High-precision well deviation and azimuth measurement method based on multi-axis sensor

Abstract

The invention discloses a high-precision well deviation and azimuth measurement method based on a multi-axis sensor, and the method comprises the steps: 1, building a local navigation coordinate system of an underground environment in consideration of the influence of the earth curvature and the earth rotation, and obtaining a reconstruction signal; 2, based on the sensor mass of the four-axis sensor, considering the Coriolis force influence caused by earth rotation, and calculating a Coriolis force compensation vector; 3, calculating the projection of the geomagnetic field in the local navigation coordinate system to obtain a geomagnetic field projection vector; and 4, according to the gravity compensation value, the Coriolis force compensation vector and the geomagnetic field projection vector, in combination with the reconstruction signal, calculating a corrected hole drift angle and a corrected azimuth angle. According to the invention, the precision of well deviation and azimuth measurement is obviously improved.

Description

Technical Field

[0001] The invention relates to the field of measurement technology, and in particular to a high-precision well inclination and azimuth measurement method based on a multi-axis sensor. Background Art

[0002] Accurate measurement of well inclination and azimuth is a crucial technical link in oil and gas drilling, mineral mining and geological engineering. In the complex underground environment, accurate acquisition of the wellbore's spatial posture information (i.e., well inclination and azimuth) not only helps to ensure the stability and safety of the wellbore trajectory, but also directly affects the efficiency and cost of resource extraction. Although existing technologies have made certain progress in the field of well inclination and azimuth measurement, there are still many technical bottlenecks and application difficulties in deep wells, highly deviated wells and complex geological conditions, resulting in the accuracy and reliability of the measurement results being difficult to meet high-standard engineering requirements.

[0003] Inertial sensors (such as accelerometers and gyroscopes) are one of the basic devices for measuring well inclination and azimuth. Accelerometers calculate the well inclination angle by measuring the gravity acceleration component, while gyroscopes calculate the azimuth angle by integrating the angular velocity. Technology based on inertial sensors has the advantages of strong real-time performance and no need for external reference, and has become a common solution, especially in underground environments where radio signals cannot cover. However, inertial sensors have the following problems: the drift error of the gyroscope will accumulate over time, causing the measurement results to deviate from the true value. Especially in deep well operations, this accumulated drift may reach a level that cannot be ignored. Accelerometers are susceptible to dynamic interference under vibration, impact or rapid movement, resulting in measurement deviations in the direction of gravity, thereby affecting the calculation accuracy of the well inclination angle. In deep or highly deviated wells, due to the influence of the earth's curvature and changes in the geomagnetic field, measurement methods that rely solely on inertial sensors are often difficult to accurately reflect the true posture of the wellbore.

[0004] The magnetometer measures the direction and strength of the geomagnetic field to infer the azimuth of the wellbore. This method is relatively simple and has low requirements for power consumption and volume. However, the magnetometer is affected by the following factors in the underground environment: Due to the complexity of geological conditions (such as iron ore layers, metal pipes, etc.), the geomagnetic field may be significantly abnormal locally, causing the magnetometer measurement value to deviate from the true value. In the case of rapid rotation or vibration of the sensor, the direction measurement of the magnetometer is easily interfered by errors, resulting in unstable azimuth solution results. The strength of the geomagnetic field varies with depth and latitude, and the existing technology has not fully considered the impact of these factors on measurement accuracy. Summary of the invention

[0005] The purpose of the present invention is to provide a high-precision well inclination and azimuth measurement method based on a multi-axis sensor, which integrates the data of an accelerometer, a gyroscope, a magnetometer and a speedometer, and realizes high-precision attitude measurement in a complex underground environment by constructing a local navigation coordinate system, signal reconstruction, Coriolis force compensation, geomagnetic field projection correction and gravity anomaly compensation. The present invention significantly improves the accuracy of well inclination and azimuth measurement, effectively solves the error problems caused by the earth's curvature, rotation effect, geomagnetic field anomaly and gravity field change in traditional methods, and provides reliable guarantee for high-precision measurement in deep wells, high-angle wells and complex geological conditions.

[0006] In order to solve the above technical problems, the present invention provides a high-precision well inclination and azimuth measurement method based on a multi-axis sensor, the method comprising: Step 1: Considering the influence of the earth's curvature and rotation, a local navigation coordinate system of the underground environment is established; in the local navigation coordinate system, the measurement signal of the four-axis sensor is reconstructed to obtain a reconstructed signal; Step 2: Based on the sensor quality of the four-axis sensor, the three-dimensional velocity components measured by the four-axis sensor and the geographic coordinate position of the four-axis sensor, the Coriolis force compensation vector is calculated by considering the influence of the Coriolis force caused by the rotation of the earth; Step 3: Calculate the projection of the geomagnetic field in the local navigation coordinate system to obtain the geomagnetic field projection vector; consider the influence of gravity, combine the geological density and bottom density in the downhole environment, and calculate the gravity compensation value; Step 4: Calculate the corrected well inclination and azimuth according to the gravity compensation value, Coriolis force compensation vector and geomagnetic field projection vector in combination with the reconstructed signal.

[0007] Furthermore, the four-axis sensor includes: a gyroscope, a magnetometer, a three-axis speedometer and a three-axis accelerometer.

[0008] Furthermore, the local navigation coordinate system in step 1 Use the following formula to express it: ; in, is the average radius of the earth, which is 6371 km; is the height from the earth's center to the downhole measuring point where the four-axis sensor is located; is the geographical latitude of the downhole measuring point where the four-axis sensor is located; is the geographical longitude of the downhole measuring point where the four-axis sensor is located; is the angular velocity of the Earth’s rotation, and its value is , the unit is rad / s; is the speed of light; is the eccentricity of the Earth, and its value is 0.0818191908426.

[0009] Furthermore, in step 1, the measurement signal of the four-axis sensor is reconstructed in the local navigation coordinate system by the following formula to obtain the reconstructed signal : ; in, is the X-axis acceleration component of the three-axis accelerometer; is the Y-axis acceleration component of the three-axis accelerometer; is the Z-axis acceleration component of the three-axis accelerometer; is the X-axis angular velocity component of the gyroscope; is the Y-axis angular velocity component of the gyroscope; is the initial well inclination angle, ; is the Earth's gravitational constant; is the geomagnetic field strength of the magnetometer; is the initial direction angle, ; is the X-axis geomagnetic field intensity component of the magnetometer; is the Y-axis geomagnetic field intensity component of the magnetometer; Represents the modulus length operation of a vector; is the standard strength of the Earth's magnetic field, with a value of 49.6 and a unit of microtesla; is the atmospheric scale height, which is 7.4 km.

[0010] Furthermore, in step 2, the Coriolis force compensation vector is calculated by the following formula: : ; in, is the mass of the four-axis sensor; is the X-axis velocity component of the three-axis speedometer; is the Y-axis velocity component of the three-axis speedometer; is the Z-axis velocity component of the three-axis speedometer.

[0011] Furthermore, in step 3, the projection of the geomagnetic field in the local navigation coordinate system is calculated by the following formula: : ; in, is the geomagnetic inclination; is the magnetic declination; is the geomagnetic field attenuation coefficient, which is 640; is the temperature coefficient, and its value is 0.0033; is the current temperature; The standard temperature is 20 degrees Celsius.

