Method and apparatus for determining wellbore configuration based on geologic risk

Abstract

The application discloses a method and device for determining well structure based on geological risk, and relates to the technical field of drilling engineering. The method comprises the following steps: based on the complex formation-drilled depth relation diagram of adjacent wells, the target well-adjacent well seismic profile and the target well-adjacent well well logging interpretation profile, a three-dimensional comparison diagram of the target well and the adjacent well in different depth domains is constructed; according to the seismic characteristics, the well logging characteristics and the drilled characteristics of the target well and the adjacent well in different depth domains, the probability distribution of the complex formation existing in the target well in different depth domains is determined; according to the probability distribution, the initial evaluation risk points and the initial evaluation points to be sealed of the target well are determined; the initial evaluation risk points and the initial evaluation points to be sealed are respectively reduced by using the preset optimization process of different complex formations, so that the final selected points to be sealed and the final selected risk points of the target well are obtained; and according to the final selected points to be sealed and the final selected risk points, casing design is carried out, and the well structure of the target well is determined. The application is used for improving the safety and economy of the well depth structure design.

Description

Technical Field

[0001] This application relates to the field of drilling engineering technology, and in particular to a method and apparatus for determining wellbore structure based on geological risk. Background Technology

[0002] In the field of drilling engineering, wellbore structure design is a crucial aspect of ensuring the safe and efficient conduct of drilling operations. With increasing energy demands and technological advancements, drilling activities are increasingly extending to deeper formations with more complex geological conditions. These complex formations include, but are not limited to, high-pressure brine layers, easily lost circulation zones, collapse zones, and oil and gas reservoirs, posing numerous challenges to drilling operations, such as wellbore stability issues, insufficient casing strength, and low drilling efficiency.

[0003] Currently, most design methods in existing technologies rely on empirical geological judgments and simple formation pressure estimations. However, this approach lacks precise analysis of detailed formation characteristics and potential risks, leading to insufficient understanding of formation heterogeneity and the complexity of geological structures. Especially when dealing with complex formations, such as high-porosity formations prone to well leakage, shale formations prone to collapse, high-pressure brine layers, and oil and gas layers, it is often impossible to comprehensively and accurately assess the potential geological risks of deeper and more complex formations, resulting in poor safety and economy in wellbore structure design. Summary of the Invention

[0004] In view of the above problems, this application provides a method, apparatus, storage medium and computer program product for determining wellbore structure based on geological risk. The main purpose is to comprehensively and accurately assess the potential geological risks of deeper strata with more complex geological conditions, so as to improve the safety and economy of wellbore structure design.

[0005] To address the aforementioned technical problems, the first aspect of this application provides a method for determining wellbore structure based on geological risk, the method comprising:

[0006] Based on the complex formation-drilling depth relationship map of adjacent wells, the seismic profile of the target well-adjacent wells, and the logging interpretation profile of the target well-adjacent wells, a three-dimensional comparison map of the target well and adjacent wells in different depth domains is constructed. The three-dimensional comparison map includes the seismic characteristics, logging characteristics, and drilling characteristics of the target well and adjacent wells in different depth domains. The complex formation includes at least one of the following: well leakage layer, collapse layer, brine layer, and oil and gas layer.

[0007] Based on the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and adjacent wells in different depth domains, the probability distribution of complex formations existing in the target well in different depth domains is determined.

[0008] Based on the probability distribution of complex formations in different depth domains of the target well, determine the initial risk points and the initial sealing points corresponding to the target well;

[0009] By using optimized processes preset for different complex formations, the initial assessment must-sealing points and initial assessment risk points are reduced to obtain the final selection must-sealing points and final selection risk points corresponding to the target well;

[0010] Based on the final selection of the mandatory sealing point and the final selection of the risk point, the casing design of the target well is carried out to determine the wellbore structure of the target well.

[0011] In this embodiment of the application, before constructing a three-dimensional comparison map of the target well and the adjacent well in different depth domains based on the complex formation-actual drilling depth relationship map of the adjacent well, the seismic profile of the target well-adjacent well, and the logging interpretation profile of the target well-adjacent well, the method further includes: constructing a complex formation-actual drilling depth relationship map of the adjacent well based on the complex formation and actual drilling depth of the complex formation corresponding to the adjacent well in the target area; constructing a seismic profile of the target well-adjacent well based on the original seismic data corresponding to the target well and the adjacent well, and constructing a seismic profile of the target well-adjacent well and a logging interpretation profile of the target well-adjacent well based on the original logging data corresponding to the target well and the adjacent well, respectively. The original logging data includes at least three of the following: sonic transit time, formation density, wellbore curve, and resistivity parameters.

[0012] In this embodiment of the application, the probability distribution of complex formations in different depth domains of the target well is determined based on the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and adjacent wells in different depth domains. This includes: calculating the feature similarity between the target well and adjacent wells in different depth domains based on the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and adjacent wells in different depth domains; and determining the probability distribution of complex formations in different depth domains of the target well based on the feature similarity between the target well and adjacent wells in different depth domains.

[0013] In this embodiment of the application, the preliminary risk points and preliminary sealing points of the target well are determined according to the probability distribution of the existence of complex formations in different depth domains of the target well. This includes: taking the depth points in the probability distribution of the existence of complex formations in different depth domains of the target well that exceed the first probability but do not exceed the second probability as the preliminary risk points, where the first probability is less than the second probability; and taking the depth points in the probability distribution of the existence of complex formations in different depth domains of the target well that exceed the second probability as the preliminary sealing points.

[0014] In this embodiment, different optimization processes for complex formations are used to reduce the initial risk points and initial mandatory sealing points to obtain the final mandatory sealing points and final risk points corresponding to the target well. This includes: selecting a target risk point from the initial mandatory sealing points and initial risk points, and determining the target complex formation corresponding to the target risk point; obtaining the optimization results of the preset optimization process for the target complex formation in adjacent wells for the key parameters of the target layer, and correcting the key parameters of the target layer in the target well based on the optimization results to obtain the corrected key parameters of the target layer corresponding to the target complex formation, where the key parameters are the performance parameters targeted by the optimization process; determining the upper and lower adjacent layers corresponding to the target complex formation, and obtaining the upper and lower adjacent layer key parameters for each of the upper and lower adjacent layers respectively; determining whether the differences between the corrected key parameters of the target layer and the key parameters of the upper and lower adjacent layers are all within a preset range; if yes, the target risk point is reduced; if not, the target risk point is retained, and determined as a final mandatory sealing point or a final risk point based on the type label of the target risk point.

