grid in the annulus to the wellhead is T2. The time difference of the pressure wave is △T. The time difference between the pressure wave propagation in the two paths detected by the first pressure sensor and the second pressure sensor is T c ;

[0028] in:

[0029]

[0030] Where c is the propagation velocity of the pressure wave in the single-phase drilling fluid without gas;

[0031] ΔT = T1 - T2;

[0032] When |T c -(T1-T2)|<δ, δ——Calculation accuracy of gas leakage point.

[0033] Optionally, δ is between 0.01 and 0.1.

[0034] Optionally, the adjustment of a throttle valve is stopped until the time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave is zero.

[0035] As described above, the wellbore overflow detection system and detection method of the present invention have at least the following beneficial effects:

[0036] This detection system is equipped with a gas-liquid flowmeter so that it can directly determine whether there is gas intrusion at the bottom of the well through the gas-liquid flowmeter. By setting up a first pressure sensor and a second pressure sensor, the pressure of the hollow drill pipe and the vertical cylinder can be measured respectively, and the opening of the second throttle valve is adjusted to generate a pressure wave. The pressure wave is affected by the gas intrusion and has different wave velocities. According to the time difference between the pressure fluctuations of the first pressure sensor and the second pressure sensor, it can also be used to determine whether gas intrusion has occurred and the location of the gas intrusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Shown is a schematic diagram of a first embodiment of a drilling system according to the present invention.

[0038] Figure 2 FIG. 1 is a schematic diagram showing a second embodiment of a drilling system according to the present invention.

[0039] Table 1 shows the oil well parameters and drilling fluid properties of the embodiment of the present invention.

[0040] Table 2 shows the test data and test results of the embodiment of the present invention.

[0041] Component number description

[0042] 1 sleeve

[0043] 2 Core expansion

[0044] 11 Ring Plate

[0045] 21 Arc Arch

[0046] 12 hydraulic ports

[0047] 13 Connecting tube

[0048] 131 pulp outlet

[0049] 22 card slots

[0050] 3 Hollow drill rod

[0051] 4 vertical tubes

[0052] 5 wells

[0053] 1311 First slurry outlet pipe

[0054] 13111 First Throttle Valve

[0055] 41 Second slurry outlet pipe

[0056] 411 Second Throttle Valve

[0057] 31 First pressure sensor

[0058] 32 Second pressure sensor

[0059] 412 flow meter DETAILED DESCRIPTION

[0060] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0061] See also Figures 1 to 2 . It should be noted that the structures, proportions, sizes, etc. shown in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0062] The following embodiments are for illustration only and can be combined with each other, and are not limited to the contents presented in the following single embodiments.

[0063] See also Figure 1The present invention provides an embodiment of a wellbore overflow detection system for detecting the location of gas intrusion in a drilling system. The drilling system includes: a hollow drill pipe 3 and a vertical tube 4, wherein the outer wall of the vertical tube 4 is configured to cooperate with the inner wall of a wellbore 5, and the outer diameter of the hollow drill pipe 3 is smaller than the inner diameter of the vertical tube 4; and a second slurry discharge pipe 41, which is disposed on the vertical tube 4 and communicates with the space between the inner wall of the vertical tube 4 and the outer wall of the hollow drill pipe 3. The provision of the second slurry discharge pipe 41 increases the amount of slurry discharge, thereby enhancing the safety of the entire drilling system. The second slurry discharge pipe 41 is provided with a second throttle valve 411. The provision of the second throttle valve 411 controls the opening and closing of the second slurry discharge pipe 41, as well as the degree of opening and closing, thereby adjusting the discharge volume and releasing different pressure levels within the vertical tube 4. The hollow drill pipe 3 is provided with a first pressure sensor 31, and the second slurry discharge pipe 41 is provided with a second pressure sensor 32. It can monitor the pressure of the mud when entering the hollow drill pipe 3, and can also monitor the pressure of the mud from the second slurry outlet pipe 41. By comparing them, it can be determined whether gas intrusion has occurred. Optionally, a gas-liquid flowmeter 412 is also provided on the second slurry outlet pipe 41. The gas-liquid flowmeter 412 can measure the mud flow in the second slurry outlet pipe 41 and the gas flow when gas intrusion occurs. After the computer collects the pressure data, mud flow data, and gas flow data, it can calculate the specific gas intrusion position, thereby controlling the opening of the throttle valve for adjustment, making the control more accurate and improving the installation performance of the drilling system.

