A method and apparatus for real-time formation tracking while drilling a highly deviated well

Abstract

The present application belongs to the technical field of oil and gas reservoir exploration and development, and particularly relates to a method and device for real-time formation tracking while drilling in a high-inclination well. The method determines the formation attribution and the intersection relationship between the vertical well and the formation by marking the real-time trajectory of the vertical well on seismic data, constructs a processing model for depth correction of logging-while-drilling curves under different intersection relationships between the real-time trajectory of the vertical well and the formation, realizes the correction and processing of the depth of the logging-while-drilling curves, and determines whether the real-time trajectory of the vertical well enters the intended sub-divided formation or the sweet spot section by comparing the curve shapes of the corrected logging-while-drilling curves and the existing standard well completion logging curves. The method can accurately track the position of the sub-divided formation where the real-time trajectory of the vertical well is located, thereby ensuring the accurate targeting of the vertical well and providing a scientific basis for the reasonable and efficient exploration and development of oil and gas reservoirs.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas reservoir exploration and development technology, specifically relating to a method and device for real-time formation tracking while drilling in highly deviated wells. Background Technology

[0002] With the advancement of oil and gas exploration and development technologies, drilling of complex well types such as highly deviated wells and horizontal wells targeting target oil and gas reservoirs is becoming increasingly common. As logging while drilling is a drilling technology that can both drill through the formation and measure formation information in real time, its application in these complex well types is also widespread. The types of logging curves corresponding to logging while drilling are also constantly enriched due to the development of logging technology. However, due to factors such as cost, the most commonly measured logging curves in logging while drilling are logging gamma, logging resistivity, and logging sonic transit time.

[0003] Because highly deviated and horizontal wells have complex well configurations and diverse well trajectory-formation interactions, and due to the lower vertical resolution of seismic data compared to well logging data, well trajectory calibration on seismic data can only determine the approximate formation of the drilling well. Its ability to identify sub-strata within that formation is limited. Accurate identification of these sub-strata determines whether the drilling trajectory hits the target. This sub-strata identification can only be determined by comparing the logging curves obtained during drilling (with vertical correction) with existing standard well completion logging curves. However, due to the uncertainty of the formation attitude encountered during drilling, the well trajectory-formation interaction can have different relationships: bedding-parallel and anti-bedding-parallel. Bedding-parallel interaction occurs when the well trajectory's azimuth and the formation's dip direction are the same. When drilling through a formation, the thickness of the true formation encountered is significantly less than the vertical thickness corrected according to the wellbore trajectory's inclination and azimuth. In reverse layer junctions, the well trajectory's azimuth and the formation's dip direction are opposite. At these junctions, the thickness of the true formation encountered is significantly greater than the vertical thickness corrected according to the wellbore trajectory's inclination and azimuth. This results in significant stretching or compression of the logging-while-drilling curves corrected for the vertical depth of the forward drilling within the same formation set. Consequently, the curves exhibit poor comparability with existing standard well completion logging curves, leading to subjective qualitative and inaccurate formation comparison results. The subdivided formation attribution of the forward drilling is misclassified, resulting in the forward drilling trajectory failing to enter the designated subdivided formations or sweet spots as required. This hinders the rational and efficient exploration and development of the corresponding oil and gas reservoirs. Summary of the Invention

[0004] The purpose of this invention is to provide a method for real-time formation tracking while drilling in highly deviated wells, so as to solve the problems of human qualitative analysis and inaccuracy in existing methods for real-time formation tracking while drilling in highly deviated wells.

[0005] The second objective of this invention is to provide a real-time formation tracking device for high-angle wells during drilling, in order to solve the above-mentioned problems.

[0006] To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0007] A method for real-time formation tracking while drilling in highly deviated wells includes the following steps:

[0008] (1) Obtain data on all strata and sub-strata of existing standard wells around the drilling well, as well as well completion logging data, real-time well inclination, azimuth, logging-while-drilling curves of the drilling well, and seismic data around the drilling well.

[0009] (2) Using the calibration of existing standard well completion logging curves on seismic data, determine the stratigraphic interfaces of each stratum on the seismic body, and determine the dip angle and dip direction of each stratum;

[0010] (3) Use the calibration of the real-time trajectory of the drilling well on the seismic data to determine the stratigraphic affiliation of the location of the drilling well, and determine the intersection relationship between the real-time trajectory of the drilling well and each stratigraphic stratum.