[0015] In this embodiment, the casing design for the target well is performed based on the final selection of mandatory sealing points and final selection of risk points to determine the wellbore structure. This includes: determining the number of casing openings for the target well based on the number of risk points corresponding to the final selection of mandatory sealing points and final selection of risk points; designing the casing for the depth segment corresponding to each casing opening to obtain casing structure parameters, including the casing material, wall thickness, steel grade, and connection method; conducting an evaluation of the casing structure parameters based on the target well to obtain evaluation results, including feasibility indicators and safety indicators; if the feasibility indicators and safety indicators do not both meet their respective preset standards, the casing structure parameters are iteratively adjusted so that the feasibility indicators and safety indicators corresponding to the new casing structure parameters both meet their respective preset standards; if the feasibility indicators and safety indicators both meet their respective preset standards, the casing structure parameters are used as the wellbore structure.

[0016] In this embodiment of the application, before using the preset optimization process of different complex formations to reduce the initial assessment must-sealing points and initial assessment risk points to obtain the final selection must-sealing points and final selection risk points corresponding to the target well, the method further includes: optimizing the wellbore trajectory of the target well based on the initial assessment must-sealing points and initial assessment risk points to reduce the initial assessment must-sealing points and initial assessment risk points.

[0017] A second aspect of this application provides an apparatus for determining wellbore structure based on geological risk, the apparatus comprising:

[0018] The first building unit is used to construct a three-dimensional comparison map of the target well and the adjacent well in different depth domains based on the complex formation-drilling depth relationship map of the adjacent well, the seismic profile of the target well and the adjacent well, and the well logging interpretation profile of the target well and the adjacent well. The three-dimensional comparison map includes the seismic characteristics, well logging characteristics and drilling characteristics of the target well and the adjacent well in different depth domains. The complex formation includes at least one of the following: well leakage layer, collapse layer, brine layer and oil and gas layer.

[0019] The first determining unit is used to determine the probability distribution of complex formations in different depth domains of the target well based on the seismic characteristics, logging characteristics and actual drilling characteristics of the target well and adjacent wells in different depth domains.

[0020] The second determining unit is used to determine the initial risk points and initial sealing points of the target well based on the probability distribution of complex formations in different depth domains of the target well.

[0021] The processing unit is used to reduce the initial assessment must-sealing points and initial assessment risk points by using the preset optimization process for different complex strata, so as to obtain the final selection must-sealing points and final selection risk points corresponding to the target well;

[0022] The third determining unit is used to design the casing of the target well based on the final selection of the mandatory sealing point and the final selection of the risk point, and to determine the wellbore structure of the target well.

[0023] A third aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0024] A fourth aspect of this application provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the above-described method.

[0025] The aforementioned technical solution, by combining well logging interpretation data and seismic data from adjacent and target wells, establishes a three-dimensional comparison map containing seismic, well logging, and actual drilling characteristics of the target and adjacent wells at different depth domains. Using this three-dimensional comparison map to comprehensively analyze the seismic, well logging, and actual drilling characteristics of the target and adjacent wells, the existence and probability distribution of complex formations can be more accurately identified, improving the accuracy of geological risk identification for complex formations. By quantitatively analyzing the probability distribution at different depth domains, initial risk points and mandatory sealing points are identified, enabling a more scientific assessment of the likelihood of complex formations. Optimized processes are used to reduce the initial risk points and mandatory sealing points, resulting in final selected risk points and mandatory sealing points. This allows for precise identification of geological risk areas requiring focused attention. Based on the final selected mandatory sealing points and risk points, casing design ensures the safety and economy of the well structure, improves drilling efficiency, and reduces drilling costs. Compared with existing technologies, this application solves the problems of inaccurate geological risk identification and lack of systematic assessment in existing technologies through systematic and quantitative methods, and significantly improves the safety and economy of wellbore structure design when drilling deeper strata with more complex geological conditions.

[0026] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0027] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0028] Figure 1 A flowchart illustrating a method for determining wellbore structure based on geological risk, provided in an embodiment of this application, is shown.

[0029] Figure 2 This paper illustrates a block diagram of a device for determining wellbore structure based on geological risk, as provided in an embodiment of this application. Detailed Implementation

[0030] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0031] Currently, most design methods in existing technologies rely on empirical geological judgments and simple formation pressure estimations. However, this approach lacks precise analysis of detailed formation characteristics and potential risks, leading to insufficient understanding of formation heterogeneity and the complexity of geological structures. Especially when dealing with complex formations, such as high-porosity formations prone to well leakage, shale formations prone to collapse, high-pressure brine layers, and oil and gas layers, it is often impossible to comprehensively and accurately assess the potential geological risks of deeper and more complex formations, resulting in poor safety and economy in wellbore structure design.

[0032] Therefore, this application provides a method for determining wellbore structure based on geological risk. This method can comprehensively and accurately assess the potential geological risks of complex formations, thereby improving the safety and economy of wellbore structure design. The specific implementation steps are as follows: Figure 1 As shown, it includes:

[0033] 101. Based on the complex formation-drilling depth relationship map of adjacent wells, the seismic profile of the target well-adjacent wells, and the well logging interpretation profile of the target well-adjacent wells, construct a three-dimensional comparison map of the target well and adjacent wells in different depth domains.

[0034] The three-dimensional comparison map includes the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and adjacent wells at different depths. The complex formation includes at least one of the following: lost circulation zone, collapse zone, brine zone, and oil and gas zone.