[0012] Furthermore, in step 3, the gravity compensation value is calculated by the following formula: : ; in, is the earth shape factor, and its value is 0.00108263; is an integer subscript index with an upper limit of 4, which simplifies the continuous density distribution of the strata into a 4-layer model, representing the crust, mantle, outer core and inner core respectively; For the The geological average density of the bottom layer is the set value; is the standard formation density, with a value of 2.67 and a unit of .

[0013] Furthermore, in step 3, the corrected well inclination angle is calculated by the following formula: ; in, To correct the well inclination.

[0014] Furthermore, in step 3, the corrected azimuth is calculated by the following formula: ; in, To correct the azimuth.

[0015] The high-precision well inclination and azimuth measurement method based on a multi-axis sensor of the present invention has the following beneficial effects: The present invention significantly improves the accuracy of well inclination and azimuth measurement. Traditional measurement methods usually rely on a single sensor, such as an accelerometer or a magnetometer. Although this method is simple, it is difficult to ensure sufficient accuracy in a complex downhole environment. Downhole operations are affected by multiple factors such as the rotation of the earth, anomalies in the geomagnetic field, and changes in the distribution of the gravity field. The existing technology has not fully solved these problems, resulting in the accumulation of errors in the measurement results. The present invention fundamentally improves the measurement accuracy by adopting multi-axis sensor fusion technology, including accelerometers, gyroscopes, magnetometers, and speedometers, and combining signal reconstruction of multidimensional data, earth curvature correction, gravity anomaly compensation, and geomagnetic field projection correction. For example, the data fusion of the gyroscope and the accelerometer can dynamically adjust the drift error in the attitude measurement, and the data linkage of the magnetometer and the speedometer makes the azimuth angle solution more consistent with the real geomagnetic field direction. Combining the dynamic correction of each sensor data and the optimization of the physical model, the present invention can provide more stable and reliable well inclination and azimuth data under complex working conditions such as deep wells and high-angle wells.

[0016] Secondly, the present invention has demonstrated superior adaptability in a variety of complex geological and dynamic environments. The underground environment is complex and changeable, and the interference of different latitudes, depths and geological structures on the measurement varies significantly. Traditional methods are difficult to adapt to such dynamic changes in real time, and measurement errors accumulate, which may eventually lead to inaccurate wellbore trajectory control. The present invention constructs a local navigation coordinate system to uniformly map the earth's curvature, rotation effect and geomagnetic field distribution into the same reference system, thereby ensuring that the data collected by the sensor has a unified reference standard at any geographical location, well depth or inclination.

[0017] In addition, the present invention introduces a dynamic compensation mechanism, which can quickly adjust the measurement results when environmental parameters fluctuate by modeling and correcting the real-time changes of the gravity field and the geomagnetic field. For example, in areas with geomagnetic field anomalies or high-latitude areas, the present invention can avoid the interference of magnetic field anomalies on azimuth measurement by dynamically correcting the strength and direction of the geomagnetic field. For another example, under deep well conditions, due to the gravity field anomaly caused by changes in crustal density, the present invention significantly reduces the impact of gravity anomalies on well inclination calculations through the application of the formation density layering model. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0019] Figure 1 A schematic diagram of a method flow of a high-precision well inclination and azimuth measurement method based on a multi-axis sensor provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example 1, reference Figure 1 :A high-precision well inclination and azimuth measurement method based on a multi-axis sensor, the method comprising: Step 1: Considering the influence of the earth's curvature and rotation, a local navigation coordinate system of the underground environment is established; in the local navigation coordinate system, the measurement signal of the four-axis sensor is reconstructed to obtain a reconstructed signal; The core of step 1 is to consider the influence of the curvature and rotation of the earth on the measurement accuracy, construct a local navigation coordinate system suitable for the complex environment of the well, and reconstruct the measurement signal of the four-axis sensor in this coordinate system. The four-axis sensor includes a gyroscope, a magnetometer, a speedometer and a three-axis accelerometer, which work together to fully capture the dynamic changes and spatial characteristics of the well environment. In order to ensure the high accuracy of well inclination and azimuth measurement, it is necessary to fully combine the physical properties of the earth with the sensor signal processing technology, establish a coordinate reference adapted to the well environment and correct the errors in the sensor data. The construction of the local navigation coordinate system is the basis of this step. The ellipsoidal shape of the earth, the centrifugal force caused by the rotation of the earth, and the geological distribution characteristics of the well make the sensor susceptible to interference from errors when collecting data. In order to eliminate these interferences, the present invention first starts from the reference system of the earth and maps its position to the local navigation coordinate system according to the geographical location of the sensor (including longitude, latitude and depth). The construction process of this coordinate system fully considers the geometric shape changes caused by the curvature of the earth and the influence of the earth's rotation on the inertial force. These factors are corrected through mathematical models to ensure that the final constructed coordinate system can truly reflect the physical state of the underground environment. In this coordinate system, a clear reference direction is set: the X axis is east, the Y axis is north, and the Z axis is vertically upward (the opposite direction of the gravity direction) to ensure that the subsequent signal processing and measurement results have a unified reference standard. After the local navigation coordinate system is constructed, the present invention reconstructs the signal of the four-axis sensor. The gyroscope is responsible for measuring the angular velocity of the sensor in three-dimensional space, providing key data for the dynamic attitude change of the sensor; the magnetometer measures the direction and intensity of the geomagnetic field, which is an important basis for calculating the azimuth; the speedometer captures the motion velocity component of the sensor in three-dimensional space, providing basic information for describing dynamic motion; the three-axis accelerometer measures the gravity acceleration and linear acceleration components, which are used to calculate the inclination angle and gravity direction. However, the measurement data of a single sensor is often affected by environmental vibration, noise and dynamic changes, and directly using the original signal may lead to significant errors. Therefore, the present invention fuses the data of the four-axis sensor together by means of signal reconstruction to improve the reliability and accuracy of the signal. The key to signal reconstruction is to unify the measurement data of all sensors into the local navigation coordinate system, and process the correlation between different data components through a mathematical model. First, the data of the three-axis accelerometer and speedometer are used to identify the dynamic motion state of the sensor, and combined with the angular velocity data of the gyroscope, the non-inertial component caused by the acceleration is compensated to obtain accurate gravity direction information. At the same time, the data of the magnetometer is used to correct the attitude direction of the sensor to eliminate the influence of changes in the geomagnetic field at different latitudes and geological conditions. Through these processing steps, the reconstructed signal can comprehensively reflect the physical state of the downhole environment, such as the true acceleration direction, gravity direction and geomagnetic field direction.In the process of signal reconstruction, the present invention also makes full use of the complementary characteristics of multi-sensor data. For example, the gyroscope can capture the dynamic rotation changes of the sensor, but its measurement value is prone to drift over a long period of time, and the geomagnetic field direction information provided by the magnetometer can correct this drift, thereby ensuring the accuracy of azimuth calculation. On the other hand, the gravity component measured by the three-axis accelerometer may be affected by vibration or abnormal geological density downhole. At this time, the dynamic data of the velocimeter can provide additional correction basis. Through the mutual complementation and fusion of these multi-sensor data, the reconstructed signal not only eliminates the shortcomings of single sensor measurement, but also enhances the robustness and accuracy of the overall measurement.

