Directional well guiding method based on dynamic lithologic profile

Abstract

The invention discloses a directional well guiding method based on a dynamic lithologic profile, and relates to the technical field of oil-gas exploration. According to the technical scheme, before entering a horizontal section of a directional well, a time domain lithologic section 0 is converted into a depth domain lithologic section 0 through an initial velocity field 0; calibrating a time-depth relationship of a pilot well, generating a well point speed, adding a speed body, performing smooth correction to obtain a speed body 1, forming a new depth domain lithologic section 1, and loading a design track; the while-drilling sound wave data is converted into the speed and then loaded to the speed body 1, and the current speed field and the X-length speed field are compared and corrected to obtain a speed field 2; converting the time domain lithologic section 0 into a depth domain lithologic section 2 by using a velocity field 2, and loading the actual drilling depth; and comparing the track positions of the two sections to obtain an error delta D, adjusting the length track of the drilling direction Y according to the delta D, and returning the adjustment scheme if necessary. The method has the beneficial effects that the drilling precision and efficiency are remarkably improved, the limitation of the prior art is overcome, real-time dynamic adjustment is achieved, resource exploration and development benefits are improved, and the innovation and development of the drilling technology are promoted.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas exploration technology and relates to a directional well guidance method based on dynamic lithological profiles. Background Technology

[0002] Both risk exploration and conventional preliminary exploration are moving towards greater efficiency, with target formations becoming increasingly thinner. Directional drilling technology is a crucial application method in this process. For example, Chinese patent application CN118065879A discloses a method for real-time measurement and control of wellbore curvature in directional drilling. Current directional drilling techniques fall into two categories: curve fitting and seismic cross-section. Curve fitting uses the actual drilled formation curve (GR, resistivity, etc.) and the pilot well's formation curve to fit the formation dip angle, guiding the drilling direction. This method can only fit a small segment of the formation dip angle and becomes ineffective in the event of a small fault or a sudden change in formation velocity. Another method uses 3D seismic cross-sections, loading well trajectory data from the field into a 3D seismic profile. By comparing this with the designed trajectory and the seismic phase axis, the subsequent trajectory direction is determined. This method, based on the seismic phase axis, is insufficiently accurate if the effective reservoir thickness is only 5-10m, using a 30-50m phase axis for control. Furthermore, if there is a sudden change in formation velocity while the previous seismic profile is still used for guidance, significant errors will occur, rendering the method meaningless. Both directional drilling methods have significant limitations in addressing the issues of velocity anomalies and thin reservoirs in certain regions and formations. How to accurately directional drill in thin reservoirs and formations with velocity anomalies has become an urgent problem to be solved. Summary of the Invention

[0003] To address the aforementioned technical problems in existing technologies, this invention provides a directional well guidance method based on dynamic lithological profiles. Through a remote data transmission system, it tracks formation velocity and reservoir dynamic changes in real time, with millisecond-level delays and centimeter-level errors, and synchronously and dynamically adjusts trajectory data based on the lithological profile in the depth domain, ensuring that the drill bit always drills stably along the target formation.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A directional well steering method based on dynamic lithological profiles, comprising the following steps:

[0006] S1. Before entering the starting point of the horizontal section of the directional well, the time domain lithological profile 0 of the well trajectory is converted into the depth domain lithological profile 0 through the initial velocity field 0.

[0007] S2. Calibrate the time-depth relationship of the pilot hole, generate the velocity at the well point, add this data to the velocity volume, perform local smoothing correction, obtain velocity volume 1, form a new depth domain lithological profile 1, and load the design trajectory at the same time.

[0008] S3. The received acoustic data while drilling is converted into velocity and loaded into velocity body 1 for comparison. The current velocity field and the velocity field along the X length of the drilling direction are corrected, and local smoothing correction is performed to form the corrected velocity field 2.

[0009] S4. Using the corrected velocity field 2, the same time domain lithological profile 0 is converted into depth domain lithological profile 2, while the current actual drilling depth is loaded.

[0010] S5. Compare the trajectory positions of the current actual drilling point X on the lithological profile 1 and the lithological profile 2 in the depth domain to form error data ΔD.

[0011] Furthermore, in step S1, before entering the starting point of the horizontal section of the directional well, the time-domain lithological profile 0 of the well trajectory is converted into the depth-domain lithological profile 0 through the initial velocity field 0 by the velocity module of the interpretation software.

[0012] Furthermore, in step S2, the time-depth relationship of the pilot hole is accurately calibrated using the synthetic recording module, the velocity at the well point is generated, the data is added to the velocity volume, local smoothing correction is performed, and velocity volume 1 is obtained. A new depth domain lithological profile 1 is formed by the velocity module of the interpretation software, and the design trajectory is loaded at the same time.