[0064] The wellbore overflow detection system includes:

[0065] A first pressure sensor 31 is provided on the hollow drill rod 3 , a second throttle valve 411 is provided on the second slurry outlet pipe 41 , a second pressure sensor 32 is provided on the second slurry outlet pipe 41 , and a gas-liquid flow meter 412 is provided on the second slurry outlet pipe 41 .

[0066] This detection system is equipped with a gas-liquid flowmeter so that it can directly determine whether there is gas intrusion at the bottom of the well through the gas-liquid flowmeter. By setting up a first pressure sensor and a second pressure sensor, the pressure of the hollow drill pipe and the vertical cylinder can be measured respectively, and the opening of the second throttle valve is adjusted to generate a pressure wave. The pressure wave is affected by the gas intrusion and has different wave velocities. According to the time difference between the pressure fluctuations of the first pressure sensor and the second pressure sensor, it can also be used to determine whether gas intrusion has occurred and the location of the gas intrusion.

[0067] See also Figure 2The present invention provides another embodiment of a wellbore overflow detection system, wherein a slurry separator is provided on the vertical cylinder 4, comprising: a sleeve 1 and an expansion core 2, wherein an annular plate 11 is provided at the upper and lower ends of the sleeve 1 along the circumferential edge near the inner side; the expansion core 2 is made of rubber material, and the rubber material can be deformed and expanded to achieve sealing, and comprises an arc-shaped arch ring 21, the arc-shaped arch ring 21 protrudes toward the center line side of the sleeve 1, the concave side of the arc-shaped arch ring 21 and the inner wall of the sleeve 1 form a hydraulic channel, and the two ends of the arc-shaped arch ring 21 are respectively clamped on the inner side of the annular plate 11; a hydraulic port 12 is opened on the side wall of the sleeve 1, and the hydraulic port 12 is used to introduce hydraulic fluid into the hydraulic channel and to discharge the hydraulic fluid in the hydraulic channel, and the hydraulic fluid in the hydraulic channel can partially expand and deform the arc-shaped arch ring 21; a connecting tube 13 is provided at the lower end of the sleeve 1, and a slurry separator 131 is provided on the side wall of the connecting tube 13. The slurry separator is installed at the upper end of the vertical cylinder 4, and the connecting cylinder 13 and the vertical cylinder 4 are coaxially detachably connected. The detachable connection is specifically through a flange structure. The detachable structure can realize the repeated use of the slurry separator and replacement in case of failure, especially the expansion core 2 part, which is in squeeze contact with the outer wall of the hollow drill rod 3 and is more easily damaged than the outer shell. When the expansion core 2 is damaged, the expansion core 2 can be replaced and then installed on the vertical cylinder 4 for use. The hollow drill rod 3 axially passes through the arc arch ring 21; the slurry outlet 131 is provided with a first slurry outlet pipe 1311. When in use, the connecting cylinder 13 is fixedly connected to the upper end of the vertical cylinder mentioned in the following drilling system. The specific connection method can be The expansion core 2 is configured as an arc-shaped arch ring 21 structure. When subjected to the tension of the hydraulic fluid, it expands, achieving uniform circumferential squeezing of the hollow drill pipe mentioned in the drilling system, thereby achieving sealing. A slurry outlet 131 is also provided, so that it can achieve sealing while also ensuring the discharge of mud. The slurry outlet 131 here can be used as the main mud discharge channel or as an auxiliary mud discharge channel. When there is no gas intrusion, it can be closed. When gas intrusion occurs, it is opened to discharge mud and adjust the pressure in the vertical tube, which can increase the range of pressure regulation, thereby ensuring the safety and reliability of drilling operations. The hydraulic pressure in and out of the hydraulic port 12 can be pumped out and back to the hydraulic source by a hydraulic pump from the hydraulic source component hydraulic oil. Optionally, a first throttle valve 13111 is provided on the first slurry outlet pipe 1311. The first throttle valve 13111 controls the opening and closing of the first slurry outlet pipe 1311, as well as the degree of opening and closing, thereby controlling the flow of slurry, thereby regulating the pressure in the vertical cylinder 4. The first throttle valve 13111 and the second throttle valve 411 can be hydraulically driven. Hydraulic drive can withstand greater pressure and has higher reliability.

