An accident well directional measurement system and method based on spatial magnetic field information

Abstract

The application discloses a kind of based on spatial magnetic field information accident well directional measurement system and method, wherein the system includes: excitation source, loop electrode located near the wellhead of accident well, downhole three electrodes and probe pipe in rescue well;The probe pipe includes acceleration sensor and two magnetic sensors, wherein the output of the excitation source is connected with the loop electrode, the downhole three electrodes, for power supply;The downhole three electrodes are used to inject alternating current to surrounding formation, and the loop formed by the downhole three electrodes, the loop electrode and the space of earth forms convergent current on the metal casing in the accident well;Two magnetic sensors are used to detect the magnetic field generated by the current on the metal casing, and together with the information collected by the acceleration sensor, for analysis and processing in turn to determine the orientation of accident well.The simple, accurate and fast directional measurement method of accident well can be measured.

Description

Technical Field

[0001] This invention relates to the field of downhole detection technology, and relates to, but is not limited to, a directional measurement system and method for accident wells based on spatial magnetic field information. Background Technology

[0002] In recent years, well blowouts have occurred frequently, and given the complex downhole environment, the rapid and efficient control of blowouts has become increasingly important. Currently, rescue well technology is one of the effective means to resolve blowouts. Determining the location information of the rescue well and the affected well is a key technical issue in the rescue process. Compared to other positioning technologies, electromagnetic positioning technology for rescue wells is not limited by factors such as geological formations, has low technical costs, good equipment stability, and broad application prospects.

[0003] Current methods for measuring the location of faulty wells primarily involve using Measurement While Drilling (MWD) instruments to measure wellbore trajectory and tool attitude information, including well inclination, well inclination azimuth, and tool face (device angle). MWD equipment typically includes a geomagnetic sensor and a tilt sensor. The geomagnetic sensor measures the direction and intensity of the downhole magnetic field, while the tilt sensor measures the wellbore's tilt angle and direction. By combining the geomagnetic sensor's measurements of the downhole magnetic field's direction and intensity, the wellbore's orientation can be calculated under the influence of the Earth's magnetic field. However, because the Earth's magnetic field varies at different locations and times, instrument calibration at the wellhead is necessary to ensure accuracy and precision.

[0004] In addition, many scholars have calculated the orientation of the accident well by processing magnetic field signals to calculate the basic well inclination data of the rescue well. Then, based on the relationship between the magnetic field and the well axis directions of the two wells, they determine the relative orientation of the measurement point of the rescue well and the target point of the accident well. In this calculation method, the measurement unit typically consists of a three-axis fluxgate sensor and a three-axis accelerometer. First, the acceleration information is used to calculate the well inclination angle and azimuth angle of the rescue well. Then, the spatial relationship between the current direction on the casing of the accident well and the magnetic induction intensity direction measured by the sensor, both of which are perpendicular to the direction vector from the probe to the measured point on the casing, is used to determine the relative orientation of the casing of the accident well relative to the casing. This method requires prior knowledge of the orientation of the accident well and assumes that the orientation will not change, making it unsuitable for all situations. Furthermore, this method often involves continuously moving the position of the detection unit, lowering it to multiple specified depths within the rescue well, and collecting magnetic field strength data at multiple points. By comparing the magnetic field strength values ​​at multiple locations, a model is established to determine the casing orientation. This method typically requires additional conditions, such as the orientation of the accident well. The accuracy of the measurement results is related to the number of measuring points, and increasing the number of measuring points is necessary to improve the accuracy. Furthermore, because this method requires continuous movement of the detection unit, the depth data from lowering the equipment is often inaccurate during actual well logging, with significant errors in distance across multiple locations, leading to noticeable errors in the orientation algorithm. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide an accident well orientation measurement system and method based on spatial magnetic field information, which solves the technical problems of existing accident well orientation methods, such as cumbersome single-sensor measurement process, inaccurate measurement results, and small measurement range of horizontally arranged dual sensors.