[0011] (4) Construct a depth correction processing model for logging-while-drilling curves under different intersection relationships between the real-time trajectory of the drilling and the formation, carry out depth correction processing of the logging-while-drilling curves based on the logging-while-drilling curve depth correction processing model, and determine the corrected logging-while-drilling curves.

[0012] (5) In the formations encountered by the real-time trajectory of the drilling, the logging-while-drilling curve after drilling correction is compared with the completion logging curve of the existing standard well to determine whether the real-time trajectory of the drilling has entered the predetermined subdivided formation or sweet spot.

[0013] The real-time formation tracking method for high-angle wells provided by this invention combines the drilling characteristics of high-angle wells and the intersection relationship between the well trajectory and the bottom layer to correct the logging-while-drilling curve. It can accurately track the subdivided formation location of the real-time trajectory of the drilling, thereby ensuring that the drilling accurately hits the target and providing a scientific basis for the rational and efficient exploration and development of oil and gas reservoirs.

[0014] Preferably, in step (3), the junction relationship includes bedding plane junction and reverse bedding plane junction. By classifying the junction relationship into two types, bedding plane junction and reverse bedding plane junction, the formation characteristics encountered by the drilling of highly deviated wells can be classified, thereby facilitating subsequent logging curve depth correction.

[0015] Preferably, in step (4), the logging-while-drilling curve depth correction processing model is:

[0016]

[0017] In equation (1), D C1 D is the corrected depth of the first depth sampling point. C(i+1) D is the corrected depth of the (i+1)th depth sampling point.A1 D represents the original depth of the first depth sampling point. Ai Let D be the original depth of the i-th depth sampling point. A(i+1) α represents the original depth of the (i+1)th depth sampling point, all in meters; i is the sampling point number, an integer starting from 1; α is the dip angle of the formation, in degrees; β is the dip direction of the formation, in degrees; θ is the inclination angle of the forward drilling, in degrees; γ is the azimuth angle of the forward drilling, in degrees; when the intersection relationship between the real-time trajectory of the forward drilling and each formation is a joint intersection, the “±” in equation (1) is taken as “-”; when the intersection relationship between the real-time trajectory of the forward drilling and each formation is a joint intersection, the “±” in equation (1) is taken as “+”. Through the above-mentioned logging-while-drilling curve depth correction processing model, real-time and effective depth correction of the logging-while-drilling curve can be achieved, and the corrected logging-while-drilling curve has good consistency with the standard well completion logging curve.

[0018] A real-time formation tracking device for high-angle wells during drilling includes the following functional modules:

[0019] Data acquisition module: Acquires data on all strata and sub-strata of existing standard wells around the drilling well, as well as well completion logging data, real-time well inclination, azimuth, logging-while-drilling curves of the drilling well, and seismic data around the drilling well.

[0020] Module for determining the interface and attitude of each stratum: Using existing standard well completion logging curves on seismic data, the interface of each stratum on the seismic body is determined, and the dip angle and dip direction of each stratum are determined;

[0021] The module for determining the intersection relationship between the real-time trajectory of the drilling well and the formation: It uses the calibration of the real-time trajectory of the drilling well on seismic data to determine the formation at the location of the drilling well and to determine the intersection relationship between the real-time trajectory of the drilling well and each formation.

[0022] The logging-while-drilling curve depth correction processing module: Constructs a logging-while-drilling curve depth correction processing model under different intersection relationships between the real-time trajectory of the drilling and the formation, performs depth correction processing on the logging-while-drilling curve based on the logging-while-drilling curve depth correction processing model, and determines the corrected logging-while-drilling curve.

[0023] Formation comparison module: In the formations encountered by the real-time trajectory of the drilling operation, the logging-while-drilling curves after drilling correction are compared with the completion logging curves of existing standard wells to determine whether the real-time trajectory of the drilling operation has entered the predetermined subdivided formations or sweet spots.

[0024] The real-time formation tracking device for high-angle wells provided by this invention can accurately track the subdivided formation location of the real-time trajectory of the drilling well, thereby optimizing the trajectory so that the drilling well enters the predetermined subdivided formation or sweet spot, ensuring that the drilling well accurately hits the target, and thus achieving precise drilling encounters with oil and gas reservoirs.

