Method for identifying fractures in salt dome development area, identification system and storage medium

Abstract

The application provides a salt dome development area crack identification method, an identification system and a storage medium, and belongs to the field of geological exploration. The method comprises the following steps: establishing a regional dynamic crack model and locally updating the model; performing reverse dynamic analysis on each tectonic movement and the formed fault system in the target area to identify a single crack system generated by each tectonic movement in the corresponding geological horizon and establish a crack development model in the time dimension; and performing forward superposition analysis on the crack system in the target layer section in a multi-scale crack model fusion manner based on the crack development model to identify the crack system generated by each tectonic movement in the target layer section and the distribution position, development strength and development direction of the crack system. The application adopts four-dimensional crack prediction combining a dynamic crack model and forward and reverse time sequences, and combines multi-scale crack model fusion, so that the complex and variable crack development patterns of different parts of the salt dome can be accurately revealed, and data support can be provided for subsequent reservoir development and horizontal well design.

Description

Technical Field

[0001] This invention relates to the field of geological exploration technology, specifically to a method, system, and storage medium for identifying cracks in salt dome development areas. Background Technology

[0002] In salt dome development areas, the overlying dense carbonate rocks, under the influence of multiple (more than two) tectonic movements, form a unique and extremely complex fracture system. Its main characteristics are: controlled by different tectonic movements, multiple sets of fractures with different development directions and intensities overlap in different locations; due to the presence of the salt dome as a special geological body, these overlapping fractures exhibit developmental characteristics completely different from those in non-salt dome areas. These characteristics pose new requirements for fracture prediction, and conventional fracture prediction methods are no longer sufficient for salt dome development areas.

[0003] Currently developed techniques for predicting fractures in carbonate reservoirs include shear wave splitting, P-wave AVAZ (Amplitue Versus Azmuith) amplitude-azimuth anisotropy, and multi-attribute seismic attribute fusion. However, multi-component seismic acquisition and processing are expensive and therefore less commonly used. P-wave AVAZ is another effective seismic fracture prediction technique, but it requires wide-azimuth seismic data and specific processing techniques, limiting its application. Multi-attribute seismic attribute fusion is a widely used technique for predicting fractures in carbonate reservoirs. While this method can generally meet the requirements for fracture prediction, its main drawbacks are: limited by the resolution of seismic data, it cannot identify small-scale fractures; for mesoscale fractures, it is severely limited by data quality, often unable to distinguish between noise and signal without supporting data, resulting in significantly reduced prediction accuracy for small and medium-scale fractures.

[0004] In summary, in the salt dome region influenced by multiple tectonic movements, multiple sets of cracks dynamically change and overlap, which places higher demands on crack identification and prediction methods. Existing technologies are not yet sufficient to solve this problem. Summary of the Invention

[0005] This invention provides a method, system, and storage medium for identifying fractures in salt dome development areas. It employs a unique prediction method for multiple sets of fractures within salt dome development areas. The aim is to identify the dynamic changes of multiple sets of fractures in target reservoirs within salt dome development areas under the influence of multiple tectonic movements, characterize the direction and development intensity of fractures, and predict the spatial distribution of fractures, thereby providing data support for subsequent development of reservoirs and horizontal well placement.

[0006] The purpose of this invention is to provide a method for identifying fractures in salt dome development areas. The method includes: establishing a regional dynamic fracture model based on tectonic movements in the target area and the fracture systems formed by these movements; updating the regional dynamic fracture model locally based on the interpretation of three-dimensional seismic data from local geological strata; performing reverse dynamic analysis on the updated regional dynamic fracture model to identify single fracture systems generated by each tectonic movement at their corresponding geological strata and establishing a fracture development model of the single fracture system in the time dimension; and performing forward superposition analysis on the fracture systems within the target stratum using a multi-scale fracture model fusion approach based on the fracture development model to identify the fracture systems generated by each tectonic movement in the target stratum and the distribution location, development intensity, and development direction of the fracture systems within the salt dome development area.

[0007] Optionally, the multi-scale fracture model includes: a one-dimensional microfracture model based on rock core and imaging logging data, used to identify fractures smaller than or equal to a first scale threshold; and a mesoscale fracture model based on four-dimensional analysis of multiple seismic attributes, used to identify fractures larger than the first scale threshold.

[0008] Optionally, the one-dimensional microfracture model is established through the following steps: Based on fracture development parameters of rock cores in designated characteristic wells, an initial one-dimensional fracture model is established under the constraints of the regional dynamic fracture model, wherein the fracture development parameters include longitudinal development intensity and fracture angle; the initial one-dimensional fracture model is updated by cross-comparing the fracture development parameters of rock cores in multiple characteristic wells to obtain a first updated model; the first updated model is updated a second time based on imaging logging data from the multiple characteristic wells to obtain a second updated model; and the direction of the maximum principal stress in the second updated model is input into the regional dynamic fracture model for verification, and the verified second updated model is determined as the one-dimensional microfracture model.