[0006] The technical solution of this invention is implemented as follows:

[0007] In a first aspect, embodiments of the present invention provide an accident well orientation measurement system based on spatial magnetic field information, comprising: an excitation source, a loop electrode located near the wellhead of the accident well, a downhole three-electrode located in the rescue well, and a probe; the probe includes an accelerometer and two magnetic sensors; wherein, the output of the excitation source is connected to the loop electrode and the downhole three-electrode for power supply; the downhole three-electrode is used to inject alternating current into the surrounding formation, and the loop formed by the downhole three-electrode, the loop electrode, and the earth space generates a converging current on the metal casing in the accident well; the two magnetic sensors are used to detect the magnetic field information generated by the current on the metal casing, and together with the data collected by the accelerometer, are used for analysis and processing to determine the orientation of the accident well.

[0008] In some possible embodiments, the system further includes a data transmission module and a host computer. The data transmission module is used to transmit the detected magnetic field information and acceleration data to the host computer, and the host computer is used to analyze the magnetic field information and acceleration data to calculate the location information of the accident well.

[0009] In some possible embodiments, the two magnetic sensors are two triaxial fluxgate sensors, arranged at fixed intervals in the probe, for detecting magnetic field information of two adjacent points at fixed positions.

[0010] In a second aspect, embodiments of the present invention provide a method for directional measurement of accident wells based on spatial magnetic field information, applied to the accident well directional measurement system described in the first aspect above, the method comprising:

[0011] The excitation source is controlled to supply power to the downhole three electrodes to generate an electric field on the metal casing in the accident well and transmit it to the loop electrode through the formation loop; wherein, the formation loop is a loop formed by the downhole three electrodes, the loop electrode and the earth space; the magnetic field information generated by the current on the metal casing is detected by two magnetic sensors in the rescue downhole probe and data is collected by an acceleration sensor; the acquired magnetic field information and acceleration data are analyzed and processed to calculate the azimuth information of the accident well.

[0012] In some possible embodiments, the step of analyzing and processing the acquired magnetic field information and acceleration data to calculate the orientation information of the accident well includes: determining the rotation matrix from the probe coordinate system to the geomagnetic coordinate system based on the magnetic field information and the acceleration data; performing coordinate transformation on the magnetic field vector detected by the magnetic sensor based on the rotation matrix; determining the orientation of the accident well; solving for the direction vector of the accident well relative to the magnetic sensor; and converting the direction vector into corresponding angle information as the orientation information of the accident well relative to the rescue well.

[0013] In some possible embodiments, determining the rotation matrix from the probe coordinate system to the geomagnetic coordinate system based on the magnetic field information and the acceleration data includes: calculating the angles between the three axes of the probe coordinate system and the corresponding three axes of the geomagnetic coordinate system using the detection component value of any of the magnetic sensors and the gravitational acceleration component obtained by the acceleration sensor; constructing a sub-matrix for the rotation process around the axis corresponding to each angle, and then combining them to obtain the rotation matrix.

[0014] In some possible embodiments, determining the orientation of the accident well includes: constructing two sets of equations based on the principle that the magnetic field directions measured by two magnetic sensors are perpendicular to the current direction of the metal casing in the accident well; and determining the current flow direction of the metal casing by solving the two sets of equations, which is taken as the orientation of the accident well.

[0015] In some possible embodiments, solving the direction vector of the accident well relative to the magnetic sensor includes: constructing two sets of relational expressions based on the positional relationship between the shortest distance vector of the casing in the accident well relative to each of the magnetic sensors and the direction vector obtained by the corresponding magnetic sensors and the orientation of the metal casing, respectively; and solving the two sets of relational expressions to obtain the direction vector of the accident well relative to each of the sensors.

[0016] In some possible embodiments, converting the direction vector into the corresponding angle information includes: using true north as a reference point, using the tangent function, and combining the magnetic declination data of the measurement location, calculating the radian information in the magnetic north direction, and finally converting the direction vector into the angle information.

[0017] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0018] This invention provides a system for directional measurement of accident wells based on spatial magnetic field information. This system determines the relative positions of the rescue well and the accident well based on the magnetic field distribution around the metal casing of the accident well using two magnetic sensors. It eliminates the need to estimate the current intensity on the metal casing of the accident well and provides good data results even at long distances, considering the actual operating environment. Furthermore, it provides a simple, accurate, and rapid method for directional measurement of accident wells, solving the current difficulties in directional measurement while improving measurement accuracy at longer detection distances. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0020] Figure 1 This invention provides a schematic diagram of an accident well directional measurement system based on spatial magnetic field information.