[0022] Step 2: Based on the sensor quality of the four-axis sensor, the three-dimensional velocity components measured by the four-axis sensor and the geographic coordinate position of the four-axis sensor, the Coriolis force compensation vector is calculated by considering the influence of the Coriolis force caused by the rotation of the earth; Due to the particularity of the underground environment, the measurement system is not only affected by the complex geological conditions underground, but also needs to deal with the inertial force interference exerted by the rotation of the earth on the moving object. Coriolis force is a pseudo force caused by the rotation of the earth. Its essence is the inertial effect produced by the interaction between the rotation of the earth and the relative motion of the object. The influence of this force on the surface of the earth changes with the change of geographical location and the speed of the object. Especially in underground operations, since the equipment and sensors are in a small and confined space, the effect of Coriolis force may significantly change the speed and direction information measured by the sensor, resulting in deviations in the measurement of well inclination and azimuth. Therefore, effective compensation for Coriolis force is the key to ensuring the accuracy of the measurement results. The calculation of Coriolis force needs to combine multiple dynamic factors, including the mass, speed and geographical location of the four-axis sensor itself. First, the mass of the sensor determines the size of the Coriolis force, because according to the principle of physics, force is proportional to mass. In the present invention, the mass of the sensor is known, and by combining its real-time measured velocity component, the Coriolis force on the sensor in the inertial system of the earth's rotation can be derived. The three-dimensional components of velocity are measured by the velocimeter, including horizontal and vertical components along the downhole channel. These components not only describe the motion state of the sensor, but also have a clear physical relationship with the angular velocity of the Earth's rotation. The angular velocity of the Earth's rotation is a known constant, but its contribution to the Coriolis force varies at different geographic latitudes because objects on the Earth's surface experience different linear velocities of rotation with latitude. Especially in the downhole environment, the increase in depth may also have an indirect effect on the distribution of velocity components, so the specific location downhole (i.e., longitude, latitude, and depth) needs to be further combined to fully consider the effects of the Coriolis force.

[0023] When calculating the Coriolis force compensation vector, the present invention converts the earth's rotation effect into a vector form that can be directly analyzed and compensated by establishing a local navigation coordinate system. In this way, the direction and magnitude of the Coriolis force can be clearly described in the local coordinate system. Specifically, the direction of the Coriolis force is closely related to the velocity component of the object and the relationship between the earth's rotation axis. In the local navigation coordinate system, the earth's rotation axis is usually decomposed into components with the local horizontal plane and vertical direction. In this way, the Coriolis force vector components in various directions under the influence of the earth's rotation can be calculated through the speed data provided by the speedometer. This calculation method can ensure the adaptability of the compensation process in a dynamic environment, and the compensation vector can be adjusted in time regardless of whether the sensor is in an acceleration, deceleration or stable motion state. The introduction of the compensation vector is to solve the interference of the Coriolis force on the measurement results of the four-axis sensor. Without compensation, the Coriolis force may cause systematic errors in the velocity measurement of the sensor, thereby affecting the calculation of the well inclination and azimuth. For example, if a sensor moves at high speed along an underground channel, the Coriolis force caused by the rotation of the earth will cause its measurement results to be offset, and this offset cannot be corrected by simple static calibration. The present invention can not only eliminate this dynamic error by introducing a compensation vector, but also ensure the reliability of the sensor in a complex environment. The Coriolis force compensation vector is a dynamic adjustment process, and its size and direction will be updated in real time as the sensor's motion state changes. This dynamic adjustment depends on the real-time acquisition of sensor data and the accuracy of the local navigation coordinate system, ensuring the effectiveness and real-time nature of the compensation. In addition, the implementation of Coriolis force compensation also involves the isolation of other interfering factors. For example, gravity anomalies caused by geological conditions may have additional effects on the speed and direction measurements of the sensor, which requires combining with gravity compensation to ensure the independence and accuracy of Coriolis force compensation. At the same time, changes in the directionality and intensity of the geomagnetic field may also interfere with the compensation process, so the present invention further corrects the direction of the Coriolis force compensation vector through the data of the magnetometer to make it more consistent with the actual environment.

[0024] Step 3: Calculate the projection of the geomagnetic field in the local navigation coordinate system to obtain the geomagnetic field projection vector; consider the influence of gravity, combine the geological density and bottom density in the downhole environment, and calculate the gravity compensation value; This process calculates the projection vector of the geomagnetic field in the local navigation coordinate system, and calculates the gravity compensation value in combination with the geological density and bottom density of the underground environment, thereby providing a more accurate physical basis for the subsequent calculation of the well inclination and azimuth. The geomagnetic field and the gravity field are two key factors affecting the accuracy of well inclination and azimuth measurement. Their distribution is not only related to the natural characteristics of the earth, but also significantly affected by the special environment of the underground. Therefore, the projection and compensation of the geomagnetic field and the gravity field are necessary means to ensure the high accuracy of the measurement results. First of all, the distribution and projection of the geomagnetic field are a key point of this step. On the surface of the earth, the geomagnetic field can be regarded as a vector field, and its direction and intensity vary depending on the geographical location. The geomagnetic field in the underground environment is not only affected by the magnetic field of the earth's core, but may also be disturbed by the local geological structure. Therefore, in order to ensure the accuracy of the measurement, the present invention uses a magnetometer in a four-axis sensor to collect the component data of the geomagnetic field in real time. These component data include the three-directional projections of the geomagnetic field in space, and the vector direction of the geomagnetic field can be accurately determined by these data. In the local navigation coordinate system, the vector of the geomagnetic field is decomposed into horizontal and vertical components. This decomposition can more clearly describe the contribution of the geomagnetic field to the orientation measurement. For example, the horizontal component of the geomagnetic field is mainly used to determine the azimuth of the sensor, while the vertical component is related to the measurement of the well inclination.