[0009] Optionally, establishing a regional dynamic fracture model based on the tectonic movements of the target area and the fracture systems formed by each tectonic movement includes: determining the tectonic movement unit where the target area is located through tectonic plate analysis; performing plate seismic sequence analysis on the tectonic movement unit to determine each tectonic movement within the target area; identifying the fracture systems formed by each tectonic movement and their characteristic parameters through tectonic geomechanical analysis, wherein the characteristic parameters include fracture development direction, fracture intensity, and distribution range; and establishing the regional dynamic fracture model based on the tectonic movements and the characteristic parameters of the fracture systems.

[0010] Optionally, the structural motion includes one or more of the following: fracture tension motion, slip-slip tension motion, and compression motion.

[0011] Optionally, the localization update of the regional dynamic fracture model based on the interpretation of the 3D seismic data volume of the local geological strata includes: determining the effect of the tectonic movement on the local geological strata based on the interpretation of the 3D seismic data volume to obtain a geological structure map of the local geological strata; selecting geological strata after the occurrence of the tectonic movement from the local geological strata and performing a flattening operation to restore the paleomorphological features of the geological strata; selecting a seismic profile penetrating the salt dome from the 3D seismic data volume to obtain the tectonic high points and dynamic changes in stratigraphic thickness of the salt dome; and updating the regional dynamic fracture model locally based on the geological structure map of the local geological strata, the paleomorphological features of the geological strata, and the seismic profile of the salt dome.

[0012] Optionally, the three-dimensional seismic data volume includes one or more of the following: chaotic volume, curvature volume, variance volume, and ant volume.

[0013] Optionally, after performing forward superposition analysis on the fracture system within the target segment based on the fracture development model using a multi-scale fracture model fusion method, the fracture identification method further includes: verifying the identified fracture development based on the production well reservoir production data within the target area.

[0014] On the other hand, the present invention also provides a fracture identification system for salt dome development areas. The fracture identification system includes: a model building device for establishing a regional dynamic fracture model based on tectonic movements in the target area and the fracture systems formed by each tectonic movement; a localization update device for updating the regional dynamic fracture model locally based on the interpretation of three-dimensional seismic data volumes of local geological strata; a reverse dynamic analysis device for performing reverse dynamic analysis on each tectonic movement and the fracture systems formed in the target area based on the locally updated regional dynamic fracture model, so as to identify the single fracture system generated by each tectonic movement in its corresponding geological strata and establish a fracture development model of the single fracture system in the time dimension; and a forward superposition analysis device for performing forward superposition analysis on the fracture system in the target segment based on the fracture development model in a multi-scale fracture model fusion manner, so as to identify the fracture system generated by each tectonic movement in the target segment and the distribution location, development intensity and development direction of the fracture system in the salt dome development area.

[0015] In another aspect, this application provides a machine-readable storage medium storing instructions for causing a machine to execute: the crack identification method for salt dome development regions described above.

[0016] Through the above technical solution, this invention proposes for the first time a four-dimensional fracture prediction method based on a dynamic fracture model in salt dome development areas. It adopts a combination of forward and reverse time series-based four-dimensional fracture prediction guided by a dynamic fracture conceptual model and multi-disciplinary data comprehensive analysis. By combining multi-scale fracture model fusion, it verifies fractures of different scales in different parts of the salt dome development area. This method can more accurately reveal the complex and variable fracture development patterns in different parts of the salt dome and provide data support for subsequent reservoir development and horizontal well design.

[0017] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0019] Figure 1 This is a flowchart illustrating a method for identifying cracks in a salt dome development area according to an embodiment of this application;

[0020] Figure 2 This is a schematic diagram illustrating the dynamic crack prediction workflow according to an embodiment of this application;

[0021] Figure 3 This is a schematic diagram illustrating the crack prediction process for the target layer according to an embodiment of this application;

[0022] Figure 4 A schematic diagram illustrating the establishment of a regional dynamic crack conceptual model according to an embodiment of this application;

[0023] Figures 5a-5c This is a schematic diagram illustrating the localization process of the crack conceptual model according to an embodiment of this application;

[0024] Figure 6 This is a schematic diagram of a crack conceptual model according to an embodiment of this application;

[0025] Figure 7 This is a schematic diagram illustrating the decomposition of a four-dimensional crack identification-reverse time multi-stage crack system according to an embodiment of this application;

[0026] Figure 8 This is a schematic diagram illustrating multi-stage crack identification in a salt dome area according to an embodiment of this application;

[0027] Figure 9 This is a schematic diagram of core data analysis according to an embodiment of this application;

[0028] Figure 10 This is a schematic diagram illustrating the relationship between imaging logging analysis - fracture azimuth and dip angle and salt dome, according to an embodiment of this application.

[0029] Figure 11 This is a schematic diagram of a crack identification system for a salt dome development area according to an embodiment of this application. Detailed Implementation

[0030] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0031] Paleozoic salt domes and salt diapirs are widely developed in the southwestern Persian Gulf. The applicant discovered that in salt dome areas, four-directional closed structures frequently appear in the overlying strata, forming a tectonic trap. Under the influence of multiple phases of tectonic movement, the overlying dense carbonate rocks have formed a complex and variable fracture system. Due to the presence of salt dome structures, the multi-phase tectonic movements have created a fracture structure style in salt dome areas that is completely different from that in non-salt dome areas. This uniqueness is manifested in the different locations of the salt dome structures, where the structural style, fracture system development scale, direction, intensity, and closure all exhibit differences, posing higher demands on conventional fracture prediction and identification methods.