[0068] See also Figure 2In one embodiment of the expansion core 2, the expansion core 2 further includes retaining rings 22 located at the upper and lower ends of the arcuate arch ring 21. The two retaining rings 22 are respectively fixed to the arcuate arch ring 21, and the retaining rings 22 engage with the inner side of the ring plate 11. The retaining rings 22 can be integrally formed with the arcuate arch ring 21. The provision of the retaining rings 22 can make the retaining structure at both ends of the arcuate arch ring 21 more reliable, and the contact area between the retaining rings 22 and the ring plate 11 and the inner side wall of the sleeve 1 is larger.

[0069] A detection method embodiment 1 includes the following steps:

[0070] The first step is to determine whether gas invasion has occurred based on the gas-liquid flow rate in the second slurry outlet pipe recorded by the gas-liquid flow rate. When the gas-liquid gas-liquid flowmeter detects gas, gas invasion has occurred at the bottom of the well. When the gas-liquid gas-liquid flowmeter does not detect gas, gas invasion has not occurred at the bottom of the well.

[0071] In the second step, when gas intrusion is detected in the first step, the opening of the second throttle valve is reduced. The pressure wave generated by the hydraulic throttle valve is the wave source. The wave propagates along the annulus to the bottom of the well and returns to the wellhead in two loops: the hollow drill pipe and the annulus.

[0072] Based on the different propagation speeds of pressure waves in gas-containing drilling fluid and non-gas-containing drilling fluid, the location where gas invasion occurs is determined according to the time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave.

[0073] In a third step, optionally, when the time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave is zero, stop adjusting a throttle valve.

[0074] A second embodiment of a detection method includes the following steps:

[0075] The first step is to reduce or increase the opening of the second throttle valve. The pressure wave generated by the hydraulic throttle valve is the wave source. The wave propagates along the annulus to the bottom of the well and returns to the wellhead in two loops: the hollow drill pipe and the annulus.

[0076] Based on the different propagation speeds of pressure waves in gas-containing drilling fluid and gas-free drilling fluid, whether gas invasion has occurred is judged according to the time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave. When there is a time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave, gas invasion has occurred at the bottom of the well.

[0077] In the second step, when gas intrusion is detected in the first step, the opening of the second throttle valve is reduced. The pressure wave generated by the hydraulic throttle valve is the wave source. The wave propagates along the annulus to the bottom of the well and returns to the wellhead in two loops: the hollow drill pipe and the annulus.

[0078] Based on the different propagation speeds of pressure waves in gas-containing drilling fluid and non-gas-containing drilling fluid, the location where gas invasion occurs is determined according to the time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave.

[0079] In a third step, optionally, when the time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave is zero, stop adjusting a throttle valve.

[0080] The gas intrusion position determination steps in the above two embodiments include:

[0081] The space between the hollow drill pipe and the vertical cylinder is the annulus, which is discretized into n grids. The wellhead is the first grid. The well depth H0 of the first grid is 0m, and the wave velocity of the first grid is c0. According to the well depth and wave velocity of the wellhead, the Runge-Kutta method can be used to iteratively calculate the well depth H1 and wave velocity c1 of the next grid, and the well depth H of the i-th grid is obtained in turn. i and wave speed c i , the propagation time of the pressure wave in the corresponding grid is calculated according to the well depth and wave velocity of the i-th grid. The sum of the propagation time of the pressure wave in the first i (i≤n) grids in the annulus is T1, as shown in formula (1); the time required for the pressure wave in the hollow drill pipe to propagate from the well depth corresponding to the i-th grid in the annulus to the wellhead is T2, as shown in formula (2); the pressure wave time difference is △T, and the time difference between the pressure wave propagation in the two paths detected by the first pressure sensor and the second pressure sensor is T c ;

[0082] The time difference T between the two pressure sensors detecting the pressure wave propagating in the two paths is calculated as follows: c If the difference between the iteratively calculated wave velocity time difference ΔT meets the accuracy requirement δ in equation (4), the calculation ends. At this time, H obtained by equation (5) is the annular air intrusion position. Otherwise, i = i + 1, and the next grid is entered. The above steps are repeated until the accuracy requirement is met.