[0025] Preferably, in the module for determining the intersection relationship between the real-time drilling trajectory and the formation, the intersection relationship includes in-seam intersection and reverse-seam intersection. By classifying the intersection relationship into in-seam intersection and reverse-seam intersection, the characteristics of the formation encountered in highly deviated wells can be categorized, thereby facilitating subsequent logging curve depth correction.

[0026] Preferably, in the logging-while-drilling curve depth correction processing module, the logging-while-drilling curve depth correction processing model is:

[0027]

[0028] In equation (1), D C1 D is the corrected depth of the first depth sampling point. C(i+1) D is the corrected depth of the (i+1)th depth sampling point. A1 D represents the original depth of the first depth sampling point. Ai Let D be the original depth of the i-th depth sampling point. A(i+1) α represents the original depth of the (i+1)th depth sampling point, all in meters; i is the sampling point number, an integer starting from 1; α is the dip angle of the formation, in degrees; β is the dip direction of the formation, in degrees; θ is the inclination angle of the forward drilling, in degrees; γ is the azimuth angle of the forward drilling, in degrees; when the intersection relationship between the real-time trajectory of the forward drilling and each formation is in-seam intersection, the "±" in equation (1) is taken as "-"; when the intersection relationship between the real-time trajectory of the forward drilling and each formation is in-verse intersection, the "±" in equation (1) is taken as "+". Through the above-mentioned logging-while-drilling curve depth correction processing model, real-time and effective depth correction of the logging-while-drilling curve can be achieved, and the corrected logging-while-drilling curve has good consistency with the standard well completion logging curve. Attached Figure Description

[0029] Figure 1 This is a flowchart of the real-time formation tracking method for high-angle wells during drilling according to the present invention;

[0030] Figure 2 This is a map showing the well trajectory and formation distribution of the standard well T10 and the drilling well T12 in the Tongnanba gas field, compiled using the real-time formation tracking method for high-angle wells in this invention, determined by seismic calibration.

[0031] Figure 3This is a theoretical model diagram of depth correction under different junction relationships between the well and the formation, compiled using the real-time formation tracking method for high-angle wells in drilling according to the present invention.

[0032] Figure 4 Natural gamma curve during drilling of well T12 in the Tongnanba gas field after vertical correction at conventional depth;

[0033] Figure 5 This is a comparison diagram of the natural gamma ray curve morphology of well T12 in the Tongnanba gas field after depth correction and that of well T10, compiled using the real-time formation tracking method for high-angle wells of the present invention. Detailed Implementation

[0034] This invention provides a method for real-time formation tracking while drilling in highly deviated wells, comprising the following steps:

[0035] 1) Obtain data on all strata and sub-strata of existing standard wells around the drilling well, as well as well completion logging data, real-time well inclination, azimuth, logging-while-drilling curves of the drilling well, and seismic data around the drilling well.

[0036] 2) Use existing standard well completion logging curves to calibrate on seismic data to determine the stratigraphic interfaces of each stratum on the seismic body, and determine the dip angle and dip direction of each stratum;

[0037] 3) Use the calibration of the real-time trajectory of the drilling well on seismic data to determine the stratigraphic affiliation of the location of the drilling well, and determine the intersection relationship between the real-time trajectory of the drilling well and each stratigraphic unit.

[0038] 4) Construct a depth correction processing model for logging-while-drilling curves under different intersection relationships between the real-time trajectory of the drilling operation and the formation. Select the corresponding depth correction processing model for logging-while-drilling curves according to the intersection relationship between the real-time trajectory of the drilling operation and each formation, carry out depth correction processing of the logging-while-drilling curves, and determine the corrected logging-while-drilling curves.

[0039] 5) In the formations encountered by the real-time trajectory of the drilling operation, the logging-while-drilling curves after drilling correction are compared with the completion logging curves of existing standard wells to determine whether the real-time trajectory of the drilling operation has entered the predetermined subdivided formations or sweet spots, and the well trajectory is optimized in a timely manner until the drilling is completed.