[0025] The calculation of the geomagnetic field projection vector not only depends on the data of the magnetometer, but also needs to be combined with the reference direction in the local navigation coordinate system. In the present invention, a corrected geomagnetic field vector is obtained by defining the standard direction of the geomagnetic field in the navigation coordinate system (i.e., the geomagnetic field direction in an ideal situation) and projecting the measured actual geomagnetic field vector onto this standard direction. This correction process takes into account the disturbance effect of the local geomagnetic field, such as the distortion of the geomagnetic field caused by underground geological anomalies or interference from metal structures. The accuracy of azimuth calculation can be significantly improved by the corrected geomagnetic field projection vector. On the other hand, the compensation of the gravity field is another core content of this step. The gravity field in the underground environment is affected by many factors, including the gravity distribution characteristics of the earth and the changes in local geological density. The gravity distribution of the earth is not completely uniform, but is jointly affected by the shape of the earth, geological layers, and differences in crustal density. In the present invention, the accelerometer and gravimeter in the four-axis sensor are used to measure the intensity and direction of the gravity field in real time. However, these measurement results may be biased due to changes in underground geological density, so it is necessary to accurately compensate the gravity field. In order to calculate the gravity compensation value, the present invention combines the geological density and bottom density information of the downhole environment. The geological density is a physical parameter that describes the density of materials in different geological layers, while the bottom density is used to represent the density distribution characteristics of deeper layers in the well. These density parameters are usually obtained through downhole geological surveys or historical data and are used as the basis for gravity compensation calculations. In the compensation calculation, the distribution of geological density is processed in layers, and the contribution of the density of each layer to the total gravity field is calculated by weighted accumulation. This calculation method fully considers the density differences of different geological layers and their local effects on the gravity field, thereby accurately describing the actual distribution of the gravity field in the well. The calculation of the gravity compensation value is ultimately used to correct the gravity direction and intensity measured by the sensor. Without compensation, gravity anomalies may cause deviations in the well inclination angle measurement results, especially in areas with large differences in crustal density, and this deviation may accumulate into significant measurement errors. By introducing the gravity compensation value, the present invention can effectively eliminate this error and ensure that the measurement results are closer to the actual physical state of the well.

[0026] Step 4: Calculate the corrected well inclination and azimuth according to the gravity compensation value, Coriolis force compensation vector and geomagnetic field projection vector in combination with the reconstructed signal.

[0027] Specifically, the calculation of the well inclination and azimuth needs to rely on the data of multi-axis sensors. After the processing of the previous steps, most of the interference caused by the rotation of the earth, the curvature of the earth, the local geomagnetic anomaly and the gravity anomaly has been removed. However, even after compensation, the original signal of the sensor still contains certain nonlinear errors. Especially in the case of dynamic motion, the data inconsistency between sensors will lead to unstable measurement results. Therefore, the present invention introduces a correction algorithm based on multi-axis fusion in step 4, and takes the gravity compensation value, the Coriolis force compensation vector and the geomagnetic field projection vector as key correction factors, and fuses them with the signal reconstruction results to ensure that the calculation process of the well inclination and azimuth can reflect the dynamic changes of the downhole environment in real time. First, the calculation of the well inclination is based on the direction of gravity. The well inclination is the angle between the sensor axis and the direction of gravity, so the data of the accelerometer and the gravimeter play a core role in this process. The sensor data after signal reconstruction provides a corrected three-dimensional acceleration vector, which has eliminated the influence of dynamic acceleration and environmental noise. On this basis, the gravity compensation value is used to further correct the interference of the downhole gravity anomaly on the measurement results. By performing an inner product operation on the reconstructed acceleration vector and the corrected gravity direction vector, the cosine value of the well inclination angle can be accurately calculated, thereby deriving the well inclination angle. It is worth noting that due to the dynamic nature of the downhole environment, the calculation of the well inclination angle requires real-time adjustment of the sensor's attitude parameters to adapt to external disturbances that change over time. Therefore, the Coriolis force compensation vector is introduced at this stage to correct the inertial interference caused by the earth's rotation. Although this interference is weak on the surface, it will be amplified when the depth is large underground. Therefore, the compensation process is a necessary means to ensure the accuracy of the well inclination angle. The calculation of the azimuth angle is based on the geomagnetic field. The horizontal component of the geomagnetic field is the main reference direction of the azimuth angle, and the geomagnetic field vector measured by the magnetometer is projected into horizontal and vertical components in the local navigation coordinate system. After the compensation in the previous steps, the direction information of the geomagnetic field has been corrected, but to achieve high-precision azimuth angle calculation, it is also necessary to fuse the geomagnetic field vector with other sensor data. In the present invention, the horizontal projection direction of the geomagnetic field is defined as the reference direction, and the angle between the actual geomagnetic field vector measured by the magnetometer and the reference direction is the azimuth. In order to further improve the accuracy, the Coriolis force compensation vector and the signal reconstruction data play a role here again. The Coriolis force compensation vector is used to correct the magnetic field direction offset caused by the inertial change of the sensor during dynamic motion, while the signal reconstruction data provides a dynamically consistent reference frame to ensure that the data fusion between the magnetometer and other sensors is consistent.

[0028] Embodiment 2: The four-axis sensor includes: a gyroscope, a magnetometer, a three-axis speedometer and a three-axis accelerometer.

[0029] Specifically, the gyroscope is one of the core components in the four-axis sensor system, which is responsible for measuring the angular velocity change of the sensor in three-dimensional space. Since the downhole equipment often rotates or deflects under complex geological conditions, the gyroscope can provide dynamic attitude information by capturing the angular velocity in real time. This data is crucial to the calculation of the well inclination and azimuth, because the angular velocity can reflect the rotation state of the sensor relative to the reference direction. In the present invention, the data of the gyroscope and the data of the magnetometer work together to correct the attitude drift problem in a dynamic environment. By fusing the angular velocity data of the gyroscope, the system can dynamically adjust the attitude calculation model so that the measurement results remain highly accurate in the complex downhole environment. As another important component of the four-axis sensor, the magnetometer is mainly used to measure the direction and intensity of the geomagnetic field. This data is the basis for azimuth calculation, because the projection of the geomagnetic field on the horizontal plane directly indicates the direction of the sensor relative to the geomagnetic north. However, the geomagnetic field is not uniformly distributed, especially in the downhole environment, it may be disturbed by geological structures or metal materials, resulting in magnetic field anomalies. The present invention collects data through a magnetometer, and combines signal reconstruction and compensation algorithms to correct these anomalies, so that the measured value of the geomagnetic field is closer to the true value. In addition, the magnetometer data is combined with the angular velocity data of the gyroscope to resolve directional errors that may occur in the sensor during dynamic motion, thereby significantly improving the calculation accuracy of the azimuth angle.

[0030] The three-axis velocity meter is a component in the four-axis sensor responsible for measuring the linear velocity component. It can capture the movement speed of the sensor in the three-dimensional space of the well in real time, including the horizontal component and the vertical component along the well channel. These velocity data are not only used to describe the motion state of the sensor, but also play a key role in the Coriolis force compensation. Since the rotation of the earth will exert Coriolis force on the moving object, the interaction between the velocity component and the angular velocity of the earth's rotation will significantly affect the measurement accuracy. In the present invention, the real-time velocity data provided by the three-axis velocity meter is used to calculate the Coriolis force compensation vector, thereby eliminating the interference of the earth's rotation on the calculation of the well inclination and azimuth. In addition, the data of the velocity meter is combined with the data of the accelerometer to detect the acceleration or deceleration state of the sensor, thereby providing richer information for dynamic correction. The three-axis accelerometer is a component used to measure the linear acceleration and gravity acceleration of the sensor. In the downhole environment, the data of the accelerometer is the core input for the calculation of the well inclination, because the direction of the gravity acceleration defines the direction of the reference gravity field. By measuring the three-dimensional acceleration components, the accelerometer can determine the angle between the sensor and the gravity direction, and then derive the well inclination. However, the accelerometer may be disturbed by linear acceleration and environmental vibration in dynamic motion, which may cause errors in the measurement of gravity direction. The present invention introduces signal reconstruction and compensation algorithms to fuse the data of the accelerometer with the data of the gravimeter and the speedometer, thereby eliminating the influence of dynamic acceleration. In addition, the data of the accelerometer can also be used in conjunction with the data of the gyroscope and the magnetometer to further correct the attitude drift problem of the sensor, making the calculation result of the well inclination angle more stable and reliable.