[0083]

[0084] ΔT=T1-T2 (3)

[0085] |T c -(T1-T2)|<δ (4)

[0086]

[0087] Where T1 is the propagation time of the pressure wave returning along the annulus, s; T2 is the propagation time of the pressure wave returning along the drill string, s; H i ——The height of the i-th grid, m; c i——the propagation velocity of the pressure wave in the ith grid, m / s; c——the propagation velocity of the pressure wave in the single-phase drilling fluid without gas, m / s; △T——the calculated return time difference of the pressure wave, s; T c ——Return time difference of pressure wave detected by pressure sensor, s; δ——Calculation accuracy of gas invasion leakage point, m; H——Length of well section above gas invasion position, m.

[0088] δ can be between 0.01 and 0.1. Within this range, positioning accuracy can be effectively guaranteed while avoiding excessive calculations, thereby improving response speed.

[0089] Table 1 below shows the relevant parameters of drilling. Table 2 below shows the data of the time difference of the pressure waves detected by the first pressure sensor and the second pressure sensor, as well as the liquid flow rate and gas flow rate detected by the gas-liquid flowmeter, and the detection results output based on these parameters and the above detection method when δ is 0.01.

[0090] Table 1

[0091] parameter Numerical parameter Numerical Drill collar length (m) 200 Mud pump displacement (L / s) 37 Drill rod length (m) 3800 String elastic modulus (Pa) <![CDATA[2.07×10 11 ]]> Drill bit diameter (m) 0.2159 <![CDATA[Drilling fluid density (kg / m 3 )]]> 1460 Drill pipe outer diameter (m) 0.127 Poisson's ratio of the string 0.3 Drill pipe inner diameter (m) 0.1086 Drilling fluid compressibility (1 / kPa) <![CDATA[5.7×10 -8 ]]> Drill collar outer diameter (m) 0.1778 Surface temperature (℃) 25 Drill collar inner diameter (m) 0.078 Ground atmospheric pressure (MPa) 0.101 Drill pipe roughness (mm) 0.0154 Well wall roughness (mm) 0.1

[0092] Table 2

[0093]

[0094] In summary, the present invention:

[0095] (1) Accurate detection: Although conventional gas intrusion detection methods can determine whether gas intrusion has occurred, they cannot accurately detect the location of the gas intrusion. The present invention is based on the pressure wave time difference method, which not only realizes the function of conventional gas intrusion detection, but also can accurately determine the location of the gas intrusion, making up for the defect of the existing device that cannot determine the location of the gas intrusion, and can effectively improve work efficiency.

[0096] (2) High immediacy: The device of the present invention uses a pressure sensor and a gas-liquid flowmeter to detect changes in pressure and flow at the inlet and outlet positions in real time, which not only improves the accuracy of gas intrusion detection, but also realizes real-time monitoring of the drilling process, effectively improving the sensitivity of detection.

[0097] (3) Low equipment cost: The device of the present invention does not require large-scale improvements to the well site. The hydraulic throttle valve at the wellhead is used as the fluctuation source, and a pressure sensor and a gas-liquid flow meter are used to detect the wellhead pressure and flow. The data transmission line transmits the detection data to the industrial control computer, and the industrial control computer performs annular space hydraulic calculations on various parameters to realize the detection of the gas intrusion position.

[0098] (4) Simple operation: Just turn on the industrial computer, connect the data transmission lines, input the relevant parameters, and observe the output results on the industrial computer screen to complete the gas intrusion detection and gas intrusion location determination.

[0099] (5) Wide range of applications: The method and device provided by the present invention can be widely used to detect the gas intrusion position during drilling processes such as underbalanced drilling, unconventional well pressure drilling, and micro-flow drilling.