[0040] The aforementioned real-time formation tracking method for highly deviated wells determines the formation affiliation and inter-formation relationship of the well location by calibrating the real-time well trajectory on seismic data. It then constructs a depth correction model for logging-while-drilling curves under different inter-formation relationships, correcting the depth of the logging-while-drilling curves. By comparing the corrected logging-while-drilling curves with existing standard well completion logging curves, it determines whether the real-time well trajectory has entered a predetermined sub-formation or sweet spot. This method accurately tracks the sub-formation location of the real-time well trajectory, ensuring precise well target entry and providing a scientific basis for the rational and efficient exploration and development of oil and gas reservoirs.

[0041] In step 1), the periphery of the main drilling well refers to a certain area where the overall formation deposition thickness and reservoir properties are relatively stable. Among them, the standard wells around the main drilling well are completed wells whose well trajectories intersect each formation as perpendicularly as possible and include all formations designed to be encountered by the main drilling well.

[0042] In step 3), there are two types of intersection relationships between the real-time trajectory of the drilling and the formations: one is in-seam intersection, and the other is in-seam intersection.

[0043] Step 4) constructs a depth correction model for logging-while-drilling curves under different intersection relationships between the real-time drilling trajectory and the formation:

[0044]

[0045] In equation (1), D C1 D is the corrected depth of the first depth sampling point. C(i+1) D is the corrected depth of the (i+1)th depth sampling point. A1 D represents the original depth of the first depth sampling point. Ai Let D be the original depth of the i-th depth sampling point. A(i+1) α is the original depth of the (i+1)th depth sampling point, all in meters; i is the sampling point number, an integer starting from 1; α is the dip angle of the formation, in degrees; β is the dip direction of the formation, in degrees; θ is the inclination angle of the drilling, in degrees; γ is the azimuth angle of the drilling, in degrees; when the intersection relationship between the real-time trajectory of the drilling and each formation is in-stratum intersection, the “±” in equation (1) is taken as “-”; when the intersection relationship between the real-time trajectory of the drilling and each formation is in-stratum intersection, the “±” in equation (1) is taken as “+”.

[0046] In step 4), using the formation dip and dip determined in step 2), and based on the intersection relationship between the real-time drilling trajectory in step 3 and each formation, the corresponding logging-while-drilling curve depth correction processing model in step 4 is selected to perform depth correction processing on the logging-while-drilling curves, thus determining the corrected logging-while-drilling curves. Specifically, the original depth of each sampling point of each logging-while-drilling curve is replaced with the corrected depth to determine the corrected logging-while-drilling curves.

[0047] The implementation process of the present invention will be described in detail below with reference to specific embodiments.

[0048] Example 1

[0049] The flowchart of the real-time formation tracking method for high-angle wells during drilling in this embodiment is as follows: Figure 1 As shown, it includes the following steps:

[0050] 1) Acquire data on various formations and sub-formations of existing standard wells surrounding the drilling well, as well as completion logging data, real-time well inclination, azimuth, logging-while-drilling curves of the drilling well, and seismic data surrounding the drilling well:

[0051] The main development stratum of the Tongnanba Gas Field is the Xujiahe Formation of the Triassic. Within this formation, the sedimentary thickness and reservoir properties are relatively stable. Formation A is the primary target stratum of the gas field. Well T12 is a currently drilled well in the Tongnanba Gas Field, with a designed maximum inclination of 85°. The completed target stratum is sub-stratum A4 within Formation A. Well T10 is a completed well, 80m from the wellhead of Well T12. Preliminary geological studies indicate that Wells T12 and T10 have similar stratigraphic and reservoir characteristics. Well T10 is a vertical well in the Tongnanba gas field. The well trajectory of Well T10 intersects the strata in each region at a near-vertical angle and drills through stratum A. Well T10 has relatively complete data and meets the criteria for a standard well. Therefore, Well T10 was selected as the standard well. Data on each stratum and sub-stratum corresponding to the standard well T10, as well as well completion logging data, were obtained. Well inclination, azimuth, and natural gamma ray curve data of the drilling well were also obtained. Seismic databases around the drilling well T12 and the standard well were also obtained.