[0021] Figure 2 A dual-sensor orientation scene diagram for the accident well orientation measurement system based on spatial magnetic field information provided by this invention;

[0022] Figure 3 A flowchart illustrating a method for directional measurement of accident wells based on spatial magnetic field information, provided in an embodiment of the present invention;

[0023] Figure 4 A diagram showing the rotation of the coordinate axes from the probe coordinate system to the geomagnetic coordinate system provided by this invention;

[0024] Figure 5 This is a flowchart of the algorithm for calculating the location information of accident wells and rescue wells provided by the present invention;

[0025] Figure 6 The overall logic flowchart of the accident well directional measurement method based on spatial magnetic field information provided in the embodiments of the present invention;

[0026] Figure label:

[0027] 1-Excitation source; 2-Loop electrode; 3-Downhole three electrodes; 4-Insulated cable; 5-Probe; 6-Rescue well; 7-Metal casing; 8-Accident well; 9-Induced magnetic field; 10-Casing current; 14-Total magnetic field acquired by the first fluxgate sensor; 15-Total magnetic field acquired by the second fluxgate sensor; 16-Shortest distance vector from the first fluxgate sensor to the metal casing; 17-Shortest distance vector from the second fluxgate sensor to the metal casing; 18-Acceleration sensor. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0030] It should be noted that the terms "first, second, and third" used in the embodiments of the present invention are only used to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first, second, and third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of the present invention described herein can be implemented in an order other than that illustrated or described herein.

[0031] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which these embodiments of the invention pertain. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0032] This invention provides a system for directional measurement of accident wells based on spatial magnetic field information. Figure 1 This is a schematic diagram of an accident well directional measurement system provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the accident well orientation measurement system 100 includes: an excitation source (1), a loop electrode (2) located near the wellhead of the accident well (8), a downhole three-electrode (3) located in the rescue well, and a probe (5); the probe (5) includes an accelerometer and two magnetic sensors; wherein, the output of the excitation source (1) is connected to the loop electrode (2) and the downhole three-electrode (3) for power supply; the downhole three-electrode (3) is used to inject alternating current into the surrounding formation, and the loop formed by the downhole three-electrode (3), the loop electrode (2), and the earth space generates a converging current on the metal casing (7) in the accident well (8); the two magnetic sensors are used to detect the magnetic field information generated by the current on the metal casing (7), and together with the data collected by the accelerometer, are used for analysis and processing to determine the orientation of the accident well.

[0033] Here, the downhole probe (5) is used to detect the gravity field, geomagnetic field, and low-frequency alternating magnetic field generated by the low-frequency alternating current accumulated on the casing of the accident well at the downhole probe location. The main control computer supplies power to the downhole three electrodes (3) through the control system of the excitation source (1). The electric field generated by the downhole three electrodes flows to the loop electrode (2) through the formation loop, such as... Figure 1 As shown, during this process, when a metal casing (7) appears in the accident well (8), a converging current (9) will be generated on the casing (7). The converging current will generate a magnetic field (10), and the magnetic field data will be acquired by the magnetic sensor in the probe (5).

[0034] Given the complexity of well operations, the accident well directional measurement system provided by this invention can greatly save manpower and time costs. The system can provide directional results in a single measurement without the need for multiple round trips to measure different points, which better meets the urgent needs of rescue missions. At the same time, since the accident well directional measurement method based on this system can obtain the corresponding directional results without multiple downhole measurements, it can greatly improve the efficiency of well operations and buy time for sealing accident wells.

[0035] In some embodiments, the system further includes a data transmission module and a host computer. The data transmission module is used to transmit the detected magnetic field information and acceleration data to the host computer, and the host computer is used to analyze the magnetic field information and acceleration data to calculate the location information of the accident well.

[0036] Here, the data transmission module can be an armored cable, such as... Figure 1 As shown, the downhole injection three-electrode (3) and the probe (5) are connected by an armored cable (4) and placed in the rescue well (6). The probe (5) detects the magnetic field generated by the current on the metal casing (7) and transmits it to the host computer through the armored cable (4) together with the information collected by the acceleration sensor in the probe (5). The host computer determines the location of the accident well by analyzing the magnetic field signals of the two sensors.