[0013] Furthermore, in step S3, after receiving the sonic data while drilling, the seismic interpretation software converts it into velocity and loads it into velocity volume 1 for comparison. It then corrects the current velocity field and the velocity field along the X-length of the drilling direction, performs local smoothing correction, and forms the corrected velocity field 2.

[0014] Furthermore, in step S3, X is 10m, 20m, or 30m.

[0015] Furthermore, in step S4, the same time-domain lithological profile 0 is converted into depth-domain lithological profile 2 using the velocity module of the interpretation software through the corrected velocity field 2, while the current actual drilling depth is loaded.

[0016] Furthermore, in step S5, Y is 10m, 20m, or 30m.

[0017] Furthermore, it also includes remote data transmission systems for receiving, processing, and feeding back data.

[0018] Furthermore, in step S5, the trajectory of the next target point and the Y-direction drilling direction is corrected.

[0019] Furthermore, if ΔD < 20cm, no adjustment is needed as it does not affect drilling; if ΔD > 20cm, an adjustment plan is formulated and transmitted back to the well site.

[0020] The beneficial effects of this invention are:

[0021] Compared with existing technologies, this method links on-site drilling data with dynamic lithological profiles through a remote data transmission system. The two interact cyclically, forming a positive feedback loop, ultimately enabling the drill bit to drill stably in the target formation based on the dynamic depth-domain lithological profile. The directional well guidance method based on dynamic lithological profiles described in this invention also has the following technical features or beneficial effects:

[0022] (1) Significantly Improved Drilling Accuracy and Efficiency: With risk exploration and conventional preliminary exploration increasingly focused on profitability, target formations are becoming thinner, thus increasing the demands on drilling accuracy. This invention introduces dynamic lithological profiling technology, enabling real-time tracking of formation velocity and reservoir dynamics, and trajectory adjustments with millisecond-level delays and centimeter-level errors. This not only significantly improves drilling accuracy but also ensures the drill bit consistently drills along the target formation, thereby greatly enhancing drilling efficiency.

[0023] (2) Overcoming the limitations of existing technologies: Current directional drilling technologies, such as curve fitting and 3D seismic cross-sectioning, have significant limitations when dealing with velocity anomalies and thin reservoirs. Curve fitting can only fit a small segment of formation dip angle and becomes ineffective when encountering small faults or sudden changes in formation velocity; while 3D seismic cross-sectioning is difficult to achieve precise guidance in thin reservoirs due to insufficient accuracy in phase axis control. This invention effectively overcomes these limitations by dynamically adjusting trajectory data, providing a possibility for achieving precise directional drilling under complex geological conditions.

[0024] (3) Real-time dynamic adjustment: This invention utilizes a remote data transmission system to receive, process, and provide feedback on drilling data in real time. By comparing the trajectory positions of the current drilled point with the lithological profile in the depth domain, error data is generated, and the trajectory of the next target point and drilling direction is corrected accordingly. This real-time dynamic adjustment capability makes the drilling process more flexible and controllable, helps to promptly detect and correct deviations, and ensures the smooth progress of drilling operations.

[0025] (4) Enhancing the efficiency of resource exploration and development: With the continuous deepening of oil and gas exploration and development, resource exploration and development under complex geological conditions has become a new challenge. This invention provides a high-precision directional well steering method, which helps to discover and exploit more oil and gas resources in thin reservoirs and formations with abnormal velocity, thereby enhancing the efficiency of resource exploration and development.

[0026] (5) Promoting the innovation and development of drilling technology: The proposal and implementation of this invention not only solves the current problems faced by directional drilling technology, but also provides new ideas and methods for the innovation and development of drilling technology. By introducing dynamic lithological profiling technology and remote data transmission system, the intelligent and automated drilling process is realized, laying a solid foundation for the future development of drilling technology.

[0027] In summary, the directional well steering method based on dynamic lithological profiles of this invention has shown significant beneficial effects in improving drilling accuracy and efficiency, overcoming the limitations of existing technologies, achieving real-time dynamic adjustment, enhancing the benefits of resource exploration and development, and promoting drilling technology innovation and development. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0029] Figure 1 This is a flowchart of the technology of this invention;

[0030] Figure 2 This is a schematic diagram of the actual operation of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The following description, in conjunction with the accompanying drawings... Figure 1-2 The method for guiding directional wells based on dynamic lithological profiles is further explained, and the technical solutions in the embodiments of this application are clearly and completely described. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0032] Example 1

[0033] This invention proposes a directional well guidance method that combines time-domain and depth-domain profiles. Based on a high-resolution time-domain lithology profile, the velocity field is converted into a depth-domain lithology profile. The well velocity is then used for secondary correction to form the depth-domain lithology profile. During drilling, the actual drilling depth data is transmitted back in real time and compared with the designed trajectory to form error data ΔD. This data is used to correct the velocity field within a certain range of the current position and the direction of advance, forming a dynamic depth-domain lithology profile, and the actual drilling trajectory direction is adjusted synchronously.

