A 3D spatial horizontal well horizon calibration method based on control points

Abstract

The present invention relates to a method for calibrating the horizons of a three-dimensional horizontal well based on control points, belonging to the technical field of oil and gas exploration and development. The method is as follows: determining the approximate position of the horizontal well trajectory on the seismic section by using the average velocity field obtained from seismic data, determining the possible position of the target layer of the horizontal well on the seismic section by calibrating the synthetic record of the pilot well and the surrounding drilled wells, and analyzing the relationship between the position of the horizontal well trajectory on the seismic section and the seismic reflection isochrones; obtaining the average velocity at the well point by making the synthetic record of the drilled wells and the pilot well; obtaining the average velocity at the control point by geological stratification and interpreted horizons. Calibrating the average velocity field by using the average velocities at the well point and the control point to obtain a calibrated three-dimensional velocity field, and realizing the spatial horizon calibration of the horizontal well. The present invention is applicable to both the drilled horizontal well and the design of the trajectory and target point of the to-be-drilled horizontal well, guiding the drilling encounter rate of the target layer during the drilling of the horizontal well and improving the control degree of the trajectory.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas exploration and development, and particularly relates to a three-dimensional space horizontal well horizon calibration method based on control points. Background Technique

[0002] With the continuous deepening of oil and gas exploration and development, the exploration degree of conventional oil and gas reservoirs is getting higher and higher, the thickness of oil and gas layers and the physical properties of reservoirs are getting worse and worse, and the exploration efficiency is getting worse and worse. Therefore, unconventional oil and gas reservoirs such as mid-depth tight oil and gas and shale oil and gas in the central sag zone are important exploration targets.

[0003] Due to the tightness of unconventional oil and gas reservoir reservoirs, poor physical properties and permeability, drilling vertical wells and fracturing cannot achieve the purpose of efficient development. Deploying horizontal well drilling to connect non-connected oil and gas layers in the target interval and producing them together can greatly improve the oil and gas production of a single well and the exploration and development efficiency, and achieve scale reserve increase and efficient development.

[0004] In the process of deploying and researching horizontal wells, the horizon calibration of the horizontal section of horizontal wells has always been an important research topic in the process of oil and gas exploration and development. Many scholars have carried out research work in this regard. Some scholars construct virtual wells below the horizontal well target point and use the logging curves of the horizontal well section to resample the logging curves of the horizontal well section as the logging curves below the target point. Some scholars use the method of flattening the strata below the horizontal section of the horizontal well to generate a new data volume and perform horizon calibration of the horizontal section on the new data volume. These horizon calibration methods for the horizontal section are all carried out for specific stratigraphic structures and specific research objects, and are not representative. Especially in the study area, the vertical and horizontal changes of underground velocity are large, and the reflection characteristics of the seismic event axis of the 3D seismic data volume cannot reflect the true structural form. Due to the drastic change in velocity, the originally down-dipping strata in the time domain seismic data appear as up-dipping strata, creating an illusion of the structural form. Therefore, how to use 3D seismic data to calibrate the horizons of horizontal wells is worthy of in-depth study. Summary of the Invention

[0005] The purpose of the present invention is to provide a three-dimensional space horizontal well horizon calibration method based on control points to solve the problems of narrow application range and inaccurate horizon calibration of existing horizontal well horizon calibration methods.

[0006] The technical solution of the three-dimensional space horizontal well horizon calibration method based on control points provided by the present invention to solve the above technical problems is as follows: The method includes the following steps:

[0007] 1) Obtain the trajectory coordinate information of the drilled vertical wells, pilot wells and drilled horizontal wells in the study area;

[0008] 2) Conduct the horizon calibration of the pilot hole in the drilled wells, and calibrate the geological horizons of the pilot hole on the seismic section;

[0009] 3) Convert the root-mean-square velocity field obtained from the seismic data into an average velocity field; use the average velocity field to calibrate the trajectory of the drilled horizontal well on the time section and determine the approximate position of the horizontal well trajectory on the seismic section;