[0037] In some embodiments, the two magnetic sensors are two triaxial fluxgate sensors, which are arranged at fixed intervals in the probe to detect magnetic field information of two adjacent points with fixed positions.

[0038] Here, the probe (5) includes two triaxial fluxgate sensors and one accelerometer (18). The first fluxgate sensor collects the signal of the total magnetic field (14); the second fluxgate sensor collects the signal of the total magnetic field (15), such as... Figure 2 As shown, the shortest distance vector (16) from the first fluxgate sensor to the metal sleeve (7) and the shortest distance vector (17) from the second fluxgate sensor to the metal sleeve (7) are shown.

[0039] In practice, a triaxial accelerometer is used to detect the triaxial gravitational acceleration at the downhole probe. Both the triaxial fluxgate sensor and the triaxial accelerometer are installed in a non-magnetic metal bracket inside the non-magnetic casing of the probe; the non-magnetic casing of the probe is a sealed structure. The triaxial fluxgate sensor is used to detect the combined magnetic field value of the triaxial geomagnetic field at the downhole probe and the low-frequency alternating magnetic field generated by the low-frequency alternating current accumulated on the casing of the emergency well, which is used to determine the distance and orientation between the downhole probe and the casing of the emergency well.

[0040] The main principle of the orientation algorithm provided by this invention is as follows: the orientation of the metal casing is determined based on the fact that the magnetic field direction measured by the two fluxgate sensors in the rescue well is perpendicular to the current direction on the metal casing in the accident well. Then, the orientation vector between the accident well and the probe is determined based on the shortest distance vector between the metal casing and each sensor in the rescue well and the positional relationship that the magnetic field directions obtained by the metal casing and the fluxgate sensors in the accident well are perpendicular to each other.

[0041] This invention determines the relative directions of the rescue well and the accident well based on the magnetic field distribution around the metal casing in the accident well. Furthermore, considering the actual operating environment, it provides good data results even at long distances. It eliminates the need for repeated measurements, simplifies the calculations, and only requires the magnetic field direction information from two sensors and the acceleration information fixed to them to determine the orientation of the metal casing in the accident well. This allows for the determination of the shortest distance vector from each sensor to the metal casing in the accident well, i.e., the direction from each sensor to the accident well.

[0042] Figure 3 This is a flowchart illustrating a method for directional measurement of accident wells based on spatial magnetic field information, provided in an embodiment of the present invention. This method is applied to the aforementioned directional measurement system for accident wells. Figure 3 As shown, the method includes at least the following steps:

[0043] Step S310: Control the excitation source to supply power to the downhole three electrodes to generate an electric field on the metal casing in the accident well and transmit it to the loop electrode through the formation loop.

[0044] Here, the formation loop is the loop formed by the downhole three electrodes, the loop electrode, and the ground space. The main control computer supplies power to the downhole three electrodes through the control system of the excitation source. The electric field generated by the downhole three electrodes flows to the loop electrode through the formation loop. During this process, when a metal casing appears in the accident well, a converging current will be generated on the casing, and the converging current will generate a magnetic field.

[0045] Step S320: The magnetic field information generated by the current on the metal casing is detected by two magnetic sensors in the rescue well probe, and data is collected by an accelerometer.

[0046] Here, the magnetic field data is acquired by the triaxial fluxgate sensor in the probe and transmitted to the host computer along with the accelerometer through the data acquisition module. The host computer analyzes the acquired magnetic field data and calculates the location information of the accident well.

[0047] Step S330: Analyze and process the acquired magnetic field information and acceleration data to calculate the location information of the accident well.

[0048] Here, based on the mutually orthogonal positional relationship of the direction vector of the radiation magnetic field of the rescue well, the direction vector of the induced current in the accident pipe, and the direction vector of the accident well relative to the rescue well, the orientation information of the accident well relative to the rescue well is quickly and accurately determined by using the magnetic field information of two fixed measurement points and the well inclination information of the rescue well.