[0034] Unlike traditional posterior methods that rely solely on time domain or curve fitting, this invention proposes a method for real-time dynamic adjustment of lithological profiles in the depth domain, which yields immediate results.

[0035] Specific implementation plan:

[0036] Required data and software: 1. High-resolution lithological inversion data (vertical resolution 1-3m, preferably sufficient to identify the target layer), velocity field data, and pilot well data; 2. Directional well design data; 3. Seismic interpretation software; 4. Well site data remote transmission software; 5. Data conversion module (interface) for data exchange between the remote transmission software and the seismic software.

[0037] Implementation steps:

[0038] 1. Before entering point A (the starting point of the horizontal section) of the directional well, the time domain lithological profile 0 of the well trajectory is converted into the depth domain lithological profile 0 through the initial velocity field 0 using the velocity module of the interpretation software;

[0039] 2. Use the synthetic recording module to accurately calibrate the time-depth relationship of the pilot hole, generate the velocity at the well point, add this data to the velocity volume, perform local smoothing correction, and obtain velocity volume 1. Use the velocity module of the interpretation software to form a new depth domain lithological profile 1, and load the design trajectory at the same time.

[0040] 3. After receiving the sonic data while drilling, the seismic interpretation software converts it into velocity and loads it into velocity volume 1. It then compares and corrects the velocity field at the current location and 10m (or 20m, 30m, based on the length of a single drill pipe and the drilling speed) in the drilling direction. It performs local smoothing correction to form the corrected velocity field 2.

[0041] 4. Using the corrected velocity field 2, the velocity module of the interpretation software converts the same time-domain lithological profile 0 into the depth-domain lithological profile 2, while loading the current actual drilling depth;

[0042] 5. Compare the trajectory positions of the current actual drilling point X on the lithological profile 1 and the lithological profile 2 in the depth domain to form error data ΔD. Correct the trajectory of the next target point and the drilling direction 10m (or 20m, 30m, based on the length of a single drill pipe and the drilling speed): If ΔD is 0 or very small and does not affect drilling, no adjustment is needed; if ΔD is large, an adjustment plan is formed and transmitted back to the well site.

[0043] Note: In extreme cases, the adjustment interval is calculated based on a single drill rod of 10m. At this time, the drilling time is 30-60 minutes / meter (equivalent to 18-36 seconds / cm), the data transmission interval is 2 seconds, the trajectory error calculation and dynamic profile adjustment are 2 seconds, and the upload and download delay is 1 second, with a total time of about 7 seconds, not exceeding 10 seconds, which can meet the adjustment accuracy requirements.

[0044] Example 2

[0045] This is either a new embodiment or a supplement to Embodiment 1.

[0046] This invention proposes a directional well guidance method that combines time-domain and depth-domain profiles, aiming to achieve real-time dynamic adjustments during the drilling process. By combining high-resolution time-domain lithology profiles with velocity fields, a dynamic depth-domain lithology profile is formed, thereby enabling precise control of the drill bit position. This method not only improves drilling accuracy but also significantly enhances the flexibility and controllability of drilling operations.

[0047] Before drilling operations begin, high-resolution lithology inversion data, velocity field data, and pilot well data are used to convert the time-domain lithology profile into a depth-domain lithology profile using the velocity module of seismic interpretation software. Subsequently, the time-depth relationship of the pilot well is precisely calibrated using the synthetic record module, the velocity at the well point is generated, and this velocity is added to the velocity volume. Local smoothing corrections are then performed to form a new depth-domain lithology profile, and the designed trajectory is loaded.

[0048] During drilling, the seismic interpretation software receives real-time acoustic data while drilling, converts it into velocity data, and loads it into the velocity volume. By comparing the current velocity field with the velocity field within a certain range along the drilling direction, local smoothing correction is performed to form a corrected velocity field. Then, using the corrected velocity field, the lithological profile in the same time domain is converted into a lithological profile in the depth domain, and the current actual drilling depth is loaded.

[0049] Next, the trajectory positions of the current drilled point in depth domain lithological profile 1 and depth domain lithological profile 2 are compared to generate error data ΔD. Based on the error data ΔD, the trajectory of the next target point and the drilling direction is corrected. If the error is very small and does not affect drilling, no adjustment is needed; if the error is large, an adjustment plan is generated and transmitted back to the well site via well site data remote transmission software to guide drilling operations. The error is ±20cm.