[0010] 4) Analyze the relationship between the position of the horizontal well trajectory on the seismic section and the seismic reflection isochrones in the time domain. When the position of the horizontal well trajectory on the seismic section is inconsistent with the seismic reflection isochrones, proceed to step 5);

[0011] 5) Produce the synthetic seismic records of the drilled wells and the pilot hole in the study area, conduct fine horizon calibration, and obtain the average velocity of the target interval of the drilled wells;

[0012] 6) Add control points at the sparse well locations in the study area, and determine the corresponding geological horizons at the control points based on the geological horizon data of the drilled wells around the control points, so as to obtain the average velocity of the target interval at the control points;

[0013] 7) Correct the average velocity field in step 3) according to the average velocity of the target interval of the drilled wells and the average velocity of the target interval at the control points;

[0014] 8) Perform time-depth conversion on the trajectory of the horizontal well in the 3D seismic data volume using the corrected average velocity field, so that the horizontal section of the horizontal well accurately falls on the corresponding seismic reflection isochrones, and finally achieve the horizon calibration of the horizontal well.

[0015] The beneficial effects of the present invention are as follows: The horizontal well horizon calibration method of the present invention can not only calibrate the horizons of the existing horizontal wells, but also calibrate the target points of the designed wells, guide the drilling rate of the target formation during the drilling process of the horizontal well, and improve the control degree of the trajectory.

[0016] Further, in order to obtain a more accurate average velocity at the control points, the steps of obtaining the average velocity at the control points in step 6) include:

[0017] a) Find at least one pair of drilled wells among the drilled wells around the added control points; each pair of drilled wells meets the following conditions: each drilled well in each pair of drilled wells is on a straight line with the control point, and is located at both ends of the control point respectively, and each drilled well is the closest to the control point at its corresponding end;

[0018] b) Determine the geological horizon data of the control point based on the geological horizon data of each pair of drilled wells. The formula is: Where D xThe geological stratification value of the control point, with the unit of m; D1 is the geological stratification value of the first drilled well in each pair of drilled wells, with the unit of m, and D2 is the geological stratification value of the second drilled well in each pair of drilled wells, with the unit of m; γ is the proportionality coefficient, γ = L1L2, where L1 is the distance between the first drilled well and the control point in each pair of drilled wells, with the unit of m, and L2 is the distance between the second drilled well and the control point in each pair of drilled wells, with the unit of m;

[0019] c) Determine the average velocity at the control point according to the geological stratification value of the control point. The formula is: Where, V tx Is the average velocity at the control point, with the unit of m / s, and T x Is the two-way travel time of the control point in the time domain, with the unit of s.

[0020] In order to further improve the calculation accuracy of the average velocity at the control point, find more than two pairs of drilled wells among the drilled wells around the added control point. For each pair of drilled wells, obtain the corresponding geological stratification values according to steps b) and c), calculate the mean value of each geological stratification value, and take the mean value as the geological stratification value of the control point.

[0021] In order to obtain a better correction effect, the steps for correcting the average velocity field obtained from seismic data include:

[0022] Ⅰ) Calculate the difference between the average velocity obtained from seismic data at the well point and the average velocity obtained from the drilled wells and the control point at the well point in the target interval to obtain the difference in average velocity between the well point and the control point. The formula is: ΔV av = V s - V w , where ΔV av Is the difference in average velocity between the well point and the control point, with the unit of m / s; V s Is the average velocity obtained from seismic data at the well point, with the unit of m / s; V w Is the average velocity obtained from the drilled wells and the control point at the well point, with the unit of m / s;

[0023] Ⅱ) Under the control of the interpreted horizon, perform spatial interpolation on the difference in average velocity between the well point and the control point to obtain a three-dimensional average velocity error field;

[0024] Ⅲ) Correct the average velocity field obtained from seismic data with the three-dimensional average velocity error field. The formula is: V av = V s - ΔV, where V av Is the corrected average velocity value, with the unit of m / s; ΔV is the three-dimensional average velocity error field, with the unit of m / s; V s Is the average velocity obtained from seismic data, with the unit of m / s.