[0049] In this embodiment of the invention, the relative positions of the rescue well and the accident well are determined based on the magnetic field distribution around the metal casing of the accident well using two magnetic sensors. This eliminates the need to estimate the current intensity on the metal casing of the accident well, and, considering the actual operating environment, provides good data results even at long distances. This method is simple to implement and easy to operate, enabling multiple measurements at a single point downhole to determine the results, thus improving orientation accuracy and measurement efficiency. Compared to traditional accident well positioning methods, it does not require knowledge of the electrode's emission current, thereby reducing the influence of the emission system on the final orientation result and further improving the accuracy of the results.

[0050] The procedure for calculating the location of the accident well and the rescue well is as follows: Figure 4 First, the rotation matrix from the probe coordinate system to the geomagnetic coordinate system needs to be determined using data collected by the accelerometer and fluxgate sensor. Then, the magnetic field vector of the probe coordinate system is converted to the geomagnetic coordinate system. Next, the orientation of the accident well and the direction vector of the accident well relative to the sensor are determined according to the orientation principle. Finally, the direction vector is combined with the magnetic declination data of the test scene to convert it into angle information, so as to achieve accurate orientation of the accident well.

[0051] In some possible embodiments, step S330 above, "analyzing and processing the acquired magnetic field information and acceleration data to calculate the azimuth information of the accident well," further includes the following steps:

[0052] Step S331: Based on the magnetic field information and the acceleration data, determine the rotation matrix from the probe coordinate system to the geomagnetic coordinate system.

[0053] It should be noted that, under normal circumstances, due to factors such as engineering operations during drilling, the probe coordinate system is frequently changing, while the geomagnetic coordinate system remains fixed. For ease of engineering construction, it is necessary to transform the probe coordinate system to the geomagnetic coordinate system using a rotation matrix R. For this equipment, the first step is to use a three-axis fluxgate sensor and an accelerometer to calculate the angles between the three axes of the probe coordinate system and the three axes of the geomagnetic coordinate system.

[0054] It is important to note that the probe coordinate system frequently changes due to engineering operations during drilling, while the geomagnetic coordinate system remains fixed. For ease of construction, it is necessary to transform the probe coordinate system to the geomagnetic coordinate system using a rotation matrix. For this equipment, the first step is to use a three-axis fluxgate sensor and an accelerometer to calculate the angles between the three axes of the probe coordinate system and the three axes of the geomagnetic coordinate system.

[0055] In some embodiments, step S331 above can be implemented by the following process: using the detection component value of any of the magnetic sensors and the gravitational acceleration component obtained by the accelerometer to calculate the size of each included angle between the three axes of the probe coordinate system and the corresponding three axes of the geomagnetic coordinate system; constructing a sub-matrix for the rotation process around the axis corresponding to each included angle, and then combining them to obtain the rotation matrix.

[0056] For ease of understanding, let's assume that under initial conditions, the probe's coordinate system OXYZ and the geomagnetic coordinate system ONED have the same coordinate axes, meaning the two axes coincide (OX ~ ON, OY ~ OE, OZ ~ OD). Here, OX points north, OY points east, and OZ points to the ground; the three axes are mutually perpendicular, forming a left-handed coordinate system. Figure 5 The diagram shown is a rotation diagram of the coordinate axes from the probe coordinate system to the geomagnetic coordinate system provided by the present invention. This diagram was created to facilitate a better understanding of the construction process of the rotation matrix.

[0057] First, rotate the geographic coordinate system ONED around OZ as the central axis to obtain OX1Y1Z1 by a rotation angle of ψ°. Next, rotate OX1Y1Z1 around OY1 as the central axis to obtain OX2Y2Z2. Finally, rotate OX2Y2Z2 around OX2 as the central axis to obtain OX3Y3Z3. Referring to this process, consider OX3Y3Z3 as the probe coordinate system. By reversing the above process, rotating around the three axes by three angles φ°, θ°, and ψ° respectively, the probe coordinate system can be transformed into the geomagnetic coordinate system.

[0058] In mathematics, Euler angles are commonly used to represent the rotation of one coordinate system relative to another reference coordinate system in three-dimensional space. For the application scenario of this invention, the Euler angles required to transform the probe coordinate system to the geomagnetic coordinate system are φ°, θ°, and ψ°. These angles are calculated using accelerometers and fluxgate sensors within the probe.