[0035] In this step, geological data of neighboring wells surrounding the target well are collected beforehand, including known complex formations (such as lost circulation zones, collapsed zones, brine layers, and oil and gas layers) and their corresponding actual drilling depths, constructing a complex formation-actual drilling depth relationship map of neighboring wells. Raw seismic data of the target well and neighboring wells are acquired, and a seismic data volume is constructed to obtain a target well-neighboring well seismic profile, which can be achieved using 2D or 3D seismic data to identify formation characteristics at different depths. Raw logging data of the target well and neighboring wells, such as sonic transit time, formation density, wellbore curves, resistivity, etc., are acquired and interpreted in conjunction with the seismic data, constructing a logging interpretation data volume to obtain a target well-neighboring well logging interpretation profile. The aforementioned seismic profile, logging interpretation profile, and complex formation-actual drilling depth relationship map of neighboring wells are integrated into a 3D model. This model should be able to display the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and neighboring wells at different depths, resulting in a 3D comparison map. The locations of all possible complex formations (such as well leakage layers, collapse layers, brine layers, oil and gas layers, etc.) are marked on the 3D comparison map for subsequent analysis.

[0036] 102. Based on the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and adjacent wells in different depth domains, determine the probability distribution of complex formations existing in the target well in different depth domains.

[0037] In this step, the seismic characteristics (such as reflection coefficient, amplitude properties, etc.), logging characteristics (such as sonic transit time, resistivity, etc.), and actual drilling characteristics (such as drilling rate, mud loss, etc.) of the target well and adjacent wells are compared at different depth domains. Statistical methods or machine learning algorithms (such as KNN, SVM, etc.) are used to calculate the similarity between seismic, logging, and actual drilling characteristics at each depth point within different depth domains, generating a feature similarity matrix. Based on the actual drilling experience of adjacent wells and known complex formation information, a baseline is set to assess the probability that the target well may encounter complex formations under the same conditions. Using the data in the feature similarity matrix, combined with the probability of adjacent wells encountering complex formations in the same depth domain, the probability of the target well having complex formations at each depth point is estimated through interpolation or other mathematical methods. Bayesian networks or other probabilistic models can be used to integrate the influence of multiple factors to obtain a more accurate probability distribution. For example, if the feature similarity at a certain depth point is high and adjacent wells have a high frequency of complex formations occurring in the same depth domain, then the target well in that depth domain also has a high probability of having complex formations.

[0038] 103. Determine the initial risk points and initial sealing points corresponding to the target well based on the probability distribution of complex formations in different depth regions.

[0039] In this step, since the probability distribution of complex formations in different depth zones of the target well is known, probability thresholds can be set to distinguish between risk points and mandatory sealing points in different depth zones, thus allowing for more flexible management and response to geological risks. Specifically, a single threshold can be used, setting a fixed probability threshold, such as 50%, to consider all depth points with a probability greater than or equal to 50% as mandatory sealing points in the initial assessment, and those below 50% as risk points in the initial assessment. Alternatively, a dual threshold can be used, setting two fixed probability thresholds, such as 30% and 70%. Depth points below 30% can be considered to have a low probability of complex formations and can be treated as ordinary monitoring areas. Depth points above 30% but below 70% can be considered to have a certain risk of complex formations, requiring close monitoring and appropriate preventative measures, and are marked as risk points in the initial assessment. Depth points above 70% can be considered to have a high probability of complex formations and must be subject to strong protective measures, and are marked as mandatory sealing points in the initial assessment.

[0040] The choice between these two approaches depends on the specific project requirements and the complexity of the geological conditions. For projects with relatively simple geological conditions, limited budgets, and a need for rapid decision-making, a single threshold (e.g., 50%) may be appropriate. However, for projects with complex geological conditions, requiring meticulous management, and seeking to improve drilling safety and economy through more precise risk assessment, a dual threshold method (e.g., 30% and 70%) is recommended. While this increases operational complexity, it significantly enhances the effectiveness and accuracy of risk management.

[0041] 104. Using the pre-set optimization process for different complex strata, the initial assessment must-sealing points and initial assessment risk points are reduced to obtain the final selection must-sealing points and final selection risk points corresponding to the target well.

[0042] In this step, since some of the initial assessment's mandatory sealing points and risk points may be mitigated through corresponding process optimization, it is crucial to accurately identify the risk points that truly require focused attention. This means determining, after optimization, which points still need to be considered as final mandatory sealing points and which can be considered as final risk points. These final selections will be used for subsequent casing design and other engineering measures.

[0043] One target risk point can be selected sequentially from the initial assessment of mandatory sealing points and initial assessment of risk points, and its corresponding target complex formation type (such as lost circulation zone, collapse zone, etc.) can be determined. For different complex formation types, a pre-set optimized process is adopted for treatment. For example, for lost circulation zones, special plugging materials or technologies can be used; for collapse zones, casing strength can be increased or chemical cementing agents can be used to enhance wellbore stability. Based on the target complex formation type, the optimized process and key parameters of adjacent wells for the same complex formation type are obtained. For example, if the target complex formation is a loss-prone zone, the plugging materials and technical parameters of adjacent wells under similar geological conditions can be referenced. Based on the successful experience of adjacent wells, the key parameters of the target well in the same depth range are modified. These key parameters may include, but are not limited to: formation pressure, temperature, mud density, type and amount of plugging material, casing strength and material selection, etc. During the actual drilling process of the target well, the above-mentioned adjusted key parameters and optimized processes are applied. For example, specific plugging agents are used in loss-prone zones, and casing strength is increased or hydrogen sulfide corrosion-resistant materials are used in high-pressure brine layers. Identify the upper and lower adjacent layers of the target complex stratum and obtain key parameters for each layer (such as formation pressure, temperature, and mud density). Compare the differences between the corrected key parameters of the target complex stratum and the key parameters of the upper and lower adjacent layers to determine if these differences are within a preset range. This preset range can be set according to engineering requirements and technical standards to ensure a smooth and safe transition between layers. If the differences between the corrected key parameters and the key parameters of adjacent layers are all within the preset range, the risk point is considered to have been effectively addressed and can be reduced. If the differences exceed the preset range, the risk point is retained and further processing is carried out according to its type label (risk point or mandatory sealing point).

[0044] 105. Based on the final selection of the mandatory sealing point and the final selection of the risk point, design the casing for the target well and determine the wellbore structure of the target well.