[0025] Furthermore, in order to improve the rationality of adding control points, it is determined whether the well points are sparse according to the distance between the drilled wells and the severity of the velocity change at the well points.

[0026] Furthermore, in order to achieve fine horizon calibration, in step 5), synthetic seismic records of the drilled wells are made according to the acoustic wave, density and VSP data of the drilled wells.

[0027] Furthermore, the sparse area refers to the position where the planar position of the well points is greater than 2 km. Description of the Drawings

[0028] Figure 1 is a flowchart of the three-dimensional space horizontal well calibration method based on control points of the present invention;

[0029] Figure 2 is a schematic diagram of geological stratification for obtaining control points in an embodiment of the present invention;

[0030] Figure 3 is a calibration diagram of the synthetic record of the pilot hole of Well SP1 in an embodiment of the present invention;

[0031] Figure 4 is a calibration diagram of the horizontal well trajectory using the average velocity field obtained from the seismic root-mean-square velocity in an embodiment of the present invention;

[0032] Figure 5 is a process diagram of velocity correction using well points and control points in an embodiment of the present invention;

[0033] Figure 6 is a schematic diagram of the corrected velocity field in an embodiment of the present invention;

[0034] Figure 7 is a calibration result diagram of the horizontal well in an embodiment of the present invention;

[0035] Figure 8 is a horizontal well spatial horizon calibration diagram in an embodiment of the present invention. Detailed Embodiments

[0036] The following further describes the detailed embodiments of the present invention with reference to the drawings.

[0037] The technical concept of the present invention lies in: based on formation correlation and fine three-dimensional seismic structure interpretation, accurately determine the geological stratification of the drilled wells and the geological stratification at the control points. By making synthetic seismograms of the drilled wells, obtain the average velocity at the well points; by using the geological stratification and interpreted horizons, obtain the average velocity at the control points. Use the average velocities at the well points and the control points to correct the average velocity field obtained from seismic data, obtain the corrected three-dimensional velocity field, and achieve the spatial horizon calibration of horizontal wells. The method of the present invention can not only calibrate the horizons of existing horizontal wells, but also calibrate the target points of the designed wells, guide the drilling encounter rate of the target formation during the drilling of horizontal wells, and improve the control degree of the trajectory.

[0038] The above technical concept involves three-dimensional seismic data, which contains information on both the kinematics and dynamics of seismic waves. The waveform characteristics of the kinematics of three-dimensional seismic data can be fully utilized to determine the underground structural form, and the reflection information of three-dimensional seismic wave dynamics can be used to predict information such as the lithology and physical properties of the formation.

[0039] It also involves synthetic seismograms. Through the horizon calibration of synthetic seismograms, the depth-domain information revealed by drilling is calibrated onto the three-dimensional seismic data volume in the time domain. Use the physical properties, lithology, and hydrocarbon-bearing results encountered in the drilled horizontal wells for reservoir prediction and evaluation, providing a basis for the next well location deployment.

[0040] Based on the above technical concept, as Figure 1 shown, in order to achieve the horizon calibration of horizontal wells, the three-dimensional spatial horizontal well calibration method based on control points of the present invention includes the following steps:

[0041] 1) Obtain the trajectory coordinate information of the vertical wells, pilot holes, and drilled horizontal wells in the study area;

[0042] 2) Conduct horizon calibration for the pilot holes in the drilled wells, and calibrate the geological stratification of the pilot holes on the seismic section;

[0043] 3) Convert the root-mean-square velocity field obtained from seismic data into an average velocity field; use the average velocity field to calibrate the trajectories of the drilled horizontal wells on the time section, and determine the approximate positions of the horizontal well trajectories on the seismic section;