[0059] Given that the components of the gravitational acceleration vector obtained by the accelerometer are Gx, Gy, and Gz, and the three-axis magnetic field components measured by the two three-axis fluxgate sensors are B... 1x B 1y B 1z B 2x B 2y B 2z .

[0060] First, the gravitational acceleration component obtained by the accelerometer and the magnetic field component value of any fluxgate sensor are used to calculate the three corresponding angles between the geomagnetic coordinate system (NED axis) and the probe coordinate system (xyz axis), which are the Euler angles required to construct the rotation matrix.

[0061]

[0062] It should be noted that the above calculation only provides a basic framework for understanding. In practical applications, factors such as changes in the three-axis correspondence of accelerometers and fluxgate sensors may exist, requiring appropriate adjustments to the Euler angle calculation process for different situations.

[0063] Based on the Euler angles obtained from the above analysis, a rotation matrix is ​​constructed for the rotation process around the axis corresponding to each Euler angle.

[0064] Construct a rotation matrix R for the process of rotating φ° around the x-axis. x (φ) is:

[0065]

[0066] Construct a rotation matrix R for the process of rotating θ° around the y-axis. y (θ) is:

[0067]

[0068] Construct a rotation matrix R for the process of rotating ψ° around the z-axis. z (ψ) is:

[0069]

[0070] The rotation matrix R for coordinate system transformation is:

[0071] R = R x (φ)R y (θ)R z (ψ) Formula (5);

[0072] In actual calculations, since the axes of the two fluxgate sensors correspond one-to-one, the rotation matrix of either fluxgate sensor can be determined individually. The above calculation only performed the rotation matrix calculation for one of the fluxgate sensors. The parameters of the rotation matrix for the other fluxgate sensor are the same as described above.

[0073] Step S332: Perform coordinate transformation on the magnetic field vector detected by the magnetic sensor based on the rotation matrix.

[0074] Here, the rotation matrix R is used to transform the magnetic field vector of either of the two fluxgate sensors in the probe coordinate system to the geomagnetic coordinate system.

[0075]

[0076] Wherein, B1 and B2 are the magnetic field vectors in the geomagnetic coordinate system after coordinate transformation of the magnetic field vectors of the first fluxgate sensor and the second fluxgate sensor, respectively.

[0077] Step S333: Determine the orientation of the accident well.

[0078] Here, since the direction of the accident well and the direction of the casing in the accident well are the same, and since the downhole three electrodes are working, the direction of the current generated on the casing of the accident well is the same as the direction of the casing of the accident well, thus determining the direction of the current flow on the casing of the accident well, which in turn determines the direction of the accident well itself.

[0079] In some implementations, step S133 is carried out by the following process: using the principle that the magnetic field directions measured by the two magnetic sensors are perpendicular to the current direction of the metal casing in the accident well, two sets of equations are constructed; by solving the two sets of equations, the current flow direction of the metal casing is determined and used as the direction of the accident well itself.

[0080] Using the right-hand screw theorem, the direction of the current on the fault well casing is perpendicular to the magnetic field measured by the two triaxial fluxgate sensors on the probe. Based on this principle, the orientation of the fault well can be determined by using the relationship between the magnetic field values ​​B1 and B2 received by the two triaxial fluxgate sensors and the orientation vector n2 of the fault well casing.

[0081]

[0082] This invention does not require repeated measurements and is simple to calculate. It only requires the magnetic field direction information of two sensors and the acceleration information fixed to them to determine the direction of the metal casing in the accident well.

[0083] Step S334: Solve for the direction vector of the accident well relative to the magnetic sensor.

[0084] Here, once the direction of the current in the casing of the accident well is determined, the direction of the accident well casing relative to the sensor can be determined.

[0085] Based on the positional relationship between the shortest distance vector of the casing in the accident well relative to each of the magnetic sensors and the direction vector obtained by the corresponding magnetic sensors and the orientation of the metal casing, two sets of relational formulas are constructed; the direction vector of the accident well relative to each of the sensors is obtained by solving the two sets of relational formulas.

[0086] The vectors of the shortest distance between the faulty well casing and the sensors are perpendicular to both the sensor output and the current in the faulty well casing. Using the right-hand rule, the vectors of the faulty well casing at its shortest distance from both sensors can be estimated. and They are respectively:

[0087]

[0088] in These are the output direction vectors of the two and three-axis fluxgate sensors in the probe, respectively.