[0031] Example 3: Local navigation coordinate system in step 1 Use the following formula to express it: ; in, is the average radius of the earth, which is 6371 km; is the height from the earth's center to the downhole measuring point where the four-axis sensor is located; is the geographical latitude of the downhole measuring point where the four-axis sensor is located; is the geographical longitude of the downhole measuring point where the four-axis sensor is located; is the angular velocity of the Earth’s rotation, and its value is , the unit is rad / s; is the speed of light; is the eccentricity of the Earth, and its value is 0.0818191908426.

[0032] Specifically, in practical applications, underground measuring points are often located hundreds or even thousands of meters below the surface. This parameter usually appears in the form of negative values, but its physical meaning is still the outward (or inward) distance from the center of the earth to the location of the sensor. The depth of the wellbore is 6371 km. If the depth of several thousand or hundreds of meters from the surface to the wellbore is ignored, the traditional method will not take into account the small curvature deviation. However, for the high-precision well inclination and azimuth measurement pursued by the present invention, even a change of several kilometers may accumulate non-negligible coordinate offset. and After determination, the position vector formed by these three-dimensional components can not only reflect the real space coordinates of the sensor in the east-west, north-south and vertical directions, but also To correct the difference between the polar radius and the equatorial radius, it is more consistent with the actual geometry of the earth. This means that when performing downhole measurements in high or low latitudes, the coordinate deviation obtained can be reduced to a very low level, which is significantly better than the traditional approach of simply treating the earth as a regular sphere. The angular velocity of the Earth's rotation is the same as the speed of the Earth's rotation. Although the value is not large, the centrifugal force accumulated during long-term measurement activities will affect the positioning accuracy in all directions, especially in scenarios where downhole sensors need to maintain high posture stability or move long distances in the wellbore. This exponential correction can be understood as a fine-tuning at the "relative" level: under strict accuracy requirements, using Reflecting the latitude difference, the centrifugal force correction at different latitudes is no longer simply unified, but varies with the latitude; at the same time, it introduces The factor of is used to characterize the effect of the speed of light, thus ensuring that even tiny drifts can be identified and compensated in a timely manner. Compared with systems that only consider relativistic factors in high-precision satellite navigation or astrometry, the present invention brings such corrections into the field of downhole measurement earlier, greatly improving the adaptability of the coordinate system to the real rotation environment, thereby reducing the additional correction steps required in the subsequent calculation of well inclination and azimuth.

[0033] From another perspective, the construction of this local navigation coordinate system also corresponds to the data fusion strategy of multi-axis sensors. Since the four-axis sensor includes a gyroscope, a magnetometer, a three-axis speedometer, and a three-axis accelerometer, the data collected by each sensor underground needs to be projected into the same reference system for fusion and compensation. If such a coordinate framework that fully considers the geophysical characteristics is not established first, then the subsequent Coriolis force compensation, geomagnetic field projection, and gravity field anomaly correction may lack a unified alignment benchmark. It is precisely because of this that , , , and Only by incorporating key earth parameters such as the position vector into the expression method, the present invention can compensate for the errors caused by these parameters in a hierarchical and phased manner in the subsequent steps. For example, the Coriolis force compensation will be more obvious in higher latitudes. If it is not considered in advance in the coordinate system Even if the compensation algorithm itself is sophisticated, it cannot fundamentally avoid the system deviation caused by improper selection of coordinate system. This part specifically reflects the degree of contraction of the earth in the pole direction, so that when the sensor is close to the pole or is more north (south) relative to the equator, the difference in longitudinal radius can be fully incorporated into the calculation formula of the position vector. For well inclination and azimuth measurement, longitudinal error often directly affects the assessment of well inclination angle or relative formation distribution. If the influence of the earth's eccentricity is ignored, it is particularly easy to cause inaccurate inclination azimuth estimation in deep well scenarios. The formula of the present invention is written in explicit form as and This combination is designed to take into account the Earth's ellipsoidal parameters in both horizontal and vertical directions, thereby providing relatively consistent measurement accuracy in various geographical environments between the poles and the equator.

[0034] Embodiment 4: In step 1, the measurement signal of the four-axis sensor is reconstructed in the local navigation coordinate system by the following formula to obtain the reconstructed signal : ; in, is the X-axis acceleration component of the three-axis accelerometer; is the Y-axis acceleration component of the three-axis accelerometer; is the Z-axis acceleration component of the three-axis accelerometer; is the X-axis angular velocity component of the gyroscope; is the Y-axis angular velocity component of the gyroscope; is the initial well inclination angle, ; is the Earth's gravitational constant; is the geomagnetic field strength of the magnetometer; is the initial direction angle, ; is the X-axis geomagnetic field intensity component of the magnetometer; is the Y-axis geomagnetic field intensity component of the magnetometer; Represents the modulus length operation of a vector; is the standard strength of the Earth's magnetic field, with a value of 49.6 and a unit of microtesla; is the atmospheric scale height, which is 7.4 km.

[0035] Specifically, in this formula, Represent the acceleration components of the three-axis accelerometer respectively. These acceleration data contain both the linear acceleration of the sensor in dynamic motion and the information of the gravity direction. However, since the underground environment is often accompanied by complex geological and mechanical vibrations, if only relying on the accelerometer data itself to estimate the well inclination, there will be significant errors. Multiply and will Multiply The angular velocity components of the accelerometer and gyroscope are The coupling enables the sensor to rely on the gyroscope data to correct the real-time changes of the accelerometer when it rotates rapidly or changes suddenly. When the sensor tends to be stable, the gravity information provided by the accelerometer can be used to correct the accumulated drift of the gyroscope. is defined as the initial well inclination angle, which is given by This means that when the sensor is first placed or recalibrated, the angle between the static acceleration component and the vertical line of the ground can be obtained, thereby providing a reference value for subsequent dynamic compensation. Similarly, the initial direction angle in azimuth can be This is also due to the measurement of the projection component of the geomagnetic field on the horizontal plane by the magnetometer, and the coordinate unification is performed through the local navigation coordinate system constructed in the previous step of the present invention, thus avoiding the problem of inconsistent coordinates in the three-dimensional space posture transformation of the device.