[0044] 4) Analyze the relationship between the position of the horizontal well trajectory on the seismic section and the seismic reflection isochrones in the time domain. When the position of the horizontal well trajectory on the seismic section is inconsistent with the seismic reflection isochrones, proceed to step 5);

[0045] 5) Make synthetic seismic records of the drilled wells and pilot holes in the study area, conduct fine horizon calibration, and obtain the average velocity of the target formation section of the drilled wells;

[0046] 6) Add control points at sparse well locations in the study area, and determine the corresponding geological stratification at the control points based on the geological stratification data of the drilled wells around the control points, so as to obtain the average velocity of the target interval at the control points.

[0047] 7) Correct the average velocity field described in step 3) according to the average velocity of the target interval of the drilled wells and the average velocity of the target interval at the control points.

[0048] 8) Perform time-depth conversion on the trajectory of the horizontal well in the 3D seismic data volume using the corrected average velocity field, so that the horizontal section of the horizontal well accurately falls on the reflection isochron corresponding to the 3D seismic data, and finally realize the horizon calibration of the horizontal well.

[0049] As a preferred implementation method, the steps of obtaining the average velocity of the target interval at the control points in step 6) include: a) Find at least a pair of drilled wells among the drilled wells around the added control points; each pair of drilled wells meets the following conditions: each drilled well in each pair of drilled wells is on a straight line with the control point, and is located at both ends of the control point respectively, and each drilled well is the closest to the control point at its corresponding end.

[0050] b) Determine the geological stratification data of the control point based on the geological stratification data of each pair of drilled wells. The formula is:

[0051]

[0052] In the formula, D x is the geological stratification value of the control point, in m; D1 is the geological stratification value of the first drilled well in each pair of drilled wells, in m, and D2 is the geological stratification value of the second drilled well in each pair of drilled wells, in m.

[0053] γ is the proportionality coefficient, and the calculation formula is:

[0054] γ = L1L2(2)

[0055] where L1 is the distance between the first drilled well and the control point in each pair of drilled wells, in m, and L2 is the distance between the second drilled well and the control point in each pair of drilled wells, in m;

[0056] c) Determine the average velocity at the control point according to the geological stratification value of the control point. The formula is:

[0057]

[0058] where V tx is the average velocity at the control point, in m / s, and T x is the two-way travel time of the control point in the time domain, in s.

[0059] When looking for more than two pairs of drilled wells among the drilled wells around the increased control points, each pair of drilled wells obtains the corresponding geological stratification values according to steps b) and c), calculates the average value of each geological stratification value, and takes the average value as the geological stratification value of the control point.

[0060] Generally, it is judged whether the well points are sparse according to the distance between the drilled wells and the severity of the velocity change at the well points.

[0061] As Figure 2 shown, add a control point Px at the sparse well points. Select appropriate drilled wells W1, W2, W3, and W4 from the drilled wells around the control point Px. Determine the corresponding geological stratification at the control point according to the geological stratification data of the drilled wells W1, W2, W3, and W4, so as to obtain the average velocity at the control point. When selecting the drilled wells, take a straight line segment with the control point Px as the center. At this time, the drilled wells W1 and W2 fall on the straight line segment and are the closest to the control point Px at both ends of the control point Px. Similarly, obtain the drilled well pair W3 and W4. Calculate the distance L1 between W1 and Px, the distance L2 between W2 and Px, the distance L3 between W3 and Px, and the distance L4 between W4 and Px. Calculate the proportionality coefficients γ1 and γ2 respectively according to formula (2):

[0062]

[0063] The proportionality coefficients γ1 and γ2 calculated according to the geological stratification values D1, D2, D3, and D4 corresponding to the drilled wells W1, W2, W3, and W4, and calculate the two geological stratification values D x1 、D x2 of the control point Px according to formula (1):

[0064]

[0065] Calculate D x1 、D x2 mean value, that is, (D x1 +D x2 ) / 2, and take this mean value as the geological stratification value of the control point Px.