[0045] In this step, the required number of casing runs is determined based on the number and location of the final selected mandatory sealing points and risk points. For example, if a certain depth range is identified as a mandatory sealing point, a casing layer needs to be installed at that location. For each casing run corresponding to a depth segment, factors such as formation pressure, temperature, and corrosive media are considered to select appropriate casing materials, wall thickness, steel grade, and connection methods, resulting in corresponding casing structure parameters. For example, in high-temperature and high-pressure environments, high-strength casing materials resistant to hydrogen sulfide corrosion can be selected. The designed casing structure parameters are then evaluated, including safety indicators (such as internal pressure resistance, external extrusion resistance, and wellbore stability) and feasibility indicators (such as drilling time, casing installation difficulty, cementing quality, and economic efficiency). If the evaluation results do not meet all the preset standards for the above evaluation indicators, the casing structure parameters are iteratively adjusted until the optimal solution is reached. Once all the above evaluation indicators meet the preset standards, the final casing structure parameters are used as the wellbore structure design scheme for the target well.

[0046] Based on the above Figure 1 As can be seen from the implementation method, the technical solution provided in this application, by combining well logging interpretation data and seismic data from adjacent wells and the target well, establishes a three-dimensional comparison map containing the seismic characteristics, well logging characteristics, and actual drilling characteristics of the target well and adjacent wells at different depth domains. By comprehensively analyzing the seismic characteristics, well logging characteristics, and actual drilling characteristics of the target well and adjacent wells using the three-dimensional comparison map, the existence and probability distribution of complex strata can be more accurately identified, improving the accuracy of geological risk identification for complex strata. By quantitatively analyzing the probability distribution of different depth domains, the initial risk points and mandatory sealing points are identified, enabling a more scientific assessment of the possibility of the existence of complex strata. By using optimized processes to reduce the initial risk points and mandatory sealing points, the final selected risk points and mandatory sealing points are obtained, which can accurately determine the geological risk areas that need to be focused on. Based on the final selected mandatory sealing points and risk points, the casing design can ensure the safety and economy of the well structure, improve drilling efficiency, and reduce drilling costs. Compared with existing technologies, this application solves the problems of inaccurate geological risk identification and lack of systematic assessment in existing technologies through systematic and quantitative methods, and significantly improves the safety and economy of wellbore structure design when drilling deeper strata with more complex geological conditions.

[0047] In this embodiment of the application, before constructing a three-dimensional comparison map of the target well and the adjacent well in different depth domains based on the complex formation-actual drilling depth relationship map of the adjacent well, the seismic profile of the target well-adjacent well, and the logging interpretation profile of the target well-adjacent well, the method may further include: constructing a complex formation-actual drilling depth relationship map of the adjacent well based on the complex formation corresponding to the adjacent well in the target area and the actual drilling depth of the complex formation; constructing a seismic profile of the target well-adjacent well based on the original seismic data corresponding to the target well and the adjacent well, and constructing a seismic profile of the target well-adjacent well and a logging interpretation profile of the target well-adjacent well based on the original logging data corresponding to the target well and the adjacent well, respectively. The original logging data includes at least three of the following: sonic transit time, formation density, wellbore curve, and resistivity parameters.

[0048] The processor pre-extracts information about complex formations from the historical drilling records of adjacent wells. Complex formations include, but are not limited to, lost circulation zones, collapsed zones, brine layers, and oil and gas layers. The actual drilling depths of these complex formations in adjacent wells are obtained. The complex formations and their corresponding actual drilling depths are systematically organized, and a complex formation-actual drilling depth relationship map of adjacent wells is drawn using professional geological software (such as Petrel, Techlog, etc.) or custom-developed tools. This complex formation-actual drilling depth relationship map clearly shows the distribution of different complex formations in different depth domains of adjacent wells. The specific location, type, and potential risk points of each complex formation are marked on this complex formation-actual drilling depth relationship map. For example, the specific depth range and leakage characteristics of easily lost circulation zones are marked, where the original logging data includes at least three of the following: sonic transit time, formation density, wellbore curve, and resistivity parameters.

[0049] Cross-validating data from multiple adjacent wells ensures the accuracy of the complex formation-drilling depth relationship map. If inconsistencies or anomalies are found, further investigation and corrections are necessary. Additionally, geological experts can be invited to review the complex formation-drilling depth relationship map to ensure its scientific validity and rationality.

[0050] Acquire raw seismic and well logging data from the target well and adjacent wells, including parameters such as sonic transit time, resistivity, and formation density. Clean and standardize the seismic and well logging data. Use OpendTect software to process the seismic data, generating seismic profiles, specifically extracting key seismic features such as changes in reflection coefficients and amplitude attributes. Use Techlog software to interpret the well logging data, generating well logging interpretation profiles, which can be combined with sonic transit time, resistivity, and formation density for comprehensive analysis. Compare the seismic profile and well logging interpretation profile of the target well with those of adjacent wells to identify similarities and differences. For example, by comparing the seismic and well logging characteristics of adjacent wells, predict whether the target well has similar complex formations at the same depth. In practical applications, if conditions permit, small-scale test drilling can be used to obtain direct feedback to further verify and adjust the accuracy of the seismic profile and well logging interpretation profile.

[0051] In this embodiment of the application, determining the probability distribution of complex formations in different depth domains of the target well based on the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and adjacent wells in different depth domains may include: calculating the feature similarity between the target well and adjacent wells in different depth domains based on the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and adjacent wells in different depth domains; and determining the probability distribution of complex formations in different depth domains of the target well based on the feature similarity between the target well and adjacent wells in different depth domains.

[0052] It should be noted that the specific execution process for determining the probability distribution of complex formations in different depth domains of the target well, based on the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and adjacent wells, is as follows: Based on the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and adjacent wells in different depth domains, calculate the feature similarity between the target well and adjacent wells in different depth domains; based on the feature similarity between the target well and adjacent wells in different depth domains, determine the probability distribution of complex formations in different depth domains of the target well.

[0053] For seismic feature similarity, relevant functional modules in seismic interpretation software can be used to compare the seismic feature similarity between the target well and adjacent wells within the same depth domain. Specifically, methods such as cross-correlation coefficients and Euclidean distance can be used to quantify the degree of similarity. For well logging feature similarity, for each pair of adjacent and target wells within the same depth interval, the differences in their main logging curves (such as DT, RHOB, RES) can be compared, and the corresponding similarity score can be calculated. Combining the results of seismic and well logging feature similarity, a comprehensive similarity score is assigned to each depth domain, which can be achieved using a weighted average or by adjusting the weights according to specific circumstances.