[0032] It is evident that identifying multi-stage fractures in the overlying dense carbonate rocks presents a challenge in salt dome development areas. To address this, this invention first provides a fracture identification method 100 for salt dome development areas, which can perform four-dimensional fracture identification based on a dynamic fracture model. For example... Figure 1 As shown, the crack identification method 100 may include steps S110-S140. A detailed flowchart of the dynamic crack prediction workflow can be found in [reference needed]. Figure 2 and Figure 3 As shown.

[0033] Step S110: Based on the tectonic movements of the target area and the fracture system formed by each tectonic movement, establish a regional dynamic crack model.

[0034] In one embodiment, step S110 may include steps S111-S114:

[0035] Step S111: Through structural plate analysis, determine the structural motion unit where the target area is located.

[0036] First, by analyzing the tectonic plates, the tectonic movement unit where the target area is located can be determined, such as the Arabian Plate in this embodiment.

[0037] Step S112: Perform plate seismic sequence analysis on the tectonic movement units to determine the various tectonic movements within the target area.

[0038] Specifically, such as Figure 4 As shown, data analysis based on ophiolites and plate seismic sequence analysis can be carried out to determine the main tectonic movements in the region. These tectonic movements can include one or more of the following: fault-stretching, strike-slip stretching, and compressional movements. In this embodiment, the tectonic movements in the target region can be identified as: Jurassic fault-stretching, Cretaceous strike-slip stretching, and Tertiary compressional movements.

[0039] Step S113: Identify the fracture systems and their characteristic parameters formed by each tectonic movement through structural geomechanical analysis.

[0040] Specifically, tectonic geomechanical analysis can be performed to identify the corresponding fault systems and their key characteristic parameters formed by each tectonic movement. These key characteristic parameters can include the fault development direction, fault strength, and main distribution range and characteristics.

[0041] Step S114: Establish a regional dynamic crack model based on the tectonic motion and the characteristic parameters of the fracture system.

[0042] Specifically, a regional dynamic fracture model can be established based on tectonic motion and the characteristic parameters of the fracture system. For example... Figure 4 As shown, firstly, the dynamic relationship between major tectonic movements (such as the Jurassic fault-stretching movement, the Cretaceous strike-slip stretching movement, and the Tertiary compressional movement) and the landmark stratigraphic systems (Jurassic Arabite, Cretaceous Mishrif, and Tertiary Rus) is established vertically; secondly, based on the dynamic relationship, the dynamic evolution of fractures within a single landmark stratum and the temporal evolution of fractures based on multiple sets of landmark strata are identified, thus ultimately forming a regional dynamic fracture conceptual model.

[0043] One of the key features of this invention is the use of a dynamic fracture concept model, which can dynamically analyze regional tectonic movements and the corresponding fracture systems. It can determine the possibility of multi-stage fracture development and the development characteristics of each stage of the fracture system from the perspective of genesis, guide fracture prediction in core, imaging logging, and especially seismic data, reduce the ambiguity of fracture prediction, and eliminate erroneous predictions of small and medium-scale fractures caused by poor seismic data quality.

[0044] Step S120: Based on the interpretation of the three-dimensional seismic data volume of the local geological strata, the regional dynamic fracture model is updated locally.

[0045] Among them, see Figures 5a-5cLocal geological data mainly refers to geological structural maps, seismic profiles, and paleogeomorphic maps generated from seismic data. This step is to localize and update the regional dynamic fracture model based on the geological structural maps, seismic profiles, and paleogeomorphic maps generated from seismic data.

[0046] In one embodiment, step S120 may include steps S121-S124:

[0047] Step S121: Based on the interpretation of the three-dimensional seismic data volume, determine the effect of tectonic movement on local geological strata to obtain a geological structure map of the local geological strata.

[0048] Specifically, guided by the regional fracture conceptual model, parameters conforming to the fracture conceptual model are selected to generate various three-dimensional seismic attribute volumes, mainly including but not limited to chaotic volumes, curvature volumes, variance volumes, and ant volumes. That is, the three-dimensional seismic data volume can include one or more of the following: chaotic volumes, curvature volumes, variance volumes, and ant volumes, etc. Then, three-dimensional seismic data interpretation can be performed to generate structural top-level maps of key geological layers from shallow to deep, such as... Figure 5a As shown. Furthermore, the dynamic changes in structural morphology are analyzed, especially the evolution of structural morphology during major tectonic movements, so as to determine the effect of tectonic movements on local geological strata and adjust and optimize the regional fracture conceptual model.

[0049] Step S122: Select a geological stratum that occurred after tectonic movement in the local geological strata and perform a flattening operation to restore the paleomorphological features of the geological stratum.

[0050] Specifically, such as Figure 5b As shown, local paleotectonic reconstruction can be performed. For the geological periods in which major tectonic movements occurred, geological strata before the tectonic movements are selected, and those after the movements are flattened to reconstruct the paleomorphological features of those strata. Then, the local tectonic patterns, corresponding fault system characteristics, and differences from regional fracture conceptual models can be analyzed, and the model can be updated using the aforementioned data.