[0066] As a preferred implementation method, the steps for correcting the average velocity field obtained from seismic data include:

[0067] Ⅰ) Calculate the difference between the average velocity V s obtained from seismic data at the well points and the average velocity V w obtained from the drilled wells and control points at the well points in the target interval, and obtain the difference in average velocity between the well points and the control points;

[0068] ΔV av =V s -Vw (4)

[0069] Wherein, ΔV av is the difference between the average velocities at the well point and the control point, with the unit of m / s; V s is the average velocity obtained from seismic data at the well point, with the unit of m / s; V w is the average velocity obtained from the drilled wells and the control point at the well point, with the unit of m / s.

[0070] II) Under the control of the interpreted horizon, perform spatial interpolation on the difference between the average velocities at the well point and the control point to obtain a three-dimensional average velocity error field;

[0071] III) Correct the average velocity field obtained from seismic data using the three-dimensional average velocity error field. The formula is:

[0072] V av = V s -ΔV (5)

[0073] Wherein, V av is the corrected average velocity value, with the unit of m / s; ΔV is the three-dimensional average velocity error field, with the unit of m / s; V s is the average velocity obtained from seismic data, with the unit of m / s.

[0074] As a preferred implementation manner, synthetic seismic records of the drilled wells are made according to the acoustic wave, density and VSP data of the drilled wells.

[0075] On the basis of the above steps 1) to 8), the horizon calibration of the horizontal well is realized. Combining the amplitude change characteristics of the seismic reflection event axis between the pilot well and the horizontal section of the horizontal well, the spatial variations of the lithology, physical properties and oil and gas bearing properties of the target interval are studied. The use of the changes in seismic attributes and seismic reflection characteristics can guide the adjustment of the horizontal well trajectory and improve the hitting rate.

[0076] The following takes a specific study area as an example to elaborate in detail on the specific implementation process of the horizontal well calibration method of the present invention.

[0077] The study area is located in the central deep depression area of the sag. This area is the subsidence center, sedimentation center and oil generation center of the sag. There are multiple provenances developed in this area, including the delta sand bodies from the north, and small gravel rock bodies from the south and east.

[0078] The source rocks in the study area are lacustrine mudstones of the third member of the nuclear section in the sag. The oil and gas reservoirs mainly come from the proximal delta in the north and small gravel rock bodies in the east. At the same time, various types of oil and gas reservoirs are developed in this area. Lithologic lateral pinch-out oil reservoirs are developed in the middle and shallow layers, tight sandstone oil and gas reservoirs are developed in the deep layers, and unconventional oil and gas reservoirs are also developed, with good hydrocarbon accumulation conditions.

[0079] This area is a multi-source development area, where dolomite develops in the middle and shallow strata, resulting in large vertical and horizontal variations in formation velocity. The seismic reflection characteristics of the seismic profile cannot represent the underground structural morphology.

[0080] During the exploration of unconventional oil and gas reservoirs and deep tight oil and gas reservoirs in this area, in order to improve exploration efficiency, it is necessary to deploy horizontal well drilling. To do a good job in the deployment of horizontal wells, it is necessary to carry out horizon calibration of the existing vertical wells, pilot holes and horizontal wells to guide the prediction of sweet spots in unconventional reservoirs and the deployment of horizontal wells.

[0081] To achieve the spatial horizon calibration of horizontal wells, work is carried out according to the Figure 1 method process shown.

[0082] First, collect the trajectory coordinate information and geological stratification information of the existing vertical wells, pilot holes and horizontal wells in the deep depression area and its periphery. Collect sonic, density, GR and other logging data of 40 wells, VSP seismic logging of 8 wells, and seismic root-mean-square velocity field data.