[0054] Based on historical data from neighboring wells, a probabilistic model for the occurrence of complex formations is established. This model reflects the likelihood of complex formations occurring under different similarity scores. Statistical methods (such as logistic regression and Bayesian classifiers) can be used to construct the model, while machine learning algorithms (such as Support Vector Machines (SVM) and Random Forests (RF)) can be employed to improve prediction accuracy. The comprehensive similarity scores between the target well and neighboring wells at various depth domains are input into the established probabilistic model to derive the probability distribution of the presence of complex formations in the target well at the corresponding depth domains. This probability distribution can help the drilling team identify potential risk areas in advance and develop more scientific and reasonable drilling plans and contingency plans.

[0055] During actual drilling, the performance of the target well is continuously monitored and compared with the predicted results to evaluate the accuracy and effectiveness of the model. If significant deviations are found, model parameters should be adjusted or the model retrained in a timely manner to improve prediction accuracy. Furthermore, the database can be updated regularly to incorporate new drilling data, enabling the model to continuously learn and adapt to changes in geological conditions.

[0056] Through the detailed implementation methods described above, the probability distribution of complex formations in different depth regions of the target well can be effectively assessed based on seismic characteristics, logging characteristics, and actual drilling characteristics, providing important reference for drilling projects.

[0057] In this embodiment of the application, determining the initial risk points and initial mandatory sealing points corresponding to the target well based on the probability distribution of complex formations in different depth domains of the target well may include: taking the depth points in the probability distribution of complex formations in different depth domains of the target well that exceed the first probability but do not exceed the second probability as initial risk points, where the first probability is less than the second probability; and taking the depth points in the probability distribution of complex formations in different depth domains of the target well that exceed the second probability as initial mandatory sealing points.

[0058] It should be noted that the specific execution process for determining the initial risk points and initial mandatory sealing points of the target well based on the probability distribution of complex formations in different depth domains of the target well is as follows: the depth points in the probability distribution of complex formations in different depth domains of the target well that exceed the first probability but do not exceed the second probability are taken as initial risk points, with the first probability being less than the second probability; the depth points in the probability distribution of complex formations in different depth domains of the target well that exceed the second probability are taken as initial mandatory sealing points.

[0059] Specifically, for the first probability, a low probability threshold (e.g., 30%) is set to identify initial risk points. This threshold represents a medium-risk area, meaning complex formations may exist, but the risk is relatively low. For the second probability, a high probability threshold (e.g., 70%) is set to identify mandatory sealing points in the initial assessment. This threshold represents a high-risk area, meaning complex formations are very likely to occur, requiring stronger protective measures. The probability distribution results of the target well having complex formations in different depth domains are sorted by depth from smallest to largest and formed into a table or database record. Each record contains information such as depth and probability value. The probability values ​​of all depth points are iterated to find those depth points that exceed the first probability but do not exceed the second probability. For example, if the first probability is 30% and the second probability is 70%, depth points with probabilities between 30% and 70% are selected as initial risk points. Each initial risk point is labeled, and its specific depth range and probability value are recorded. Depth points with probability values ​​exceeding the second probability are identified. For example, if the second probability is 70%, depth points with probabilities greater than 70% are selected as mandatory sealing points in the initial assessment. Similarly, each point that must be sealed in the initial assessment is marked, and its specific depth range and probability value are recorded.

[0060] Through the detailed implementation methods described above, the initial risk points and the initial sealing points can be determined systematically based on the probability distribution of complex formations in different depth domains of the target well, providing an important reference for drilling projects.

[0061] In this embodiment, the optimization process preset for different complex formations is used to reduce the initial risk points and initial mandatory sealing points to obtain the final mandatory sealing points and final risk points corresponding to the target well. This can include: selecting a target risk point from the initial mandatory sealing points and initial risk points, and determining the target complex formation corresponding to the target risk point; obtaining the optimization results of the preset optimization process for the target complex formation in adjacent wells for the key parameters of the target layer, and correcting the key parameters of the target layer in the target well according to the optimization results to obtain the corrected key parameters of the target layer corresponding to the target complex formation, where the key parameters are the performance parameters targeted by the optimization process; determining the upper and lower adjacent layers corresponding to the target complex formation, and obtaining the upper and lower adjacent layer key parameters of the upper and lower adjacent layers respectively; determining whether the differences between the corrected key parameters of the target layer and the key parameters of the upper and lower adjacent layers are all within a preset range; if yes, the target risk point is reduced; if no, the target risk point is retained, and the target risk point is determined as a final mandatory sealing point or a final risk point according to the type label of the target risk point.

[0062] It should be noted that the specific execution process for reducing the initial risk points and initial mandatory sealing points using pre-set optimization processes for different complex formations to obtain the final mandatory sealing points and final risk points corresponding to the target well is as follows: A target risk point is selected sequentially from the initial mandatory sealing points and initial risk points, and the target complex formation corresponding to the target risk point is determined; the optimization results of the pre-set optimization process for the target complex formation are obtained in adjacent wells for the key parameters of the target layer; and the key parameters of the target layer are corrected in the target well based on the optimization results to obtain the corrected parameters corresponding to the target complex formation. The target layer's key parameters are the performance parameters targeted by the optimized process. The upper and lower adjacent layers corresponding to the target complex strata are determined, and their respective upper and lower adjacent key parameters are obtained. It is then determined whether the differences between the corrected target layer's key parameters and those of the upper and lower adjacent layers are all within a preset range. If so, the target risk point is reduced; otherwise, the target risk point is retained, and it is determined whether it is a mandatory final sealing point or a final risk point based on its type label.