[0036] At the same time, the formula This reflects the idea of ​​combining the earth's gravitational constant with the radius of the current measuring point. This allows the slight changes in gravity to be taken into account when the sensor is at different depths or longitudes and latitudes, which is of great significance for well inclination measurements with extremely high precision requirements. The introduction of this item may result in non-negligible measurement deviations in deep well operations or under extreme geological conditions. This coupled relationship between gravity and position is further projected onto the unit direction vector, so that the gravity vector and the position vector are understood and used on the same reference scale, leaving room for the scale adjustment and compensation factor behind the formula. It is worth noting that The role of this ratio in the formula is to convert the local geomagnetic field strength measured by the sensor into The standard intensity of geomagnetic field By comparing the possible regional anomalies of the geomagnetic field or the magnetic field differences in different regions around the world, the sensor data can be relatively uniformly quantitatively corrected in both weak and strong geomagnetic areas. Since the geomagnetic field may be disturbed by rock or metal materials both on the surface and underground, this normalization is of great value for azimuth correction. If it is not normalized, it will often cause systematic deviations in azimuth calculations. This exponential decay factor is calculated from the atmospheric scale height. From the perspective of, it simulates the field strength attenuation characteristics caused by changes in depth or height. When the sensor is far away from the surface, various atmospheric or near-surface effects will gradually weaken. For example, the impact of electromagnetic wave refraction and temperature gradient changes on the equipment will also change accordingly. With the help of this attenuation factor, these interferences can be approximated at the mathematical level, so that the reconstructed signal is closer to the actual downhole conditions and the measurement fluctuations caused by changes in environmental parameters are reduced. It is precisely because this formula internally couples the accelerometer, gyroscope and geomagnetic field data one by one and superimposes multiple corrections of gravity constant and environmental attenuation that the final result is It becomes a comprehensive reconstructed signal, laying a key digital foundation for the high-precision well inclination and azimuth measurement of the present invention. In the subsequent steps, when the system needs to calculate the well inclination and azimuth, it can directly use Combined with other compensation items (such as Coriolis force compensation, magnetic field projection correction or geological density correction), the data processing process is greatly simplified and each sensor channel can be synchronously included in the same algorithm framework. In this way, any measurement error caused by the individual sensor will also be integrated into the In the process of drilling, the two sensors are offset or weakened, and finally achieve higher measurement accuracy than traditional single sensor or simple data splicing. Especially in deep wells, inclined wells or high temperature and high pressure wells, real-time acquisition of accurate well inclination and azimuth is of vital importance to drilling trajectory control.

[0037] Embodiment 5: In step 2, the Coriolis force compensation vector is calculated by the following formula: : ; in, is the mass of the four-axis sensor; is the X-axis velocity component of the three-axis speedometer; is the Y-axis velocity component of the three-axis speedometer; is the Z-axis velocity component of the three-axis speedometer.

[0038] Specifically, the rotation of the earth will exert an inertial force on the moving object, namely the Coriolis force. If it is not taken into account, it will often cause systematic deviations in the velocity and attitude calculation in the underground environment. To this end, the present invention obtains the velocity components of the sensor in the X, Y, and Z directions through a three-axis speedometer, and combines the sensor mass 、Earth's rotation angular velocity and the geographical location of the measuring points (including and ), the Coriolis force is vectorized and compensated according to the given formula. The most intuitive part of the formula is the previous The coefficient comes from the definition of Coriolis force in classical mechanics, that is, However, it is not enough to simply cross-product the Earth's rotational angular velocity with the velocity component, because in the underground environment, the latitude and longitude Will directly determine the projection direction and intensity of each component in the local coordinate system: near the equator, As it approaches 1, the centrifugal force component increases, and in high latitudes, The contribution will be more reflected.

[0039] The present invention is achieved by converting Respectively and Combined to ensure that the components of the three-dimensional velocity vector and the Earth's rotation are accurately described in all directions. At the same time, it also introduces This correction factor is not common in the traditional Coriolis force calculation formula. The reason for using this additional factor is mainly to compensate for the errors caused by the distribution of the earth's gravitational potential energy and the fine-tuning of the relativistic effect in deep well environments; when the sensor is located at different depths, The value of will change, so that the compensation factor will fluctuate slightly with depth, thus more truly reflecting the inertial correction of the earth's rotation system for different gravitational potential heights. In addition, the present invention uniformly maps all vector components to the previously established local navigation coordinate system, so that the Coriolis force can not only be accurately described in vector form in theory, but also be calculated and updated in real time through numerical means in engineering practice. When the sensor moves underground at a certain speed, the Coriolis force compensation vector It can be immediately calculated according to the formula, and then directly applied to the measurement model during signal reconstruction and attitude solution, eliminating the inertial interference caused by velocity changes. Especially in the scenario of deep wells or high-speed penetration of formations, if Coriolis force compensation is not performed, the velocity and acceleration data measured by the sensor will be mixed with some false components caused by the rotation of the earth, thereby affecting the subsequent solution accuracy of the well inclination and azimuth. The present invention distinguishes the velocity component in the formula The angular velocity of the Earth's rotation and longitude and latitude , The purpose is to remove the proportion of Coriolis force in the dynamic signal collected by the triaxial velocity meter and retain the actual movement information of the sensor in the formation. It is worth noting that although the angular velocity of the earth's rotation is not large, the influence of the Coriolis force will be amplified as the speed of downhole equipment increases; and in high latitudes or near polar regions, The term decays significantly. The contribution of the term to the formula is highlighted. The vector operation adopted by the present invention explicitly reflects these geographical factors, greatly improving adaptability and reliability.

[0040] Example 6: In step 3, the projection of the geomagnetic field in the local navigation coordinate system is calculated by the following formula: : ; in, is the geomagnetic inclination; is the magnetic declination; is the geomagnetic field attenuation coefficient, which is 640; is the temperature coefficient, and its value is 0.0033; is the current temperature; The standard temperature is 20 degrees Celsius.

[0041] Specifically, here and They are the geomagnetic inclination and the geomagnetic declination, which determine the angular distribution of magnetic lines of force in space. The declination is the angle between the Earth's magnetic field and the horizontal plane. It represents the degree of deviation between magnetic north and geographic north. , as well as , can perform basic decomposition of the geomagnetic field in three-dimensional coordinates, thereby obtaining the magnetic field components under ideal conditions. This component is usually measured or calculated in a ground reference system or a global geomagnetic model. If it is directly applied to the underground environment, it will produce non-negligible deviations, so it is necessary to make multiple corrections to it. Next, Used to describe the attenuation and variation of the Earth's magnetic field with depth or height. It can be regarded as a geomagnetic field attenuation coefficient, and its magnitude is related to the geomagnetic model. Because underground operations are usually hundreds or even thousands of meters below the crust, if the effect of well depth on magnetic field strength is ignored, significant errors may occur in azimuth measurement. (the height of the underground measuring point relative to the center of the earth, usually a negative value) to dynamically adjust the magnetic field strength, making the model closer to the real underground scene. As it continues to grow, There will be a certain degree of weakening or strengthening effect, which provides the necessary field strength correction for deep well measurement.

[0042] Later introduced This vector is the normalized form of the local navigation coordinate system vector established in the previous step. In the method system of the present invention, It not only records the curvature of the earth and the downhole longitude and latitude information, but also includes the correction factor of the earth's rotation. The purpose of multiplying it with the geomagnetic field is to reproject the geomagnetic vector in the same reference coordinate frame, so that the measurement results of the magnetometer are consistent with other physical quantities (such as the gravity field or Coriolis force). In other words, this step can be regarded as "aligning" the magnetic field information with the downhole coordinate system to avoid errors caused by improper conversion of data between different coordinates. As for This item is a linear correction for the subtle effect of temperature on the geomagnetic field. Since the temperature of the geomagnetic probe or magnetometer when operating underground is often much higher than the ground environment, and the magnetic susceptibility of magnetic materials is closely related to temperature, temperature changes in the equipment and the surrounding environment will cause changes in probe sensitivity and zero drift. If this is ignored, especially when the well temperature changes drastically or the measuring point is deep, the original magnetic measurement data may have a systematic offset. Here is the temperature coefficient, which is given as 0.0033 in this embodiment, meaning that when the temperature deviates from the standard temperature hour, and After multiplication, the effective amplitude of the geomagnetic field will be corrected. Although this correction based on the linear assumption simplifies the complex temperature-magnetic relationship, it can bring a fairly accurate compensation effect within the temperature range of most engineering applications, ensuring the effectiveness of the geomagnetic field projection vector.

