Fracture identification method and identification system for salt hill development area and storage medium

Abstract

The invention provides a crack identification method and identification system for a salt hill development area and a storage medium, and belongs to the field of geological exploration. Comprising the following steps: establishing a regional dynamic crack model and carrying out localization updating on the regional dynamic crack model; performing reverse dynamic analysis on each tectonic motion in the target area and a formed fracture system to identify a single fracture system generated by each tectonic motion in a corresponding geologic horizon and establish a fracture development model of each tectonic motion in a time dimension; and performing forward superposition analysis on the crack system in the target layer section based on the crack development model in a multi-scale crack model fusion mode to identify the crack system generated by each tectonic movement in the target layer section and the distribution position, development intensity and development direction of the crack system. According to the method, the dynamic fracture model and positive and negative time sequence combined four-dimensional fracture prediction is adopted, and multi-scale fracture model fusion is combined, so that complex and changeable fracture development styles of different parts of the salt hill can be accurately revealed, and data support is provided for subsequent oil reservoir development and horizontal well design.

Description

Technical Field

[0001] The present invention relates to the field of geological exploration technology, and in particular to a crack identification method, an identification system and a storage medium in a salt dome development area. Background Art

[0002] In salt dome regions, the overlying dense carbonate rocks, under the influence of multiple (or more than two) tectonic movements, form unique and extremely complex fracture systems. These fractures are characterized by the overlapping of multiple fractures with different development directions and intensities, controlled by different tectonic movements. Due to the presence of salt domes, these overlapping fractures exhibit completely different developmental characteristics in salt dome areas compared to those in non-salt dome areas. These characteristics place new demands on fracture prediction, and conventional fracture prediction methods are no longer sufficient in salt dome regions.

[0003] Currently developed technologies for predicting fractures in carbonate reservoirs include shear wave splitting, longitudinal wave AVAZ (Amplitude Versus Azmuith Anisotropy), and multi-attribute seismic attribute fusion. However, multi-component seismic acquisition and processing are expensive and relatively rarely used. Longitudinal wave AVAZ technology is another effective seismic fracture prediction technique, but it requires wide-azimuth seismic data and targeted processing techniques, which limits its application. Multi-attribute seismic attribute fusion is currently a widely used fracture prediction technique for carbonate reservoirs. While this method can generally meet the requirements for fracture prediction, its main drawbacks are that it is limited by the resolution of the seismic data and cannot identify small-scale fractures. For medium-scale fractures, data quality is severely limited. Without other data support, it is often impossible to determine whether a fracture is noise or signal, significantly reducing the accuracy of small and medium-scale predictions.

[0004] In summary, in salt dome areas affected by multi-phase tectonic movements, multiple groups of fractures change dynamically and overlap, which places higher demands on fracture identification and prediction methods. Existing technologies are not yet sufficient to solve this problem. Summary of the Invention

[0005] The present invention provides a fracture identification method, an identification system, and a storage medium for salt dome development areas. A unique prediction method is adopted for multiple groups of fractures in salt dome development areas. The purpose is to identify the dynamic changes of multiple groups of fractures in the target reservoir in the salt dome development area under the influence of multi-phase tectonic movement, characterize the direction and development intensity of the fractures, and predict the spatial distribution of the fractures, thereby providing data support for the subsequent development of rock reservoirs and the layout of horizontal wells.

[0006] An embodiment of the present invention aims to provide a method for identifying fractures in a salt dome development area. The method comprises: establishing a regional dynamic fracture model based on tectonic movements in a target area and fracture systems formed by each tectonic movement; locally updating the regional dynamic fracture model based on interpretation of three-dimensional seismic data of local geological layers; 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 to identify a single fracture system generated by each tectonic movement in its corresponding geological layer and establish a fracture development model of the single fracture system in the time dimension; and performing forward superposition analysis on the fracture system in the target layer segment by fusion of multi-scale fracture models based on the fracture development model to identify the fracture system generated by each tectonic movement in the target layer segment and the distribution position, development intensity, and development direction of the fracture system in 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 less 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 greater than the first scale threshold.