[0051] Paleotectonic restoration involves selecting specific geological strata and flattening them to obtain the results. This is one method of paleotectonic restoration. In practical applications, two factors need to be considered when selecting geological strata: the flattened strata should be as close as possible to the target strata; and to reduce the influence of subsequent tectonic movements, the strata should be selected from sedimentary strata that have experienced less tectonic activity and are from a relatively stable period.

[0052] Step S123: Select a seismic profile that runs through the salt dome from the three-dimensional seismic data volume to obtain the tectonic high points and dynamic changes in stratum thickness of the salt dome.

[0053] Specifically, such as Figure 5cAs shown, it is necessary to select a seismic profile that penetrates the salt dome from the three-dimensional seismic data volume, and then analyze the dynamic changes of tectonic high points and stratum thickness to further determine the intensity of tectonic movement and the relationship between the corresponding fracture distribution and the salt dome.

[0054] In practical applications, salt domes are usually known. The specific method of penetration can depend on the morphology of the salt dome, generally choosing two approaches: one perpendicular to the salt dome's strike, and the other parallel to the strike. A thick salt dome typically indicates strong tectonic activity, as intense tectonic activity can create large spaces (basins) for sediment deposition, forming thick strata. Similarly, the elevation of the highest points on a salt dome can also reflect the intensity of tectonic movement.

[0055] Step S124: Based on the geological structure map of the local geological strata, the paleogeomorphology of the geological strata, and the seismic profile of the salt dome, the regional dynamic fracture model is updated locally.

[0056] Specifically, by combining the data obtained in steps S121-123, including the geological structure map of the local geological strata, the paleogeomorphological features of the geological strata, and the seismic profiles of the salt domes, the regional dynamic fracture model can be localized and updated to obtain... Figure 6 The updated crack conceptual model is shown.

[0057] Through the above steps, this invention can innovatively analyze the structural development characteristics of the main parts of the salt dome under the action of the main tectonic stress field, targeting the main tectonic movements in the region. This allows for the decomposition of the unique dynamic change patterns of multi-stage cracks within the salt dome region, enabling relatively high-precision analysis within the target area and localization of the dynamic crack model. This lays the foundation for subsequent crack identification in the target layer.

[0058] Step S130: Based on the localized updated regional dynamic fracture model, perform reverse dynamic analysis on each tectonic movement and the resulting fracture system in the target area to identify the single fracture system generated by each tectonic movement in its corresponding geological stratum and establish a fracture development model of the single fracture system in the time dimension.

[0059] Specifically, seismic attribute data of geological strata corresponding to the major tectonic movements can be extracted. In this example, from oldest to youngest, these are the Jurassic Arabite strata, the Cretaceous Mishrif strata, and the Tertiary Rus strata. In this step, a reverse dynamic analysis (reverse time sequence) needs to be performed on the major tectonic movements (Jurassic fault-stretching, Cretaceous strike-slip stretching, and Tertiary compressional movements) and the resulting fracture systems. This involves a dynamic evolution analysis from shallow to deep and from youngest to oldest, establishing a fracture development model of a single fracture system related to tectonic movements in the time dimension (the fourth dimension), such as... Figure 7As shown. That is, the directional dynamic analysis in this step is a reverse time sequence, analyzing the characteristics of a series of local tectonic movements from newest to oldest, as well as the development of the corresponding fracture system (cracks), so as to identify the main (single) cracks and characteristics generated by each tectonic movement in its corresponding geological stratum (i.e., the geological stratum closest to this tectonic movement).

[0060] The purpose of this step is to achieve four-dimensional fracture identification in target areas based on multiple seismic attributes. That is, under the constraints of the aforementioned dynamic fracture model, this invention can add additional control variables to the four-dimensional fracture identification method based on multiple seismic attributes, enabling better identification of fracture distribution in the target area. Generally speaking, the size of fractures is not related to their development time, but only depends on the magnitude of the stress on the formation.

[0061] Then, for the main tectonic movements in the target area, repeat the above analysis process, perform forward superposition analysis (time sequence) on the fracture system in the target layer, and identify the dynamic changes and development characteristics of fractures in the salt dome area, as detailed in step S140.

[0062] Step S140: Based on the fracture development model, a forward superposition analysis of the fracture system in the target segment is performed by fusing multi-scale fracture models to identify the fracture system generated by each tectonic movement in the target segment, as well as the distribution location, development intensity, and development direction of the fracture system within the salt dome development area.

[0063] In other words, based on the reverse dynamic analysis in step S130 to clarify the characteristics of tectonic movement in the work area, this step S140 further analyzes the crack development of each tectonic movement in the target layer in a forward manner, such as... Figure 8 As shown. That is, under the guidance of the dynamic fracture model, the present invention can eliminate coherent noise in the seismic attribute volume of the target layer, identify the fracture system generated by each tectonic movement in the target layer, that is, various (multiple) fractures and their characteristics, and at the same time identify the distribution location, development intensity and development direction of the fracture system in the salt dome area.