[0089] This method allows for multiple measurements at a single point downhole to reduce errors, avoiding the cumulative error effect caused by errors in position measurement and other factors in previous methods, thus improving the overall orientation accuracy.

[0090] Step S335: Convert the direction vector into corresponding angle information, which serves as the orientation information of the accident well relative to the rescue well.

[0091] Here, the direction information is still vector data and needs to be converted into angle information.

[0092] In some implementations, with true north as the reference point, the tangent function is used in conjunction with the magnetic declination data of the measurement location to calculate the radian information in the magnetic north direction, and finally the direction vector is converted into the angle information.

[0093] The relative positions of the rescue well and the accident well are determined by the magnetic field distribution around the metal casing of the accident well using two magnetic sensors. This eliminates the need to estimate the current intensity on the metal casing of the accident well, and also provides good data results even at long distances, considering the actual operating environment.

[0094] This invention utilizes the pairwise orthogonal positional relationships of the radiated magnetic field direction vector of the rescue well, the induced current direction vector in the casing of the accident well, and the direction vector of the accident well relative to the rescue well. By employing the magnetic field information from two fixed measurement points and the well inclination information of the rescue well, it rapidly and accurately determines the azimuth information of the accident well relative to the rescue well. This solves the problems of existing orientation methods requiring multiple round trips, resulting in significant time and labor costs and large measurement errors. Furthermore, this detection method is simple to implement and easy to operate, enabling multiple measurements at a single point downhole to determine the result, thereby improving orientation accuracy and measurement efficiency.

[0095] The above provides a detailed description of the implementation examples of the method and system of this invention, and elaborates on the specific operation methods. The entire flowchart is shown below. Figure 6 As shown. Extensive testing has proven that the method of this invention does not require prior knowledge of the accident well's orientation and yields relatively accurate results. It should be noted that this invention works best in environments with minimal surface impact. For those skilled in the art, variations in the specific implementation methods and application scope will exist based on the steps of this invention.

[0096] In this invention, the relative directions of the rescue well and the accident well are determined based on the magnetic field distribution around the metal casing in the accident well. Furthermore, considering the actual operating environment, good data results are achieved even at long distances. Repeated measurements are unnecessary, and the calculations are simple. The orientation of the metal casing in the accident well can be determined using only the magnetic field direction information from two sensors and the acceleration information fixed to them. This allows for the determination of the shortest distance vector from each sensor to the metal casing in the accident well, i.e., the direction from each sensor to the accident well. The specific effects are summarized as follows:

[0097] 1. Given the complexity of well operations, this method can greatly save manpower and time costs. A single measurement can provide orientation results without the need for multiple round trips for measurement, which is more in line with the urgent needs of rescue missions.

[0098] 2. Since this method does not require multiple downhole measurements to obtain the corresponding directional results, it can greatly improve the efficiency of surface work and buy time for plugging the accident well;

[0099] 3. This method allows for multiple measurements at a single point downhole to reduce errors, avoiding the cumulative error effect caused by errors in position measurement and other factors in previous methods, thus improving the overall orientation accuracy.

[0100] The embodiments described in this invention are only used to illustrate the relevant algorithm flow and implementation principle of this invention, and are not intended to limit the scope of protection of this invention. All equivalent substitutions, changes, and improvements made based on the technical solutions of this invention should be included within the scope of protection of this invention.

[0101] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of the invention, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the invention. The sequence numbers of the above-described embodiments of the invention are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0102] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0103] In the several embodiments provided by this invention, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0104] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units. They may be located in one place or distributed across multiple network units. Some or all of the units may be selected to achieve the purpose of the embodiments of the present invention, depending on actual needs.

[0105] In addition, in the various embodiments of the present invention, each functional unit can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be implemented in hardware or in the form of hardware plus software functional units.

[0106] The methods disclosed in the several method embodiments provided by this invention can be arbitrarily combined without conflict to obtain new method embodiments.

[0107] The features disclosed in the several method or device embodiments provided by the present invention can be arbitrarily combined without conflict to obtain new method or device embodiments.