[0052] 2) Using existing standard well completion logging curves, the stratigraphic interfaces of each stratum on the seismic body are determined through calibration on seismic data, and the dip angle and dip direction of each stratum are determined:

[0053] Using the completion logging curve of standard well T10 calibrated in the seismic database, the corresponding stratigraphic boundaries of each region are traced in the seismic database according to the stratigraphic boundary values ​​of well T10. This embodiment takes the real-time formation tracking of the high-angle well T12, drilled in formation A, as an example. Figure 2As shown, with the overlying stratum M accurately determined, the dip angle of stratum A was obtained as 13° and the dip direction of stratum A was south-southeast, specifically 160°, by measuring the attitude of stratum A in the seismic body. Due to the limitation of seismic data resolution, only the interface location of stratum A could be determined, but the interface locations of each sub-stratum within stratum A could not be determined. Therefore, the interface of the favorable sub-strata A1 and A4 encountered by the standard well T10 could not be accurately determined seismically.

[0054] 3) Determine the stratigraphic affiliation of the drilling site by calibrating the real-time drilling trajectory on seismic data, and determine the intersection relationship between the real-time drilling trajectory and each stratigraphic unit:

[0055] Using the real-time trajectory calibration of the T12 well in the drilling process on seismic data, attached Figure 2 To compile well trajectories and formation distribution maps of the standard well T10 and the main drilling well T12 in the Tongnanba gas field using the real-time formation tracking method for high-angle wells of this invention, determined by seismic calibration, it was determined from the maps that the main drilling well T12 is currently traversing formation A. Based on the real-time trajectory of the main drilling well T12, its interaction with the formation was determined to be a bedding-parallel interaction. A bedding-parallel interaction occurs when the azimuth of the well trajectory is the same as the dip direction of the formation. In a bedding-parallel interaction, the thickness of the true formation encountered in the formation is significantly less than the vertical thickness corrected according to the wellbore trajectory inclination and azimuth. In contrast, a reverse bedding-parallel interaction occurs when the azimuth of the well trajectory is opposite to the dip direction of the formation. In a reverse bedding-parallel interaction, the thickness of the true formation encountered in the formation is significantly greater than the vertical thickness corrected according to the wellbore trajectory inclination and azimuth.

[0056] 4) Construct depth correction processing models for logging-while-drilling curves under different intersection relationships between the real-time drilling trajectory and the formation. Based on the intersection relationship between the real-time drilling trajectory and each formation, select the corresponding depth correction processing model for the logging-while-drilling curves and perform depth correction processing to determine the corrected logging-while-drilling curves.

[0057] Based on the intersection relationship between the real-time trajectory of the drilling operation and the formations determined in step 3), a theoretical model for depth correction under different intersection relationships between the drilling operation and the formations is established. Figure 3 The attached diagram illustrates the theoretical model of depth correction under different junctions between the wellbore and the formation, compiled using the real-time formation tracking method for high-angle wells according to this invention. Figure 3In the diagram, the dashed surface EIJK represents the attitude of the drilled formation, EG represents the actual drilled formation thickness along the well trajectory, EF represents the vertical formation thickness, and the length of EI is the true formation thickness. Here, the actual drilled formation thickness EG is known through the drilling trajectory, and the real-time well inclination, azimuth, and natural gamma ray logging curves of the drilling well are obtained through step 1). The dip angle and dip direction of the formation are determined through step 2), and the intersection relationship between the real-time drilling trajectory and each formation is determined through step 3). Based on these known data, the calculation model for the true formation thickness EI can be derived. Therefore, the depth correction processing model for the logging curves of each depth sampling interval within the drilling well is calculated sequentially from top to bottom as follows:

[0058]

[0059] In equation (1), D C1 D is the corrected depth of the first depth sampling point. C(i+1) D is the corrected depth of the (i+1)th depth sampling point. A1 D represents the original depth of the first depth sampling point. Ai Let D be the original depth of the i-th depth sampling point. A(i+1) α is the original depth of the (i+1)th depth sampling point, all in meters; i is the sampling point number, an integer starting from 1; α is the dip angle of the formation, in degrees; β is the dip direction of the formation, in degrees; θ is the inclination angle of the drilling, in degrees; γ is the azimuth angle of the drilling, in degrees; when the intersection relationship between the real-time trajectory of the drilling and each formation is in-stratum intersection, the “±” in equation (1) is taken as “-”; when the intersection relationship between the real-time trajectory of the drilling and each formation is in-stratum intersection, the “±” in equation (1) is taken as “+”.