[0083] Secondly, use the sonic and density logging data of the pilot hole to make synthetic seismograms. Figure 3 This is the synthetic seismogram calibration map of the SP1 pilot hole. It can be seen from Figure 3 that for the T4 reflection layer, the geological stratification is 1794.4 m, and the corresponding seismic reflection time is 1287.5 ms; for the T51 reflection layer, the geological stratification is 2000.4 m, and the corresponding seismic reflection time is 1393.3 ms; for the T52 reflection layer, the geological stratification is 2257 m, and the corresponding seismic reflection time is 1535 ms; for the T53-1 reflection layer, the geological stratification is 2436 m, and the corresponding seismic reflection time is 1642 ms; for the T53-2 reflection layer, the geological stratification is 2448.1 m, and the corresponding seismic reflection time is 1650.1 ms.

[0084] Then, convert the seismic root-mean-square velocity field in the deep depression area into an average velocity field. Use this average velocity field to calibrate the trajectory of the horizontal well on the time section. Figure 4 This is the calibration map of the horizontal well trajectory using the average velocity field obtained from the seismic root-mean-square velocity. Figure 4 The value line under SP1 in the figure is the pilot hole, and the stratification is the result of horizon calibration. The dotted line under SP1 is the position map of the horizontal well trajectory calibrated using the average velocity field obtained from the seismic root-mean-square velocity. It can be seen from the figure that this velocity field is inaccurate and only roughly determines the position of the horizontal well trajectory path on the seismic section.

[0085] To carry out fine calibration of the horizontal section of the horizontal well, it is necessary to establish a fine velocity field.

[0086] Synthetic records were made from the sonic, density, and VSP data of 40 wells collected, and fine horizon calibration was carried out to obtain the velocity values at the well points. At the same time, 2 control points were added where the drilling density was sparse, and the corresponding geological horizons at the control points were determined based on the geological stratification data of the wells around the control points, so as to obtain the average velocity at the control points.

[0087] The seismic average velocity field was corrected using the average velocities at the well points and the control points. Figure 5 It is the process diagram of velocity correction for the well points and the control points.

[0088] Figure 6 The average velocity field obtained from the seismic data was corrected using the average velocity of the target interval of the drilled wells and the average velocity of the target interval at the control points.

[0089] The time-depth conversion of the trajectory of the SP1 horizontal well was carried out in the three-dimensional seismic data volume using the corrected average velocity field to determine which seismic reflection interface's in-phase axis the horizontal section of the horizontal well falls on. Figure 7 It is the calibration result diagram of the SP1 horizontal well. Figure 8 It is the spatial horizon calibration diagram of the SP1 horizontal well. It can be seen from the figure that the horizontal section of the SP1 well passes through the shale interval.

[0090] Combined with the amplitude variation characteristics of the seismic reflection in-phase axis of the pilot well and the horizontal section of the horizontal well, through the comparative analysis of the actual drilling logging, coring, and logging curves, the drilling results of this horizontal well are consistent with the deployment and calibration results.

[0091] At the same time, using the spatial horizon calibration technology of this horizontal well, it guided the trajectory adjustment and hitting rate of the newly deployed horizontal wells, making the deployed horizontal wells achieve the expected results.