[0108] The above description is merely an embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for directional measurement of accident wells based on spatial magnetic field information, characterized in that, This invention relates to a directional measurement system for accident wells. The system includes an excitation source, a loop electrode located near the wellhead of the accident well, a downhole three-electrode system located in the rescue well, and a probe. The probe includes an accelerometer and two magnetic sensors. The output of the excitation source is connected to the loop electrode and the downhole three-electrode system for power supply. The downhole three-electrode system injects alternating current into the surrounding formation, and the loop formed by the downhole three-electrode system, the loop electrode, and the ground space generates a converging current on the metal casing in the accident well. The two magnetic sensors detect the magnetic field information generated by the current on the metal casing, and this information, along with data collected by the accelerometer, is used for analysis and processing to determine the location of the accident well. The two magnetic sensors are two triaxial fluxgate sensors, arranged at fixed intervals in the probe, used to detect the magnetic field information of two adjacent points at fixed locations. The method for directional measurement of the accident well includes: The excitation source is controlled to supply power to the downhole three electrodes to generate an electric field on the metal casing in the accident well and transmit it to the loop electrode through the formation loop; wherein, the formation loop is a loop formed by the downhole three electrodes, the loop electrode and the earth space; The magnetic field information generated by the current on the metal casing is detected by two magnetic sensors in the rescue well probe, and data is collected by an accelerometer. Based on the magnetic field information and the acceleration data, a rotation matrix from the probe coordinate system to the geomagnetic coordinate system is determined; based on the rotation matrix, a coordinate transformation is performed on the magnetic field vector detected by the magnetic sensor. ;in, For rotation matrix, , These are the magnetic field vectors in the geomagnetic coordinate system after coordinate transformation of the magnetic field vectors of the two magnetic sensors, respectively. These are the magnetic field components of the first magnetic sensor along the x, y, and z axes in the probe coordinate system; These are the magnetic field components of the second magnetic sensor along the x, y, and z axes in the probe coordinate system, respectively. Determine the orientation of the accident well; solve for the direction vector of the accident well relative to the magnetic sensor; convert the direction vector into corresponding angle information, which serves as the orientation information of the accident well relative to the rescue well; The determination of the orientation of the accident well includes: using the principle that the magnetic field directions measured by two magnetic sensors are perpendicular to the current direction of the metal casing in the accident well, the following two sets of equations are constructed: ; The direction vector of the accident well casing is given; by solving the two sets of equations, the current flow direction of the metal casing is determined and used as the direction of the accident well itself. The step of solving the direction vector of the accident well relative to the magnetic sensor includes: Based on the positional relationship between the shortest distance vector of the casing in the accident well relative to each of the magnetic sensors and the direction vector obtained by the corresponding magnetic sensors and the orientation of the metal casing, the following two sets of relationships are constructed: ; , These are the direction vectors output by the two magnetic sensors in the probe; and These are the vectors representing the shortest distances between the accident well casing and the two magnetic sensors, respectively; solving the two sets of relationships yields the direction vector of the accident well relative to each of the magnetic sensors.

2. The method for directional measurement of accident wells based on spatial magnetic field information according to claim 1, characterized in that, Determining the rotation matrix from the probe coordinate system to the geomagnetic coordinate system based on the magnetic field information and the acceleration data includes: The angles between the three axes of the probe coordinate system and the corresponding three axes of the geomagnetic coordinate system are calculated using the detection component value of any of the magnetic sensors and the gravitational acceleration component obtained by the accelerometer. For each included angle, a sub-matrix corresponding to the rotation process around the axis is constructed, and then combined to obtain the rotation matrix.

3. The method for directional measurement of accident wells based on spatial magnetic field information according to claim 1 or 2, characterized in that, The step of converting the direction vector into corresponding angle information includes: Using true north as a reference point, the tangent function is used in conjunction with the magnetic declination data of the measurement location to calculate the radian information in the magnetic north direction, and finally the direction vector is converted into the angle information.

4. The method for directional measurement of accident wells based on spatial magnetic field information according to claim 1, characterized in that, The accident well orientation measurement system also includes a data transmission module and a host computer. The data transmission module is used to transmit the detected magnetic field information and acceleration data to the host computer. The host computer is used to analyze the magnetic field information and acceleration data to calculate the azimuth information of the accident well.

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