[0043] Example 7: In step 3, the gravity compensation value is calculated by the following formula: : ; in, is the earth shape factor, and its value is 0.00108263; is an integer subscript index with an upper limit of 4, which simplifies the continuous density distribution of the strata into a 4-layer model, representing the crust, mantle, outer core and inner core respectively; For the The geological average density of the bottom layer is the set value; is the standard formation density, with a value of 2.67 and a unit of .

[0044] Specifically, the first part of the formula is the classic Newtonian gravity formula, which describes the gravitational force of the earth on an object, where is the gravitational constant, is the mass of the Earth, Represents the radial distance from the center of the earth to the measuring point. This term is the basis of the gravity distribution under the ideal spherical model of the earth, but because the actual shape of the earth is an oblate spheroid and the gravity values ​​at different latitudes are different, further corrections need to be introduced on this basis. Part II It is the correction term for the shape of the earth, which is used to compensate for the oblate spheroid effect of the earth, which is slightly bulging at the equator and slightly flattened at the poles due to its rotation. is a standardized value that quantifies the effect of the Earth's flattening on the distribution of the gravity field. In this correction term, Used to describe the influence of the latitude of the measuring point, the difference of the three items It reflects the geometric distribution characteristics of the earth's gravity changes in different latitudes. For example, in the equatorial region, Close to 1, resulting in a decrease in the correction term, indicating that the gravity value is small; while near the poles, As the value approaches 0, the correction term increases, reflecting the greater polar gravity. With this correction, the formula not only takes into account the effect of the Earth's shape, but also accurately reflects the difference in gravity at different latitudes, making the measurement results closer to reality.

[0045] The last part of the formula This is a correction of the density of geological layers inside the earth. Due to the huge differences in density distribution of the crust, mantle, outer core and inner core, the gravity value in underground operations is not only related to the overall mass of the earth, but also affected by the density of local strata. This invention simplifies the interior of the earth into a 4-layer model, with each layer having a density of The average density of the crust, mantle, outer core, and inner core, respectively. The advantage of this layered modeling is that it can explicitly quantify the contribution of different depth regions to the gravity field without the need for complex integral calculations of the continuous density distribution. It is a commonly used geological reference value, which is used as the normalized benchmark for relative density. In the layer correction, the contribution of each layer density is expressed as The form of joining, where It is a weighting factor used to describe the phenomenon that the cumulative effect of density gradually weakens in the depth direction. For example, the density change of the crust (layer 1) has a much greater impact on the gravity of the measuring point than the density change of the inner core (layer 4), because the inner core is farther away from the measuring point and its contribution is relatively smaller. By combining the earth shape correction with the geological density correction, the final calculated gravity compensation value is It can truly reflect the gravity distribution in the complex environment of the well. This result will be directly applied to the acceleration data processing of the sensor to eliminate the influence of gravity anomalies in dynamic measurements. For example, the calculation of the well inclination angle depends on the gravity direction measured by the accelerometer. If gravity compensation is not considered, the sensor may mistake the gravity deviation caused by local geological anomalies as attitude changes, thereby affecting the measurement accuracy. , the present invention can accurately correct these interferences, making the accelerometer data more reliable. In addition, the design of the geological density correction part fully reflects the present invention's consideration of the complexity of the strata. Although the density distribution inside the earth changes continuously, in actual engineering, continuous models are often difficult to achieve fast calculations. The present invention adopts a 4-layer hierarchical model to simplify complex geological characteristics into an operational calculation model while maintaining high sensitivity to major density change areas. Especially in deep well operations, the long-range effects of the outer core and inner core are reflected through the corrections of the third and fourth layers, while the close-range effects of the crust and mantle are fully described by the corrections of the first and second layers. This method achieves a good balance between computational complexity and accuracy, so that the formula can not only meet the needs of real-time calculations underground, but also ensure the accuracy of the measurement results.

[0046] Embodiment 8: In step 3, the corrected well inclination angle is calculated by the following formula: ; in, To correct the well inclination.

[0047] Specifically, the core part of the formula is , which describes the relationship between the calculation of well inclination and multiple physical quantities in the local navigation coordinate system. First, It is the dot product of the reconstructed signal and the projection vector of the geomagnetic field, which is used to measure the consistency of the directions of the two. It is the fusion result of sensor data, including the measurement values ​​of accelerometer, gyroscope, speedometer and magnetometer, and its direction can reflect the actual attitude of the sensor; and the geomagnetic field projection vector It provides a stable reference direction. The dot product result shows the angle between the actual attitude of the sensor and the direction of the geomagnetic field. This information is the basis for calculating the well inclination. It is not enough to fully reflect the complex influence of the underground environment, so the formula is further introduced . is the Coriolis force compensation vector, is the gravity compensation value, and the dot product of the two represents the interference component of the earth's rotation and gravity anomaly on the measurement results. This part is removed from the dot product Especially in high-speed motion or deep well environments, the Coriolis force has a significant impact on the dynamics of sensor measurements, while the gravity compensation value takes into account the changes in the gravity field caused by the shape of the earth and geological stratification. The comprehensive correction of the two can effectively improve the reliability of the measurement.

[0048] Denominator It is used to normalize the dot product results to ensure that the output of the formula is always within a reasonable value range (i.e. ). The modulus of the reconstructed signal and the geomagnetic field projection vector respectively represents their intensity. Through normalization operation, the error caused by intensity change during the measurement process can be eliminated, so that the calculation of the well inclination is only related to the direction and is not affected by the signal amplitude. After the core calculation part is completed, the formula also introduces two additional correction factors, which are and The first correction factor is a comprehensive correction for the Earth's gravity field and the relativistic effect, where It is a description of the relativistic gravitational redshift, reflecting the slight deformation of the gravitational field on the measured time and space as the depth of the well increases. Although this effect may be small under normal conditions, its introduction can significantly improve the reliability of the results for deep well operations or scenarios that require long-term high-precision measurements. The second correction factor It is used to simulate the exponential decay effect of depth on measurement accuracy, where Indicates atmospheric elevation. As the well depth increases, the sensor signal may be affected by changes in the external environment (such as temperature, pressure, magnetic field strength, etc.). This correction factor can dynamically compensate for the impact of these changes on the calculation results of the well inclination.

[0049] Embodiment 9: In step 3, the corrected azimuth is calculated by the following formula: ; in, To correct the azimuth.