[0060] Since the well trajectory of the T12 well and the formation A are connected in the same direction, the "±" in formula (1) is replaced with "-". The corrected depths corresponding to the original depths of each sampling point of the T12 well gamma logging curve are calculated in sequence. The corrected depths corresponding to the original depths of each sampling point of the gamma logging curve are then used to determine the corrected natural gamma logging curve.

[0061] 5) In the formations encountered by the real-time drilling trajectory, compare the logging-while-drilling curves after drilling correction with the completion logging curves of existing standard wells to determine whether the real-time drilling trajectory has entered the predetermined subdivided formations or sweet spots, and optimize the well trajectory in a timely manner until drilling is completed.

[0062] Figure 4The natural gamma ray curve (WWW) of well T12 in the Tongnanba gas field was obtained after conventional depth vertical correction. Since T12 and formation A are typical bedding junctions, applying depth vertical correction significantly elongates the WWW curve. Comparison with the WWW curve of the standard well T10 in formation A revealed that, for the same or approximately the same thickness from the top of formation A, the curve shapes did not correspond. This led to errors in the subdivided formation attribution of the analyzed well, resulting in inaccuracies in determining subdivided formations when comparing the WWW curve after depth vertical correction with the standard well T10.

[0063] Appendix Figure 5 This diagram illustrates the comparison between the natural gamma ray curve of well T12 in the Tongnanba Gas Field after depth correction and the standard well T10, compiled using the real-time formation tracking method for high-angle wells of this invention. The diagram shows a good correlation between the corrected natural gamma ray curve of well T12 and the natural gamma ray curve of the standard well T10. Based on the natural gamma ray standard layers of each subdivided formation, the subdivided formations A1, A2, A3, and A4 of well T12 were determined. The second line in the diagram shows that the results of the subdivided formations indicate that well T12 has entered the designed target formation, which is subdivided formation A4 in formation A. This indicates that well T12 has been successfully drilled according to the predetermined goal and does not require adjustment of the well trajectory. The next step is to continue data tracking and processing until well T12 is completed.

[0064] Example 2

[0065] The real-time formation tracking device for high-angle wells in this embodiment includes the following functional modules:

[0066] Data acquisition module: Acquires data on all strata and sub-strata of existing standard wells around the drilling well, as well as well completion logging data, real-time well inclination, azimuth, logging-while-drilling curves of the drilling well, and seismic data around the drilling well.

[0067] Module for determining the interface and attitude of each stratum: Using existing standard well completion logging curves on seismic data, the interface of each stratum on the seismic body is determined, and the dip angle and dip direction of each stratum are determined;

[0068] The module for determining the intersection relationship between the real-time trajectory of the drilling well and the formation: It uses the calibration of the real-time trajectory of the drilling well on seismic data to determine the formation at the location of the drilling well and to determine the intersection relationship between the real-time trajectory of the drilling well and each formation.

[0069] The logging-while-drilling curve depth correction processing module: Constructs a logging-while-drilling curve depth correction processing model under different intersection relationships between the real-time trajectory of the drilling and the formation, performs depth correction processing on the logging-while-drilling curve based on the logging-while-drilling curve depth correction processing model, and determines the corrected logging-while-drilling curve.

[0070] Formation comparison module: In the formations encountered by the real-time trajectory of the drilling operation, the logging-while-drilling curves after drilling correction are compared with the completion logging curves of existing standard wells to determine whether the real-time trajectory of the drilling operation has entered the predetermined subdivided formations or sweet spots.

[0071] The above functional modules form a functional module architecture, thereby realizing the real-time formation tracking method for high-angle wells during drilling in Example 1.