Claims

1. A three-dimensional space horizontal well horizon calibration method based on control points, characterized in that The method includes the following steps: 1) Obtain the trajectory coordinate information of vertical wells, pilot holes, and horizontal wells that have been drilled in the study area; 2) Conduct horizon calibration for the pilot holes in the wells that have been drilled, and calibrate the geological horizons of the pilot holes on the seismic profile; 3) Convert the root-mean-square velocity field obtained from the seismic data into an average velocity field; use the average velocity field to calibrate the trajectory of the horizontal wells that have been drilled on the time section, and determine the approximate position of the horizontal well trajectories on the seismic profile; 4) Analyze the relationship between the position of the horizontal well trajectories on the seismic profile and the seismic reflection isochrones in the time domain. When the position of the horizontal well trajectories on the seismic profile is inconsistent with the seismic reflection isochrones, proceed to step 5); 5) Make synthetic seismic records of the wells and pilot holes that have been drilled in the study area, conduct fine horizon calibration, and obtain the average velocity of the target interval of the wells that have been drilled; 6) Add control points at sparse well locations in the study area, and find at least one pair of wells that have been drilled around the added control points; each pair of wells meets the following conditions: each well in each pair of wells is on a straight line with the control point, and is located at both ends of the control point respectively, and each well is the closest to the control point at its respective end; Determine the geological stratification data of the control point based on the geological stratification data of each pair of drilled wells. The formula is: In the formula, D x is the geological stratification value of the control point, with the unit of m; D1 is the geological stratification value of the first drilled well in each pair of drilled wells, with the unit of m, and D2 is the geological stratification value of the second drilled well in each pair of drilled wells, with the unit of m; γ is the proportionality coefficient, γ = L1 / L2, where L1 is the distance between the first drilled well and the control point in each pair of drilled wells, with the unit of m, and L2 is the distance between the second drilled well and the control point in each pair of drilled wells, with the unit of m; Determine the average velocity of the target interval at the control point according to the geological stratification value of the control point. The formula is: where V tx is the average velocity of the target interval at the control point, with the unit of m / s, and T x is the two-way travel time of the control point in the time domain, with the unit of s; 7) Correct the average velocity field described in step 3) according to the average velocity of the target interval of the wells that have been drilled obtained in step 5) and the average velocity of the target interval at the control points obtained in step 6); 8) Perform time-depth conversion on the trajectories of the horizontal wells in the 3D seismic data volume using the corrected average velocity field, so that the horizontal sections of the horizontal wells accurately fall on the corresponding seismic reflection isochrones, and finally achieve horizontal well horizon calibration.

2. The three-dimensional space horizontal well horizon calibration method based on control points according to claim 1, wherein Find more than two pairs of wells that have been drilled around the added control points. For each pair of wells, obtain the corresponding geological horizon values according to step 6), calculate the average value of the various geological horizon values, and use the average value as the geological horizon value of the control point.

3. The method for calibrating the horizons of a three-dimensional horizontal well based on control points according to claim 1 or 2, characterized in that The steps for correcting the average velocity field obtained from the seismic data include: Ⅰ) Calculate the difference between the average velocity obtained from seismic data at the well point and the average velocity obtained from the drilled wells and control points at the well point in the target interval, to obtain the difference in average velocity between the well point and the control point. The formula is: ΔV av = V s - V w , where ΔV av is the difference in average velocity between the well point and the control point, with the unit of m / s; V s is the average velocity obtained from seismic data at the well point, with the unit of m / s; V w is the average velocity obtained from the drilled wells and control points at the well point, with the unit of m / s; Ⅱ) Under the control of the interpreted horizons, perform spatial interpolation on the difference between the average velocities at the well points and the control points to obtain a 3D average velocity error field; Ⅲ) Correct the average velocity field obtained from seismic data using the three-dimensional average velocity error field. The formula is: V av = V s - ΔV, where V av is the corrected average velocity value, with the unit of m / s; ΔV is the three-dimensional average velocity error field, with the unit of m / s; V s is the average velocity obtained from seismic data, with the unit of m / s.

4. The method for calibrating the horizons of a three-dimensional horizontal well based on control points according to claim 3, wherein Judge whether the well locations are sparse according to the distance between the wells that have been drilled and the severity of the velocity change at the well points.

5. The method for calibrating the horizons of a three-dimensional horizontal well based on control points according to claim 3, wherein In step 5), make synthetic seismic records of the wells that have been drilled according to the sonic, density, and VSP data of the wells that have been drilled.

6. The method for calibrating the horizons of a three-dimensional horizontal well based on control points according to claim 1, wherein The sparse locations refer to locations where the planar position of the well points is greater than 2 km.

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