[0064] In summary, this invention is based on four-dimensional fracture identification using multiple seismic attributes. It innovatively establishes a four-dimensional fracture analysis method combining forward and reverse temporal sequences. This method performs reverse temporal analysis (from newest to oldest) on multiple tectonic movements, using multiple seismic attributes to decompose the development patterns of multi-phase fracture systems in three-dimensional space. Forward temporal analysis (from oldest to newest) is then performed on the target stratigraphic level, superimposing the multi-phase fracture systems to identify the evolution and development patterns of fractures within the target stratigraphic segment.

[0065] Furthermore, due to limitations in seismic data resolution, seismic data can generally only identify large-scale and mesoscale fractures. Large-scale fractures or faults have obvious characteristics and are relatively easy to identify, while mesoscale fractures, because their scale is close to the seismic wavelength, fall into a blurry area for identification. Fractures are easily confused with noise, and their identification heavily depends on the seismic data itself. In salt dome areas, reservoirs, under the influence of multiple tectonic movements, exhibit more complex characteristics with multiple sets of fractures in the salt dome development zone, making fractures and coherent noise almost indistinguishable in seismic data.

[0066] To address this, this invention integrates a one-dimensional microfracture model based on rock core and imaging logging data, and a mesoscale fracture model based on four-dimensional analysis of multiple seismic attributes, on the basis of a conceptual fracture model based on regional and local tectonic evolution analysis. By fusing these multi-scale fracture models, different scale fractures at different scales in different parts of salt dome development areas are cross-validated to identify the spatial distribution, fracture angles, and development intensity of multiple sets of fractures within tight carbonate reservoirs. In one embodiment, the multi-scale fracture model may include:

[0067] 1) A one-dimensional microfracture model based on rock core and imaging logging data can be used to identify fractures smaller than or equal to a first scale threshold. That is, it can be used to identify small-scale fractures. Generally, the scale of small-scale fractures is less than the meter level, so the first scale threshold can be defined as 1-10m. Preferably, the scale of small-scale fractures is ≤1m or ≤10m.

[0068] 2) The mesoscale fracture model based on four-dimensional analysis of multiple seismic attributes can be used to identify fractures larger than the first scale threshold. That is, it can be used to identify medium- and large-scale fractures. Generally, large-scale fractures are on the order of kilometers and can be defined as >km; while mesoscale fractures are larger than meters and can be defined as >1m or >10m. Preferably, the scale of mesoscale fractures is 1-10m or 10-1000m.

[0069] Specifically, a one-dimensional microcrack model can be established through the following steps:

[0070] 1) Based on the fracture development parameters of rock cores in the designated characteristic wells, an initial one-dimensional fracture model is established under the constraints of a regional dynamic fracture model. The fracture development parameters may include longitudinal development intensity and fracture angle.

[0071] This step involves selecting a specific well and using its rock core data to create a preliminary model. For example... Figure 9As shown, a preliminary one-dimensional small-scale fracture model is constructed based on its rock core data. Specifically, for key geological strata corresponding to major tectonic movements, small-scale fractures can be identified in the rock core at the wellpoint locations of designated characteristic wells (exploration wells). Under the constraints of the fracture model established in the previous step, and combined with the calculated longitudinal development intensity (density) and fracture angle of the rock core fractures, an initial one-dimensional small-scale fracture model is established.

[0072] 2) The initial one-dimensional fracture model is updated by cross-comparing the fracture development parameters of rock cores from multiple characteristic wells to obtain the first updated model.

[0073] This step involves selecting multiple characteristic wells for cross-comparison to update the aforementioned model. Specifically, small-scale fractures identified in the core samples of multiple characteristic wells can be cross-compared. Based on their lateral location, the relationship between fracture development and different parts of the salt dome can be analyzed, thereby performing the first update to the initial one-dimensional fracture model to obtain the first updated model.

[0074] It should be noted that fractures in multiple characteristic wells are more spatial control points, while fracture prediction between well points relies more on seismic data.

[0075] 3) Based on the imaging logging data from multiple characteristic wells, the first update model is updated a second time to obtain the second update model.

[0076] This step involves updating the model again based on imaging logging data from multiple characteristic wells. For example... Figure 10 This illustrates the updating of a one-dimensional small-scale fracture model based on imaging logging data analysis. Imaging logging data requires multiple feature wells because fracture characteristics differ at different locations. Therefore, multiple points can be used as positioning points to control the study area on a planar surface.

[0077] Specifically, micro-fracture (small-scale) analysis based on imaging logging data can be conducted at well points to identify the fracture development orientation, angle, and current direction of the maximum principal stress underground. Small-scale fractures (direction and scale) can be directly identified by acquiring imaging logging data from exploration wells. It is important to note that although a well appears as a straight line in three-dimensional space, this does not necessarily mean the fractures are vertical. Subsequently, fracture identification analysis based on a fracture conceptual model can be performed. Due to the potential for multiple interpretations of fracture identification caused by variations in the quality of imaging logging data, this invention can identify fractures that conform to geomechanical and geological principles under the constraints of the fracture conceptual model. Finally, the micro-fracture information identified based on imaging logging analysis can be updated into a one-dimensional small-scale fracture model, thus controlling the distribution pattern of micro-fractures in the salt dome area at the well point location. In other words, through the analysis of the aforementioned rock cores and imaging logging data, this invention can establish a dynamic model of small-scale fractures at control points (well points) in the salt dome area, thereby characterizing the development patterns of small-scale fractures at different locations within the salt dome and effectively supplementing the dynamic fracture conceptual model.