[0008] Optionally, the one-dimensional microfracture model is established by 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 first updated by cross-comparing the development fracture parameters of the rock cores in multiple characteristic wells to obtain a first updated model; the first updated model is second updated according to the imaging logging data in the multiple characteristic wells to obtain a second updated model; and the maximum principal stress direction 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, the regional dynamic fracture model is established based on the tectonic movement in the target area and the fault system formed by each tectonic movement, including: determining the tectonic movement unit in the target area through tectonic plate analysis; performing plate seismic sequence analysis on the tectonic movement unit to determine the various tectonic movements in the target area; identifying the fault system formed by each tectonic movement and its characteristic parameters through tectonic geomechanics analysis, wherein the characteristic parameters include fault development direction, fault strength and distribution range; and establishing the regional dynamic fracture model based on the tectonic movement and the characteristic parameters of the fault system.

[0010] Optionally, the tectonic movement includes one or more of the following: fracture extension movement, strike-slip extension movement, and compression movement.

[0011] Optionally, the interpretation of the three-dimensional seismic data volume based on the local geological layer is used to locally update the regional dynamic fracture model, including: determining the effect of the tectonic movement on the local geological layer based on the interpretation of the three-dimensional seismic data volume to obtain a geological structure map of the local geological layer; selecting a geological layer after the tectonic movement occurs in the local geological layer for leveling operation to restore the paleogeomorphology of the geological layer; selecting a seismic profile passing through the salt dome from the three-dimensional seismic data volume to obtain the structural highs and dynamic changes in the thickness of the salt dome; and locally updating the regional dynamic fracture model based on the geological structure map of the local geological layer, the paleogeomorphology of the geological layer, and the seismic profile of the salt dome.

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

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

[0014] On the other hand, the present invention also provides a fracture identification system for a salt dome development area, the fracture identification system comprising: a model building device for establishing a regional dynamic fracture model based on the tectonic movement of the target area and the fracture system formed by each tectonic movement; a localization updating device for locally updating the regional dynamic fracture model based on the three-dimensional seismic data interpretation of the local geological layer; a reverse dynamic analysis device for performing reverse dynamic analysis on the tectonic movements 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 layer 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 layer segment in a multi-scale fracture model fusion manner based on the fracture development model, so as to identify the fracture system generated by each tectonic movement in the target layer segment and the distribution position, development intensity and development direction of the fracture system in the salt dome development area.

[0015] On the other hand, the present application provides a machine-readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute: the fracture identification method for salt dome development areas described above.

[0016] Through the above technical solution, the present 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 four-dimensional fracture prediction method based on a combination of forward and reverse time series guided by a dynamic fracture concept model and a comprehensive analysis of multidisciplinary data. Combined with the fusion of multi-scale fracture models, the fractures of different scales in different parts of the salt dome development area are mutually verified. This can more accurately reveal the complex and changeable fracture development patterns in different parts of the salt dome, and can 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 subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings: Figure 1 This is a flow chart of a method for identifying fractures in a salt dome development area according to an embodiment of the present application; Figure 2 Schematic diagram of a dynamic crack prediction workflow according to an embodiment of the present application; Figure 3 Schematic diagram of the target layer segment fracture prediction process according to an embodiment of the present application; Figure 4 A schematic diagram of a regional dynamic fracture conceptual model according to an embodiment of the present application is provided; Figures 5a-5c Schematic diagram of the localization process of the fracture conceptual model according to an embodiment of the present application; Figure 6 Schematic diagram of a conceptual model of a crack according to an embodiment of the present application; Figure 7 Schematic diagram of four-dimensional fracture identification and time-reverse multi-period fracture system decomposition according to an embodiment of the present application; Figure 8 Schematic diagram of multi-stage fracture identification in a salt dome area according to an embodiment of the present application; Figure 9 Schematic diagram of core data analysis according to an embodiment of the present application; Figure 10 Schematic diagram of the relationship between imaging logging analysis - fracture azimuth & dip and salt dome according to an embodiment of the present application; Figure 11 Schematic diagram of the structure of a fracture identification system for a salt dome development area according to an embodiment of the present application. DETAILED DESCRIPTION

[0019] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0020] Paleozoic salt domes and salt diapirs are widely developed in the southwestern Persian Gulf. The applicant found that in salt dome areas, four-way closed structures often appear in the overlying layers of salt domes, forming a structural closure. Under the action of multiple phases of tectonic movement, the overlying dense carbonate rock has formed a multi-phase complex and variable fracture system. Due to the existence of salt dome structures, multiple phases of tectonic movement have formed a fracture structure style in the salt dome area that is completely different from that in non-salt dome areas. This particularity is manifested in different parts of the salt dome structure. The structural style is different, and the fracture system development scale, direction, strength and closure are all different, which puts higher demands on conventional fracture prediction and identification methods.