[0063] In this step, target risk points can be selected sequentially from the initial assessment mandatory sealing points and initial assessment risk points. Based on geological data, determine the target complex formation type (such as well leakage layer, collapse layer, etc.) corresponding to the target risk point. For example, an initial assessment risk point at a depth of 2500m can be used as the first target risk point, as a well leakage layer may exist at 2500m. Find the optimized process and optimization results of key parameters for adjacent wells under the same complex formation type. For example, if an adjacent well also has a well leakage layer at the same depth, the successfully used plugging materials and technical parameters can be referenced. Based on the successful experience of adjacent wells, adjust the key parameters of the target well at the same depth. These key parameters may include, but are not limited to: formation pressure, temperature, mud density, type and amount of plugging material, casing strength and material selection. For example, assuming that a specific chemical plugging agent was used in an adjacent well, the mud density was adjusted to 1.3 through the use of this specific chemical plugging agent. Then, the same plugging agent is used in the target well, and the mud density is adjusted to the same value. Determine the upper and lower adjacent layers corresponding to the complex formation. For example, for a lost circulation zone at 2500m, the upper adjacent layer might be the formation at 2400m, and the lower adjacent layer might be the formation at 2600m. Obtain key parameters for the upper and lower adjacent layers, such as formation pressure, temperature, and mud density. Compare the differences between the corrected key parameters of the target layer and those of the upper and lower adjacent layers. For example, check whether the corrected mud density is consistent with or close to the mud density of the upper and lower adjacent layers. Set a reasonable preset range to ensure a smooth and safe transition between layers. For example, the preset range for mud density could be ±0.1. If the differences between the corrected target layer's key parameters and those of the adjacent upper and lower layers are all within a preset range, the risk point is considered effectively addressed and can be mitigated. If the differences exceed the preset range, the risk point is retained and further processed according to its type label (risk point or mandatory sealing point). For example, suppose the corrected mud density is 1.3. The mud densities of the adjacent layers are 1.2 and 1.2, respectively. and 1.4 The differences were all within ±0.1. Within the preset range, this risk point can be reduced if the corrected mud density is 1.5. The mud densities of the adjacent layers are 1.2 and 1.2, respectively. and 1.4 If the difference exceeds the preset range, the risk point needs to be retained and classified as a final mandatory sealing point or a final risk point according to the actual situation.

[0064] Through the detailed implementation methods described above, the initial risk points and the points that must be sealed in the initial assessment can be systematically optimized, significantly reducing geological risks and improving the safety and economy of drilling operations.

[0065] In this embodiment, the casing design for the target well based on the final selection of mandatory sealing points and risk points, and the determination of the wellbore structure, may include: determining the number of casing openings for the target well based on the number of risk points corresponding to the final selection of mandatory sealing points and risk points; designing the casing for the depth segment corresponding to each casing opening to obtain casing structure parameters, including the casing material, wall thickness, steel grade, and connection method; conducting an evaluation of the casing structure parameters based on the target well to obtain evaluation results, including feasibility indicators and safety indicators; if the feasibility indicators and safety indicators do not both meet their respective preset standards, the casing structure parameters are iteratively adjusted so that the feasibility indicators and safety indicators corresponding to the new casing structure parameters both meet their respective preset standards; if the feasibility indicators and safety indicators both meet their respective preset standards, the casing structure parameters are used as the wellbore structure.

[0066] The specific execution process for designing the casing and determining the wellbore structure of the target well based on the final selection of mandatory sealing points and risk points is as follows: The number of casing openings for the target well is determined according to the number of risk points corresponding to the final selection of mandatory sealing points and risk points; casing design is performed for the depth section corresponding to each casing opening, obtaining casing structure parameters, including casing material, wall thickness, steel grade, and connection method; based on the target well, the casing structure parameters are evaluated to obtain evaluation results, including feasibility and safety indicators; if the feasibility and safety indicators do not both meet their respective preset standards, the casing structure parameters are iteratively adjusted to ensure that the feasibility and safety indicators corresponding to the new casing structure parameters both meet their respective preset standards; if both the feasibility and safety indicators meet their respective preset standards, the casing structure parameters are used as the wellbore structure.

[0067] This step involves a detailed analysis of the complex formation types (such as lost circulation zones, collapse zones, and brine layers) corresponding to the final selection of mandatory sealing points and risk points, as well as their specific locations within the formation. The impact of the geostress field on wellbore stability is assessed, especially in high-stress areas where particular attention may be needed in casing design selection. The number of risk points is counted, and based on the number and distribution of the final selection of mandatory sealing points and risk points, the required number of casing passes for the target well is determined. For example, if multiple risk points exist at different depths, multi-layer casing design is required to address these risks. A corresponding depth segment is allocated to each casing pass to ensure that each layer of casing covers its corresponding risk point. The determination of casing structural parameters includes material selection, wall thickness design, steel grade selection, and connection methods. Specifically, appropriate casing materials are selected based on the geological conditions of each depth segment. For example, in high-pressure brine or oil and gas formations, special materials resistant to hydrogen sulfide corrosion can be selected. The required casing wall thickness is calculated based on formation pressure and temperature conditions. Higher formation pressures typically require thicker casing walls to ensure safety. Select the appropriate steel grade based on the maximum internal pressure and external extrusion strength requirements of the casing. For example, in deep, high-pressure formations, a high-strength steel grade is selected to enhance compressive strength. Choose a suitable casing connection method, such as threaded or welded connection, to ensure the sealing and strength of the connection.

[0068] After determining the casing structure parameters, an assessment of these parameters can be conducted based on the target well. This assessment includes feasibility evaluation and safety evaluation.

[0069] Feasibility assessment indicators include drilling time, casing installation difficulty, cementing quality, and economics. Specifically, it evaluates drilling efficiency under different casing designs. For example, larger wellbore sizes may reduce drilling speed, thus requiring optimization of wellbore size and casing layers. Factors such as casing weight, wellbore conditions (e.g., borehole enlargement rate), and drilling rig capacity are considered to ensure smooth casing installation without plastic deformation or other problems. Cementing simulation software is used to predict cement displacement effects and bond strength, ensuring high displacement efficiency and a flawless cement sheath during cementing. Finally, considering material costs, construction costs, and potential risk costs, the most cost-effective option is selected.

[0070] Safety performance assessment includes internal pressure resistance, external extrusion resistance, wellbore stability, and emergency response capabilities. Specifically, based on formation pressure predictions and a safety factor, the required internal pressure resistance of the casing is calculated. For example, for high-pressure brine formations, high-strength steel casing is selected to meet the internal pressure resistance requirements. A triaxial stress analysis model is used to evaluate the casing's external extrusion resistance under different operating conditions, ensuring its stability even under complex geological conditions. Wellbore stability analysis is conducted using seismic and logging data, and corresponding technical measures (such as adjusting mud density and using chemical cementing agents) are implemented to enhance wellbore stability. The effectiveness and operability of emergency plans are considered to ensure rapid response and action in emergency situations.