[0050] The core principle of this invention lies in combining high-resolution time-domain lithological profiles with velocity fields to form dynamic depth-domain lithological profiles. By receiving real-time drilling acoustic data and converting it into velocity data, which is then loaded into the velocity volume, real-time correction of the velocity field is achieved. Then, the corrected velocity field is used to convert the time-domain lithological profile into a depth-domain lithological profile, thereby enabling precise control of the drill bit position.

[0051] Compared to traditional posterior methods relying solely on time-domain analysis or curve fitting, the real-time dynamic adjustment of depth-domain lithological profiles proposed in this invention offers significant advantages. First, this method can receive and process drilling data in real time, immediately correcting the trajectory after error data is generated, resulting in immediate and effective results. Second, the combination of high-resolution time-domain lithological profiles and velocity fields improves drilling accuracy and controllability. Finally, this method also enhances the flexibility and adaptability of drilling operations, enabling it to address drilling challenges under complex geological conditions.

[0052] In summary, the directional well guidance method combining time-domain and depth-domain profiles proposed in this invention demonstrates significant advantages in terms of functionality, working process, principle, and effectiveness. This method not only improves drilling accuracy and efficiency but also provides a new solution for drilling operations under complex geological conditions.

[0053] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A directional well steering method based on dynamic lithological profiles, characterized in that, The steps are as follows: S1. Before entering the starting point of the horizontal section of the directional well, the time domain lithological profile 0 of the well trajectory is converted into the depth domain lithological profile 0 through the initial velocity field 0. S2. Calibrate the time-depth relationship of the pilot hole, generate the velocity at the well point, add this data to the velocity volume, perform local smoothing correction, obtain velocity volume 1, form a new depth domain lithological profile 1, and load the design trajectory at the same time. S3. The received acoustic data while drilling is converted into velocity and loaded into velocity body 1 for comparison. The current velocity field and the velocity field along the X length of the drilling direction are corrected, and local smoothing correction is performed to form the corrected velocity field 2. S4. Using the corrected velocity field 2, the same time domain lithological profile 0 is converted into depth domain lithological profile 2, while the current actual drilling depth is loaded. S5. Compare the trajectory positions of the current actual drilling point X on the lithological profile 1 and the lithological profile 2 in the depth domain to form error data ΔD.

2. The directional well guidance method based on dynamic lithological profiles as described in claim 1, characterized in that, In step S1, before entering the starting point of the horizontal section of the directional well, the time domain lithological profile 0 of the well trajectory is converted into the depth domain lithological profile 0 through the initial velocity field 0 by the velocity module of the interpretation software.

3. The directional well guidance method based on dynamic lithological profiles as described in claim 1, characterized in that, In step S2, the time-depth relationship of the pilot hole is accurately calibrated using the synthetic recording module, the velocity at the well point is generated, the data is added to the velocity volume, local smoothing correction is performed, and velocity volume 1 is obtained. A new depth domain lithology profile 1 is formed by the velocity module of the interpretation software, and the design trajectory is loaded at the same time.

4. The directional well steering method based on dynamic lithological profiles as described in claim 1, characterized in that, In step S3, after receiving the sonic data while drilling, the seismic interpretation software converts it into velocity and loads it into velocity volume 1 for comparison. It then corrects the current velocity field and the velocity field along the X-length of the drilling direction, performs local smoothing correction, and forms the corrected velocity field 2.

5. The directional well guidance method based on dynamic lithological profiles as described in any one of claims 1-4, characterized in that, In step S3, X is 10m, 20m, or 30m.

6. The directional well steering method based on dynamic lithological profiles as described in claim 1, characterized in that, In step S4, the corrected velocity field 2 is used to convert the same time domain lithological profile 0 into the depth domain lithological profile 2 using the velocity module of the interpretation software, while loading the current actual drilling depth.

7. The directional well steering method based on dynamic lithological profiles as described in claim 1, characterized in that, In step S5, Y is 10m, 20m, or 30m.

8. The directional well guidance method based on dynamic lithological profiles as described in any one of claims 1-4, 6, and 7, characterized in that, It also includes remote data transmission systems for receiving, processing, and feeding back data.

9. The directional well guidance method based on dynamic lithological profiles as described in any one of claims 1-4, 6, and 7, characterized in that, In step S5, the trajectory of the next target point and the Y-direction drilling direction is corrected.

10. The directional well guidance method based on dynamic lithological profiles as described in claim 9, characterized in that, If ΔD < 20cm, no adjustment is needed as it does not affect drilling; if ΔD > 20cm, an adjustment plan is formulated and transmitted back to the well site.

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