[0078] 4) Input the direction of the maximum principal stress in the second updated model into the dynamic crack model of the region for verification, and determine the second updated model that passes the verification as a one-dimensional microcrack model.

[0079] This step is to verify whether the principal stress directions are consistent. If the verification is successful, it will be used as the small crack identification model. Specifically, the identified maximum principal stress direction can be cross-validated with the dynamic crack conceptual model. In this example, based on induced crack analysis, the current maximum principal stress direction in the second updated model is found to be NE-SW, while the most recent tertiary principal stress direction in the crack model is also NE-SW compressive motion. It can be seen that the principal stress directions of the two are consistent, thus indicating that the dynamic crack conceptual model has been successfully verified.

[0080] Through the above technical solution, this invention provides a method for predicting multi-stage fractures in salt dome development areas, especially in tight carbonate reservoirs. It employs a four-dimensional fracture prediction method combining forward and reverse time series analysis guided by a dynamic fracture conceptual model, along with multidisciplinary data comprehensive analysis. This method can identify and predict the spatial distribution and development intensity of multi-stage fractures in the reservoir overlying the salt dome. This invention is the first to propose a four-dimensional fracture prediction method based on a dynamic fracture model in salt dome development areas. This method can accurately reveal the complex and variable fracture development patterns in different parts of the salt dome, providing data support for subsequent reservoir development and horizontal well design.

[0081] In one embodiment, after step S140, the fracture identification method 100 of the present invention may further include: step S150, verifying the identified fracture development based on the production data of the production wells in the target area. Specifically, the production well reservoirs in the target area can be analyzed. Due to the low permeability of the reservoir matrix, the reservoir production is normally limited. However, actual test data analysis shows that the reservoir production is relatively large, which can indirectly corroborate the fracture development characteristics. That is, the test data proves the contribution of fracture development to the production of tight carbonate reservoirs.

[0082] The beneficial effects that the present invention can achieve through the above technical solution include:

[0083] 1) A dynamic fracture conceptual model is adopted. The regional tectonic movement and the corresponding fracture system are dynamically analyzed to determine the possibility of multi-stage fracture development and the development characteristics of each stage of fracture system from the perspective of genesis. This guides fracture prediction in core, imaging logging, and especially seismic data, reducing the ambiguity of fracture prediction and eliminating erroneous predictions of small and medium-scale fractures caused by poor seismic data quality.

[0084] 2) Localization analysis of dynamic fracture model. Based on the major tectonic movements in the region, the development characteristics of the structural patterns of the main parts of the salt dome under the action of the main tectonic stress field were innovatively analyzed. This decomposed the unique dynamic change patterns of multi-stage fractures within the salt dome region, realizing the localization of the dynamic fracture model and laying the foundation for subsequent fracture identification of the target layer.

[0085] 3) One-dimensional small-scale fracture model. Through analysis of rock core and imaging logging data, a dynamic model of small-scale fractures at control points (well points) in the salt dome area was established, which characterized the development law of small-scale fractures at different locations in the salt dome and effectively supplemented the dynamic fracture conceptual model.

[0086] 4) Four-dimensional fracture identification based on multiple seismic attributes. An innovative four-dimensional fracture analysis method combining forward and reverse time series is established. Reverse time series analysis (from newest to oldest) is carried out on multiple tectonic movements, and the development law of the multi-phase fracture system in three-dimensional space is decomposed using multiple seismic attributes. For the target layer, forward time series analysis (from oldest to newest) is carried out, and the multi-phase fracture system is superimposed to identify the fracture evolution and development law in the target layer.

[0087] On the other hand, the present invention also provides a crack identification system 200 for salt dome development areas, such as... Figure 11 As shown, the crack identification system 200 may include:

[0088] The model building device 210 is used to establish a regional dynamic crack model based on the tectonic movements of the target area and the fracture system formed by each tectonic movement.

[0089] The localization update device 220 is used for the interpretation of three-dimensional seismic data volumes based on local geological strata to perform localization updates on the regional dynamic fracture model.

[0090] The reverse dynamic analysis device 230 is used to perform reverse dynamic analysis on each tectonic movement and the resulting fracture system in the target area based on the localized updated regional dynamic fracture model, so as to identify the single fracture system generated by each tectonic movement in its corresponding geological stratum and establish a fracture development model of the single fracture system in the time dimension.

[0091] The forward superposition analysis device 240 is used to perform forward superposition analysis on the fracture system in the target layer based on the fracture development model and in a multi-scale fracture model fusion manner, so as to identify the fracture system generated by each tectonic movement in the target layer and the distribution location, development intensity and development direction of the fracture system in the salt dome development area.