Claims

1. A method for real-time formation tracking while drilling in highly deviated wells, characterized in that, Includes the following steps: (1) Obtain data on all strata and sub-strata of existing standard wells around the drilling well, as well as well completion logging data, real-time well inclination, azimuth, logging-while-drilling curves of the drilling well, and seismic data around the drilling well. (2) Using the calibration of existing standard well completion logging curves on seismic data, determine the stratigraphic interfaces of each stratum on the seismic body, and determine the dip angle and dip direction of each stratum; (3) The stratigraphic affiliation of the location of the drilling well is determined by the calibration of the real-time trajectory of the drilling well on the seismic data, and the intersection relationship between the real-time trajectory of the drilling well and each stratigraphic unit is determined; the intersection relationship includes in-stratum intersection and reverse-stratum intersection. (4) Construct a depth correction processing model for logging-while-drilling curves under different intersection relationships between the real-time trajectory of the drilling and the formation, carry out depth correction processing of the logging-while-drilling curves according to the logging-while-drilling curve depth correction processing model, and determine the corrected logging-while-drilling curves. The logging-while-drilling curve depth correction processing model is as follows: （1） In equation (1), D C1 D is the corrected depth of the first depth sampling point. C(i+1) D is the corrected depth of the (i+1)th depth sampling point. A1 D represents the original depth of the first depth sampling point. Ai Let D be the original depth of the i-th depth sampling point. A(i+1) α is the original depth of the (i+1)th depth sampling point; i is the sampling point number, which is an integer starting from 1; α is the dip angle of the formation; β is the dip direction of the formation; θ is the inclination angle of the drilling; γ is the azimuth angle of the drilling; when the intersection relationship between the real-time trajectory of the drilling and each formation is in-layer intersection, the "±" in Equation (1) is taken as "-"; when the intersection relationship between the real-time trajectory of the drilling and each formation is in-layer intersection, the "±" in Equation (1) is taken as "+". (5) In the formations encountered by the real-time trajectory of the drilling, the logging-while-drilling curve after the drilling correction is compared with the completion logging curve of the existing standard well to determine whether the real-time trajectory of the drilling has entered the predetermined subdivided formation or sweet spot.

2. The method for real-time formation tracking while drilling in highly deviated wells as described in claim 1, characterized in that, D C1 D C(i+1) D A1 D Ai D A(i+1) The unit for all of them is m.

3. The method for real-time formation tracking while drilling in highly deviated wells as described in claim 1 or 2, characterized in that, The units for α, β, θ, and γ are all °.

4. A real-time formation tracking device for high-angle wells during drilling, characterized in that, Includes the following functional modules: Data acquisition module: Acquires data on all strata and sub-strata of existing standard wells around the drilling well, as well as well completion logging data, real-time well inclination, azimuth, logging-while-drilling curves of the drilling well, and seismic data around the drilling well. Module for determining the interface and attitude of each stratum: Using existing standard well completion logging curves on seismic data, the interface of each stratum on the seismic body is determined, and the dip angle and dip direction of each stratum are determined; The module for determining the intersection relationship between the real-time trajectory of the drilling well and the formation: It uses the calibration of the real-time trajectory of the drilling well on seismic data to determine the formation at the location of the drilling well, and determines the intersection relationship between the real-time trajectory of the drilling well and each formation; the intersection relationship includes in-stratum intersection and reverse-stratum intersection; The logging-while-drilling (LWD) curve depth correction processing module: This module constructs a LWD curve depth correction processing model under different intersection relationships between the real-time drilling trajectory and the formation. Based on this model, it performs depth correction processing on the LWD curves to determine the corrected LWD curves. The LWD curve depth correction processing model is as follows: （1） In equation (1), D C1 D is the corrected depth of the first depth sampling point. C(i+1) D is the corrected depth of the (i+1)th depth sampling point. A1 D represents the original depth of the first depth sampling point. Ai Let D be the original depth of the i-th depth sampling point. A(i+1) α is the original depth of the (i+1)th depth sampling point; i is the sampling point number, which is an integer starting from 1; α is the dip angle of the formation; β is the dip direction of the formation; θ is the inclination angle of the drilling; γ is the azimuth angle of the drilling; when the intersection relationship between the real-time trajectory of the drilling and each formation is in-layer intersection, the "±" in Equation (1) is taken as "-"; when the intersection relationship between the real-time trajectory of the drilling and each formation is in-layer intersection, the "±" in Equation (1) is taken as "+". Formation comparison module: In the formations encountered by the real-time trajectory of the drilling operation, the logging-while-drilling curves after drilling correction are compared with the completion logging curves of existing standard wells to determine whether the real-time trajectory of the drilling operation has entered the predetermined subdivided formations or sweet spots.

5. The real-time formation tracking device for high-angle wells as described in claim 4, characterized in that, D C1 D C(i+1) D A1 D Ai D A(i+1) The unit for all of them is m.

6. The real-time formation tracking device for high-angle wells as described in claim 4 or 5, characterized in that, The units for α, β, θ, and γ are all °.

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