[0071] Check whether the feasibility and safety indicators meet their respective preset standards. For example, the internal pressure resistance must be higher than the maximum expected formation pressure, while the drilling time should be within a reasonable range. If some indicators do not meet the requirements, adjust the structural parameters (such as optimizing the wellbore size, changing the casing layer, or selecting a higher strength material) and re-evaluate until all indicators meet the standards. If both feasibility and safety indicators do not meet their respective preset standards, iteratively adjust the casing structural parameters until the optimal solution is reached. When both feasibility and safety indicators meet their respective preset standards, the final casing structural parameters are used as the wellbore structural design scheme for the target well.

[0072] In the embodiments of this application, before using the preset optimization processes of different complex formations to reduce the initial assessment must-sealing points and initial assessment risk points to obtain the final selection must-sealing points and final selection risk points corresponding to the target well, the method may further include: optimizing the wellbore trajectory of the target well based on the initial assessment must-sealing points and initial assessment risk points to reduce the initial assessment must-sealing points and initial assessment risk points.

[0073] The processor collects the current wellbore trajectory design, including parameters such as inclination angle, azimuth angle, and vertical depth. It performs a detailed analysis of the complex formation types (such as lost circulation zones, collapsed zones, and brine layers) corresponding to the initial assessment's mandatory sealing points and risk points, and their specific locations within the formation. It assesses the impact of the geostress field on wellbore stability, especially for high-stress areas where the wellbore trajectory design may require special attention. Optimization goals are pre-set, such as reducing the number of risk points, lowering the risk level, and improving drilling efficiency. Specifically, this can be achieved by adjusting the wellbore trajectory to avoid high-risk areas as much as possible, thereby reducing the number of initial assessment's mandatory sealing points and risk points. If completely avoiding certain high-risk areas is not feasible, the wellbore trajectory is adjusted to lower the risk level of these areas (e.g., changing them from mandatory sealing points to initial risk points). Optimizing the wellbore trajectory ensures a smoother drilling process, reduces unnecessary downtime and repair work, and improves overall drilling efficiency.

[0074] Using specialized wellbore trajectory design software (such as WellPlan and Landmark Compass), multiple potential wellbore trajectory design schemes are generated, each taking into account different geological conditions and drilling requirements. Each design scheme is simulated to assess its impact on the initial assessment of mandatory sealing points and initial assessment of risk points. The optimal scheme can be determined by calculating the probability changes of each risk point under each scheme. Based on the selected optimal scheme, the wellbore trajectory is gradually adjusted during the actual drilling process. Directional drilling technology can be employed to monitor and adjust the wellbore trajectory in real time, ensuring it follows the predetermined plan. During drilling, measurement-while-drilling (MWD) and logging-while-drilling (LWD) tools are used to monitor changes in the wellbore trajectory in real time and make necessary adjustments promptly.

[0075] This application also provides a device for determining wellbore structure based on geological risk, specifically as follows: Figure 2 As shown, the device includes:

[0076] The first building unit 31 is used to construct a three-dimensional comparison map of the target well and the adjacent well in different depth domains based on the complex formation-drilling depth relationship map of the adjacent well, the seismic profile of the target well-adjacent well and the well logging interpretation profile of the target well-adjacent well. The three-dimensional comparison map includes the seismic characteristics, well logging characteristics and actual drilling characteristics of the target well and the adjacent well in different depth domains. The complex formation includes at least one of the following: well leakage layer, collapse layer, brine layer and oil and gas layer.

[0077] The first determining unit 32 is used to determine the probability distribution of complex formations in different depth domains of the target well based on the seismic characteristics, logging characteristics and actual drilling characteristics of the target well and adjacent wells in different depth domains.

[0078] The second determining unit 33 is used to determine the initial assessment risk points and initial assessment mandatory sealing points of the target well based on the probability distribution of complex formations in different depth domains of the target well.

[0079] Processing unit 34 is used to reduce the initial assessment must-sealing points and initial assessment risk points by using the preset optimization process for different complex formations, so as to obtain the final selection must-sealing points and final selection risk points corresponding to the target well;

[0080] The third determining unit 35 is used to design the casing of the target well based on the final selection of the mandatory sealing point and the final selection of the risk point, and to determine the wellbore structure of the target well.

[0081] Furthermore, embodiments of this application also provide a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the above-described method.

[0082] Furthermore, embodiments of this application also provide a computer program product, including a computer program that, when executed by a processor, implements the steps of the above-described method.

[0083] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0084] It is understood that the relevant features in the above methods and apparatus can be referenced interchangeably. Furthermore, the terms "first," "second," etc., in the above embodiments are used to distinguish between embodiments and do not represent the superiority or inferiority of any particular embodiment.

[0085] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0086] The algorithms and displays provided herein are not inherently related to any particular computer, virtual system, or other device. Various general-purpose systems can also be used in conjunction with the teachings herein. The required structure for constructing such systems is apparent from the above description. Furthermore, this application is not directed to any particular programming language. It should be understood that the content of this application described herein can be implemented using various programming languages, and the above description of specific languages ​​is for the purpose of disclosing the best mode of implementation of this application.

[0087] In addition, the memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0088] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0089] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0090] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0091] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0092] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0093] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0094] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0095] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0096] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0097] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for determining wellbore structure based on geological risk, characterized in that, The method includes: Based on the complex formation-drilling depth relationship map of adjacent wells, the seismic profile of the target well-adjacent wells, and the logging interpretation profile of the target well-adjacent wells, a three-dimensional comparison map of the target well and the adjacent wells in different depth domains is constructed. The three-dimensional comparison map includes the seismic characteristics, logging characteristics, and drilling characteristics of the target well and the adjacent wells in different depth domains. The complex formation includes at least one of the following: lost circulation zone, collapsed zone, brine layer, and oil and gas layer. Based on the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and the adjacent well in different depth domains, the probability distribution of the existence of the complex formation in the target well in different depth domains is determined; Based on the probability distribution of the existence of the complex formation in different depth domains of the target well, determine the initial risk points and initial sealing points corresponding to the target well; By using different preset optimization processes for the complex formations, the initial assessment must-sealing points and the initial assessment risk points are reduced to obtain the final selection must-sealing points and final selection risk points corresponding to the target well; Based on the final selection of the mandatory sealing point and the final selection of the risk point, the casing design of the target well is carried out to determine the wellbore structure of the target well; The step of determining the initial risk point and the initial mandatory sealing point of the target well based on the probability distribution of the existence of the complex formation in different depth domains includes: taking the depth points in the probability distribution of the existence of the complex formation in different depth domains of the target well that exceed a first probability but do not exceed a second probability as the initial risk point, where the first probability is less than the second probability; and taking the depth points in the probability distribution of the existence of the complex formation in different depth domains of the target well that exceed the second probability as the initial mandatory sealing point.