[0092] In one embodiment, the multi-scale fracture model includes: a one-dimensional microfracture model based on rock core and imaging logging data, used to identify fractures smaller than or equal to a first scale threshold; and a mesoscale fracture model based on four-dimensional analysis of multiple seismic attributes, used to identify fractures larger than the first scale threshold.

[0093] In one embodiment, the one-dimensional microfracture model is established through the following steps: Based on fracture development parameters of rock cores in designated characteristic wells, an initial one-dimensional fracture model is established under the constraints of the regional dynamic fracture model, wherein the fracture development parameters include longitudinal development intensity and fracture angle; the initial one-dimensional fracture model is updated by cross-comparing the fracture development parameters of rock cores in multiple characteristic wells to obtain a first updated model; the first updated model is updated a second time based on imaging logging data from the multiple characteristic wells to obtain a second updated model; and the direction of the maximum principal stress in the second updated model is input into the regional dynamic fracture model for verification, and the verified second updated model is determined as the one-dimensional microfracture model.

[0094] In one embodiment, the model building device 210 can be specifically used to perform: determining the tectonic movement unit where the target area is located through tectonic plate analysis; performing plate seismic sequence analysis on the tectonic movement unit to determine each tectonic movement within the target area; identifying the fracture system formed by each tectonic movement and its characteristic parameters through tectonic geomechanical analysis, wherein the characteristic parameters include fracture development direction, fracture intensity and distribution range; and establishing a dynamic fracture model of the area based on the tectonic movement and the characteristic parameters of the fracture system.

[0095] In one embodiment, the structural motion includes one or more of the following: fracture stretching motion, slip stretching motion, and compression motion.

[0096] In one embodiment, the localization update device 220 may specifically be used to perform: based on the interpretation of the three-dimensional seismic data volume, determine the effect of the tectonic movement on the local geological strata to obtain a geological structure map of the local geological strata; select a geological stratum in the local geological strata after the occurrence of the tectonic movement and perform a flattening operation to restore the paleomorphological features of the geological strata; select a seismic profile penetrating the salt dome from the three-dimensional seismic data volume to obtain the tectonic high points and dynamic changes in stratum thickness of the salt dome; and perform localization update of the regional dynamic fracture model based on the geological structure map of the local geological strata, the paleomorphological features of the geological strata, and the seismic profile of the salt dome.

[0097] In one embodiment, the three-dimensional seismic data volume includes one or more of the following: chaotic volume, curvature volume, variance volume, and ant volume.

[0098] In one embodiment, the fracture identification system 200 further includes a verification device for verifying the development of identified fractures based on production well reservoir production data within the target area.

[0099] The beneficial effects that the present invention can achieve through the above technical solution include:

[0100] 1) A dynamic fracture conceptual model is adopted. The regional tectonic movement and the corresponding fracture system are dynamically analyzed to determine the possibility of multi-stage fracture development and the development characteristics of each stage of fracture system from the perspective of genesis. This guides fracture prediction in core, imaging logging, and especially seismic data, reducing the ambiguity of fracture prediction and eliminating erroneous predictions of small and medium-scale fractures caused by poor seismic data quality.

[0101] 2) Localization analysis of dynamic fracture model. Based on the major tectonic movements in the region, the development characteristics of the structural patterns of the main parts of the salt dome under the action of the main tectonic stress field were innovatively analyzed. This decomposed the unique dynamic change patterns of multi-stage fractures within the salt dome region, realizing the localization of the dynamic fracture model and laying the foundation for subsequent fracture identification of the target layer.

[0102] 3) One-dimensional small-scale fracture model. Through analysis of rock core and imaging logging data, a dynamic model of small-scale fractures at control points (well points) in the salt dome area was established, which characterized the development law of small-scale fractures at different locations in the salt dome and effectively supplemented the dynamic fracture conceptual model.

[0103] 4) Four-dimensional fracture identification based on multiple seismic attributes. An innovative four-dimensional fracture analysis method combining forward and reverse time series is established. Reverse time series analysis (from newest to oldest) is carried out on multiple tectonic movements, and the development law of the multi-phase fracture system in three-dimensional space is decomposed using multiple seismic attributes. For the target layer, forward time series analysis (from oldest to newest) is carried out, and the multi-phase fracture system is superimposed to identify the fracture evolution and development law in the target layer.

[0104] This invention also provides a storage medium storing a program that, when executed by a processor, implements a method for identifying cracks in salt dome development areas.

[0105] This invention also provides a processor for running a program, wherein the program executes a crack identification method for salt dome development regions.

[0106] This invention also provides a device, which may include a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it implements the various steps of the above-described method for identifying cracks in salt dome development areas. The device described herein may be a server, PC, PAD, mobile phone, etc.

[0107] This application also provides a computer program product that, when executed on a data processing device, is adapted to perform the steps of initializing the crack identification method for salt dome development areas as described above.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0113] 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.

[0114] Computer-readable media include both permanent and non-permanent, removable and non-removable media that can store information by 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 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.

[0115] 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.