[0100] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A detection method for a wellbore overflow detection system, characterized in that: Used to detect the gas invasion position of a drilling system, the drilling system comprising: A hollow drill pipe and a vertical cylinder, wherein the outer wall of the vertical cylinder is used to cooperate with the inner wall of the wellbore, and the outer diameter of the hollow drill pipe is smaller than the inner diameter of the vertical cylinder; The vertical cylinder is provided with a second slurry outlet pipe; The wellbore overflow detection system includes: a first pressure sensor provided on the hollow drill rod, a second throttle valve provided on the second slurry outlet pipe, a second pressure sensor provided on the second slurry outlet pipe, and a gas-liquid flow meter provided on the second slurry outlet pipe; The vertical cylinder is provided with a pulp separator, which comprises: A sleeve, wherein annular plates are provided along the annular edges near the inner side at the upper and lower ends of the sleeve; An expansion core, the expansion core is made of rubber and includes an arc-shaped arch ring, the arc-shaped arch ring protrudes toward the center line of the sleeve, the concave side of the arc-shaped arch ring and the inner wall of the sleeve form a hydraulic channel, and the two ends of the arc-shaped arch ring are respectively clamped on the inner side of the ring plate; A hydraulic port is provided on the side wall of the sleeve, and is used to introduce hydraulic fluid into the hydraulic channel and to discharge the hydraulic fluid from the hydraulic channel. The hydraulic fluid in the hydraulic channel can expand and deform the arc-shaped arch ring portion. The lower end of the sleeve is provided with a connecting tube, the side wall of the connecting tube is provided with a pulp outlet, and the pulp outlet is provided with a first pulp outlet pipe; The expansion core further includes a retaining ring located at the upper and lower ends of the arc-shaped arch ring, the two retaining rings are respectively fixed to the arc-shaped arch ring, and the retaining rings are engaged with the inner side of the ring plate; The detection method of the detection system includes the following steps: a gas intrusion judging step, judging whether gas intrusion has occurred based on the gas-liquid flow rate in the second slurry outlet pipe recorded by the gas-liquid flow meter; when the gas-liquid flow meter detects gas, gas intrusion has occurred at the bottom of the well; Adjust the opening of the second throttle valve. The pressure wave generated by the action of the hydraulic throttle valve is the wave source. The wave propagates along the annulus to the bottom of the well and returns to the wellhead in two loops: the hollow drill pipe and the annulus. Based on the different propagation speeds of pressure waves in gas-containing drilling fluid and gas-free drilling fluid, whether gas invasion has occurred is determined based on the time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave. When there is a time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave, gas invasion has occurred at the bottom of the well; It also includes the steps for determining the location of gas intrusion: When gas intrusion is detected, the opening of the second throttle valve is adjusted. The pressure wave generated by the hydraulic throttle valve is the wave source. The wave propagates along the annulus to the bottom of the well and returns to the wellhead in two loops: the hollow drill pipe and the annulus. Based on the different propagation speeds of pressure waves in gas-containing drilling fluid and non-gas-containing drilling fluid, the location where gas invasion occurs is determined according to the time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave.

2. The detection method according to claim 1, wherein: When gas intrusion occurs, the opening of the first throttle valve is reduced.

3. The detection method according to claim 1, wherein: The steps for determining the location of gas intrusion include: The annulus is discretized into n grids, the wellhead is the first grid, the well depth H0 = 0m, the wave velocity of the first grid is c0, and the well depth H1 and wave velocity c1 of the next grid can be iteratively calculated based on the well depth and wave velocity of the wellhead using the Runge-Kutta method, and the well depth H of the i-th grid is obtained in turn. i and wave speed c i , calculate the propagation time of the pressure wave in the corresponding grid according to the well depth and wave velocity of the i-th grid. The sum of the propagation time of the pressure wave in the first i (i≤n) grids in the annulus is T1. The time required for the pressure wave in the hollow drill pipe to propagate from the well depth corresponding to the i-th grid in the annulus to the wellhead is T2. The time difference of the pressure wave is △T. The time difference between the pressure wave propagation in the two paths detected by the first pressure sensor and the second pressure sensor is T c ; in: Where c is the propagation velocity of the pressure wave in the single-phase drilling fluid without gas; ΔT = T1 - T2; When |T c -(T1-T2)|<δ, δ——Calculation accuracy of gas leakage point.

4. The detection method according to claim 3, wherein: δ is between 0.01 and 0.

1.

5. The detection method according to claim 2, wherein: When the time difference between the first pressure sensor and the second pressure sensor receiving the pressure wave becomes zero, the adjustment of the throttle valve is stopped.

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