2. The method according to claim 1, characterized in that, Before constructing a three-dimensional comparison map of the target well and adjacent wells in different depth domains based on the complex formation-drilling depth relationship map of adjacent wells, the seismic profile of the target well-adjacent wells, and the well logging interpretation profile of the target well-adjacent wells, the method further includes: Based on the complex formations corresponding to adjacent wells within the target area and the actual drilling depth of the complex formations, construct a complex formation-actual drilling depth relationship diagram for the adjacent wells; The target well-adjacent well seismic profile is constructed based on the original seismic data corresponding to the target well and the adjacent well, and the target well-adjacent well logging interpretation profile is constructed based on the original logging data corresponding to the target well and the adjacent well. The original logging data includes at least three of the following: sonic transit time, formation density, wellbore curve, and resistivity parameters.

3. The method according to claim 1, characterized in that, The step of determining the probability distribution of the existence of the complex formation in different depth domains of the target well based on the seismic characteristics, logging characteristics, and actual drilling characteristics of the target well and the adjacent wells in different depth domains includes: Based on the seismic features, logging features, and actual drilling features of the target well and the adjacent well in different depth domains, the feature similarity between the target well and the adjacent well in different depth domains is calculated. Based on the feature similarity between the target well and the adjacent well in different depth domains, the probability distribution of the presence of the complex formation in the target well in different depth domains is determined.

4. The method according to claim 1, characterized in that, The optimization process, based on different preset techniques for the complex formations, is used to reduce the initial risk points and the initial mandatory sealing points, respectively, to obtain the final mandatory sealing points and final risk points corresponding to the target well. This includes: Select one target risk point from the initial assessment mandatory sealing points and the initial assessment risk points, and determine the target complex strata corresponding to the target risk point; The optimization results of the preset optimization process for the target complex formation in the adjacent wells for key parameters of the target layer are obtained, and the key parameters of the target layer are corrected in the target well according to the optimization results to obtain the corrected key parameters of the target complex formation. The key parameters are the performance parameters targeted by the optimization process. Determine the upper and lower adjacent layers corresponding to the target complex strata, and obtain the key parameters of the upper and lower adjacent layers respectively. Determine whether the differences between the corrected target layer key parameters and the key parameters of the upper adjacent layer and the key parameters of the lower adjacent layer are all within a preset range; If so, then reduce the target risk points; If not, the target risk point is retained, and the target risk point is determined as the final mandatory sealing point or the final risk point according to the type label of the target risk point.

5. The method according to claim 1, characterized in that, The process of designing the casing for the target well based on the final selection of the mandatory sealing point and the final selection of the risk point, and determining the wellbore structure of the target well, includes: The number of casing openings for the target well is determined based on the number of risk points corresponding to the final selection mandatory sealing point and the final selection risk point; For each of the aforementioned casing openings, a casing design is performed for the corresponding depth segment to obtain casing structure parameters, which include the casing material, wall thickness, steel grade, and connection method. Based on the target well, the casing structure parameters are evaluated to obtain evaluation results, which include feasibility indicators and safety indicators. If the feasibility index and the safety index do not both meet their respective preset standards, the casing structure parameters are iteratively adjusted so that the feasibility index and safety index corresponding to the new casing structure parameters both meet their respective preset standards. If both the feasibility index and the safety index meet their respective preset standards, then the casing structure parameters will be used as the wellbore structure.

6. The method according to claim 1, characterized in that, Before using different preset optimization processes for the complex formations to reduce the initial assessment mandatory sealing points and initial assessment risk points to obtain the final selection mandatory sealing points and final selection risk points corresponding to the target well, the method further includes: Based on the initial assessment of mandatory sealing points and initial assessment of risk points, the wellbore trajectory of the target well is optimized to reduce the number of mandatory sealing points and initial assessment of risk points.

7. A device for determining wellbore structure based on geological risk, characterized in that, The device includes: The first construction unit is used to construct a three-dimensional comparison map of the target well and the adjacent well in different depth domains based on the complex formation-drilling depth relationship map of the adjacent well, the seismic profile of the target well-adjacent well, and the well logging interpretation profile of the target well-adjacent well. The three-dimensional comparison map includes the seismic characteristics, well logging characteristics, and drilling characteristics of the target well and the adjacent well in different depth domains. The complex formation includes at least one of the following: well leakage layer, collapse layer, brine layer, and oil and gas layer. The first determining unit is used to determine the probability distribution of the existence of the complex formation in the target well in different depth domains based on the seismic characteristics, logging characteristics and actual drilling characteristics of the target well and the adjacent well in different depth domains. The second determining unit is used to determine the initial risk point and the initial sealing point corresponding to the target well based on the probability distribution of the existence of the complex formation in different depth domains of the target well. The processing unit is used to reduce the initial assessment must-sealing point and the initial assessment risk point by using different preset optimization processes for the complex formations, so as to obtain the final selection must-sealing point and final selection risk point corresponding to the target well. The third determining unit is used to design the casing of the target well based on the final selection of the mandatory sealing point and the final selection of the risk point, and to determine the wellbore structure of the target well. The second determining unit is further configured to take the depth points in the probability distribution of the presence of the complex formation in different depth domains of the target well that exceed the first probability but do not exceed the second probability as the initial risk points, where the first probability is less than the second probability; and to take the depth points in the probability distribution of the presence of the complex formation in different depth domains of the target well that exceed the second probability as the initial mandatory sealing points.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method described in any one of claims 1-6.

9. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the steps of the method described in any one of claims 1-6.

Images