[0050] Specifically, the core part of the formula is Here, Represents the projection vector of the geomagnetic field in the local navigation coordinate system, is the reconstructed signal vector obtained by signal reconstruction in step 1, and is the Coriolis force compensation vector calculated in step 2. By performing cross-product and dot-product operations on these three vectors, the formula attempts to capture the spatial relationship and mutual influence between them, thereby obtaining a preliminary estimate of the azimuth angle. Specifically, represents the cross product between the geomagnetic field vector and the reconstructed signal vector. This operation generates a new vector that is perpendicular to and The plane where the force is located reflects the relative direction and strength between the two. The dot product operation further quantifies the performance of these spatial relationships under the inertial effect caused by the rotation of the earth. This composite operation can effectively take into account the complex interaction between the geomagnetic field and the dynamic motion of the sensor, ensuring that the azimuth calculation not only relies on static magnetic field information, but also dynamically adapts to changes caused by rotation and motion in the downhole environment. By taking the modulus of the three vectors and multiplying them, the denominator ensures that the dot product result is within the dimensionless range, making The input value of the function is kept within a reasonable range (i.e. This normalization operation not only eliminates the influence between data of different magnitudes, but also ensures the stability and consistency of the calculation results, so that the calculation of the azimuth angle is not disturbed by the change of the sensor measurement amplitude.

[0051] in the formula The function is applied because the azimuth is essentially an angle, and the proportional relationship needs to be converted into an angle value through the inverse tangent function. In this way, the formula can convert the complex vector operation results into an angle value that is easy to understand and apply, and directly used for the output of well inclination and azimuth measurement. Next, the correction factor in the formula and It plays a role in further correction and adjustment. represents the local geomagnetic field strength, and is the standard strength of the Earth's magnetic field, which is 49.6 microteslas. , the formula realizes the normalization of the change of local geomagnetic field intensity. The introduction of this ratio is to eliminate the influence of the difference of geomagnetic field intensity under different geographical locations or geological conditions on the calculation of azimuth, ensuring that the calculation results can maintain consistent accuracy and reliability regardless of whether the geomagnetic field is strong or weak. The exponential term in the correction factor The inertial effect caused by the Earth's rotation is taken into account to make a slight correction to the measurement result. for , and the speed of light for The introduction of this exponential term is mainly to compensate for the slight inertial effect caused by the rotation of the earth. Especially in high-precision measurements, this slight correction can significantly improve the accuracy of the measurement results. The value of is very small, but in the downhole measurement environment with high precision requirements, this correction factor is effectively incorporated into the calculation in the form of an exponential function, ensuring that the correction of the azimuth is more accurate and stable.

[0052] The present invention is described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A high-precision well inclination and azimuth measurement method based on a multi-axis sensor, characterized in that: The method comprises: Step 1: Considering the influence of the earth's curvature and rotation, a local navigation coordinate system of the underground environment is established; in the local navigation coordinate system, the measurement signal of the four-axis sensor is reconstructed to obtain a reconstructed signal; Step 2: Based on the sensor quality of the four-axis sensor, the three-dimensional velocity components measured by the four-axis sensor and the geographic coordinate position of the four-axis sensor, the Coriolis force compensation vector is calculated by considering the influence of the Coriolis force caused by the rotation of the earth; Step 3: Calculate the projection of the geomagnetic field in the local navigation coordinate system to obtain the geomagnetic field projection vector; consider the influence of gravity, combine the geological density and bottom density in the downhole environment, and calculate the gravity compensation value; Step 4: Calculate the corrected well inclination and azimuth according to the gravity compensation value, Coriolis force compensation vector and geomagnetic field projection vector in combination with the reconstructed signal.

2. The high-precision well inclination and azimuth measurement method based on a multi-axis sensor as claimed in claim 1, characterized in that: The four-axis sensor includes a gyroscope, a magnetometer, a three-axis speedometer and a three-axis accelerometer.

3. The high-precision well inclination and azimuth measurement method based on a multi-axis sensor as claimed in claim 2, characterized in that: The local navigation coordinate system in step 1 Use the following formula to express it: ； in, is the average radius of the earth, which is 6371 km; is the height from the earth's center to the downhole measuring point where the four-axis sensor is located; is the geographical latitude of the downhole measuring point where the four-axis sensor is located; is the geographical longitude of the downhole measuring point where the four-axis sensor is located; is the angular velocity of the Earth’s rotation, and its value is , the unit is rad / s; is the speed of light; is the eccentricity of the Earth, and its value is 0.0818191908426.

4. The high-precision well inclination and azimuth measurement method based on a multi-axis sensor as claimed in claim 3, characterized in that: In step 1, the measurement signal of the four-axis sensor is reconstructed in the local navigation coordinate system by the following formula to obtain the reconstructed signal : ； in, is the X-axis acceleration component of the three-axis accelerometer; is the Y-axis acceleration component of the three-axis accelerometer; is the Z-axis acceleration component of the three-axis accelerometer; is the X-axis angular velocity component of the gyroscope; is the Y-axis angular velocity component of the gyroscope; is the initial well inclination angle, ； is the Earth's gravitational constant; is the geomagnetic field strength of the magnetometer; is the initial direction angle, ； is the X-axis geomagnetic field intensity component of the magnetometer; is the Y-axis geomagnetic field intensity component of the magnetometer; Represents the modulus length operation of a vector; is the standard strength of the Earth's magnetic field, with a value of 49.6 and a unit of microtesla; is the atmospheric scale height, which is 7.4 km.

5. The high-precision well inclination and azimuth measurement method based on a multi-axis sensor as claimed in claim 4, characterized in that: In step 2, the Coriolis force compensation vector is calculated using the following formula: : ； in, is the mass of the four-axis sensor; is the X-axis velocity component of the three-axis speedometer; is the Y-axis velocity component of the three-axis speedometer; is the Z-axis velocity component of the three-axis velocimeter.

6. The high-precision well inclination and azimuth measurement method based on a multi-axis sensor as claimed in claim 5, characterized in that: In step 3, the projection of the geomagnetic field in the local navigation coordinate system is calculated by the following formula: : ； in, is the geomagnetic inclination; is the magnetic declination; is the geomagnetic field attenuation coefficient, which is 640; is the temperature coefficient, and its value is 0.0033; is the current temperature; The standard temperature is 20 degrees Celsius.

7. The high-precision well inclination and azimuth measurement method based on a multi-axis sensor as claimed in claim 6, characterized in that: In step 3, the gravity compensation value is calculated by the following formula: : ； in, is the earth shape factor, and its value is 0.00108263; is an integer subscript index with an upper limit of 4, which simplifies the continuous density distribution of the strata into a 4-layer model, representing the crust, mantle, outer core and inner core respectively; For the The geological average density of the bottom layer is the set value; is the standard formation density, with a value of 2.67 and a unit of .

8. The high-precision well inclination and azimuth measurement method based on a multi-axis sensor as claimed in claim 6, characterized in that: In step 3, the corrected well inclination angle is calculated using the following formula: ； in, To correct the well inclination.

9. The high-precision well inclination and azimuth measurement method based on a multi-axis sensor as claimed in claim 8, characterized in that: In step 3, the corrected azimuth is calculated using the following formula: ； in, To correct the azimuth.

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