[0116] 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 identifying cracks in a salt dome development area, characterized in that, Crack identification methods include: A regional dynamic fracture model is established based on the tectonic movements of the target region and the fracture system formed by each tectonic movement. Based on the interpretation of 3D seismic data volumes of local geological strata, the regional dynamic fracture model is updated locally. Based on the locally updated regional dynamic fracture model, a reverse dynamic analysis is performed on various tectonic movements and the resulting fracture systems within the target area to identify individual fracture systems generated by each tectonic movement at its corresponding geological strata and to establish a fracture development model of the individual fracture systems over time; and Based on the fracture development model, a forward overlay analysis of the fracture system within the target segment is performed using a multi-scale fracture model fusion approach. This analysis aims to identify the fracture systems generated by various tectonic movements within the target segment, as well as the distribution, development intensity, and development direction of these fracture systems within the salt dome development area. The multi-scale crack model includes: A one-dimensional microfracture model based on rock core and imaging logging data is used to identify fractures smaller than or equal to a first-scale threshold; and A mesoscale crack model based on four-dimensional analysis of multiple seismic attributes is used to identify cracks larger than the first scale threshold.

2. The crack identification method according to claim 1, characterized in that, The one-dimensional microcrack model is established through the following steps: Based on the fracture development parameters of the rock core in the set characteristic well, an initial one-dimensional fracture model is established under the constraints of the regional dynamic fracture model, wherein the fracture development parameters include longitudinal development intensity and fracture angle. The initial one-dimensional fracture model is updated by cross-comparing the fracture development parameters of rock cores from multiple characteristic wells to obtain a first updated model. Based on the imaging logging data from the plurality of characteristic wells, the first update model is updated a second time to obtain a second update model; and The direction of the maximum principal stress in the second updated model is input into the regional dynamic crack model for verification, and the second updated model that passes the verification is determined as the one-dimensional microcrack model.

3. The crack identification method according to claim 1, characterized in that, The process of establishing a regional dynamic fracture model based on the tectonic movements of the target region and the fracture system formed by these movements includes: By analyzing the structural plates, the structural motion unit in which the target region is located is determined; Plate seismic sequence analysis is performed on the tectonic movement units to determine the tectonic movements within the target area; Through structural geomechanical analysis, the fracture systems formed by various tectonic movements and their characteristic parameters are identified. These characteristic parameters include fracture development direction, fracture strength, and distribution range. Based on the tectonic motion and the characteristic parameters of the fracture system, a dynamic fracture model for the region is established.

4. The crack identification method according to claim 1 or 3, characterized in that, The structural motion includes one or more of the following: fracture tension motion, slip-slip tension motion, and compression motion.

5. The crack identification method according to claim 1, characterized in that, The interpretation of the three-dimensional seismic data volume based on local geological strata, and the localization update of the regional dynamic fracture model, include: Based on the interpretation of the three-dimensional seismic data volume, the effect of the tectonic movement on the local geological strata is determined, so as to obtain the geological structure map of the local geological strata; In the local geological strata, the geological strata after the tectonic movement were selected and flattened to restore the paleogeographic morphology of the geological strata. Seismic profiles penetrating the salt dome are selected from the three-dimensional seismic data volume to obtain the tectonic high points and dynamic changes in stratigraphic thickness of the salt dome; and Based on the geological structure map of the local geological strata, the paleogeomorphology of the geological strata, and the seismic profile of the salt dome, the regional dynamic fracture model is updated locally.

6. The crack identification method according to claim 1 or 5, characterized in that, The three-dimensional seismic data volume includes one or more of the following: chaotic volume, curvature volume, variance volume, and ant volume.

7. The crack identification method according to claim 1, characterized in that, After performing forward superposition analysis of the fracture system within the target segment based on the fracture development model using a multi-scale fracture model fusion approach, the fracture identification method further includes: The identified fracture development is verified based on the production well reservoir production data within the target area.

8. A crack identification system for salt dome development areas, characterized in that, The crack identification system includes: The model building device is used to establish a regional dynamic crack model based on the tectonic movements of the target area and the fracture system formed by each tectonic movement. A localization update device is used to perform localization updates on the regional dynamic fracture model based on the interpretation of three-dimensional seismic data volumes according to local geological strata. A reverse dynamic analysis device is used to perform reverse dynamic analysis on various tectonic movements and the resulting fracture systems within the target area based on a locally updated regional dynamic fracture model. This analysis aims to identify individual fracture systems generated by each tectonic movement at its corresponding geological strata and to establish a temporal fracture development model for each individual fracture system. The forward superposition analysis device is used to perform forward superposition analysis on the fracture system within the target layer based on the fracture development model, using a multi-scale fracture model fusion approach. This analysis aims to identify the fracture systems generated by various tectonic movements within the target layer, as well as the distribution location, development intensity, and development direction of these fracture systems within the salt dome development area. The multi-scale crack model includes: A one-dimensional microfracture model based on rock core and imaging logging data is used to identify fractures smaller than or equal to a first-scale threshold; and A mesoscale crack model based on four-dimensional analysis of multiple seismic attributes is used to identify cracks larger than the first scale threshold.

9. A machine-readable storage medium, characterized in that, The machine-readable storage medium stores instructions for causing the machine to perform: a method for identifying cracks in a salt dome development area according to any one of claims 1-7.

Images