[0021] It can be seen that for salt dome development areas, there is a problem of identifying multi-stage fractures in the overlying dense carbonate rocks. To this end, the present 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. Figure 1 As shown, the crack identification method 100 may include steps S110-S140. The specific dynamic crack prediction workflow diagram can be found in Figure 2 and Figure 3 shown.

[0022] Step S110 : establishing a regional dynamic fracture model based on the tectonic movements in the target area and the fracture systems formed by the tectonic movements.

[0023] In one embodiment, step S110 may include steps S111-S114: Step S111: determining the tectonic movement unit where the target area is located through tectonic plate analysis.

[0024] First, through tectonic plate analysis, the tectonic movement unit where the target area is located can be determined, for example, the Arabian plate in this embodiment.

[0025] Step S112: performing plate seismic sequence analysis on the tectonic movement unit to determine various tectonic movements in the target area.

[0026] Specifically, if Figure 4As shown, ophiolite data analysis and plate seismic sequence analysis can be conducted to determine the main tectonic movements in the region. Tectonic movements can include one or more of the following: fracture extension, strike-slip extension, and compression. In this embodiment, the tectonic movements in the target region can be determined as: fracture extension in the Jurassic, strike-slip extension in the Cretaceous, and compression in the Tertiary.

[0027] Step S113: Identify the fault systems and characteristic parameters formed by various tectonic movements through structural geomechanics analysis.

[0028] Specifically, structural geomechanical analysis can be performed to identify the corresponding fault system and its key characteristic parameters formed by each tectonic movement. Among them, key characteristic parameters may include fault development direction, fault strength, and main distribution range and characteristics.

[0029] Step S114: establishing a regional dynamic fracture model based on the characteristic parameters of the tectonic movement and the fracture system.

[0030] Specifically, a regional dynamic fracture model can be established based on the characteristic parameters of tectonic movement and fault system. Figure 4 As shown in the figure, first, a dynamic relationship between the main tectonic movements (such as the fault-extensional movement in the Jurassic, the strike-slip extensional movement in the Cretaceous, and the compressional movement in the Tertiary) and the landmark stratigraphic series (the Jurassic Arabian Formation, the Cretaceous Mishrif Formation, and the Tertiary Rus Formation) is established vertically; second, on the basis of the dynamic relationship, the dynamic evolution of fractures within a single landmark formation and the temporal evolution of fractures based on multiple sets of landmark formations are identified, thus finally forming a regional dynamic fracture conceptual model.

[0031] One of the key points of the present invention is the use of a dynamic fracture concept model, which can dynamically analyze regional tectonic movements and the corresponding fracture systems, determine the possibility of multi-stage fracture development and the development characteristics of each fracture system from the perspective of genesis, and guide fracture prediction based on core and imaging logging, especially seismic data, thereby reducing the multi-solution nature of fracture prediction and eliminating erroneous predictions of small and medium-sized fractures caused by poor quality seismic data.

[0032] Step S120 : performing localized update on the regional dynamic fracture model based on the interpretation of the 3D seismic data volume of the local geological layer.

[0033] Among them, see Figures 5a-5c The local data of the local geological layer mainly refers to the geological structure map, seismic profile, paleo-geomorphology map, etc. generated based on the seismic data. This step is to locally update the regional dynamic fracture model based on the geological structure map, seismic profile, and paleo-geomorphology map generated by the seismic data.

[0034] In one embodiment, step S120 may include steps S121-S124: Step S121 : Based on the interpretation of the 3D seismic data volume, determine the effect of tectonic movement on the local geological layer to obtain a geological structure map of the local geological layer.

[0035] Specifically, under the guidance of the regional fracture concept model, parameters that conform to the fracture concept model are preferably selected to generate a variety of 3D seismic attribute volumes, mainly including but not limited to chaos volume, curvature volume, variance volume, and ant volume. That is, the 3D seismic data volume can include one or more of the following: chaos volume, curvature volume, variance volume, and ant volume. Then, the 3D seismic data can be interpreted to generate a structural top surface map of key geological layers from shallow to deep, such as Figure 5a Furthermore, the dynamic changes of structural morphology are analyzed, especially the evolution of structural morphology during the main tectonic movement period, so as to determine the effect of tectonic movement on local geological layers and adjust and optimize the regional fracture conceptual model.

[0036] Step S122 : Select a geological layer after the tectonic movement occurs in the local geological layer and perform a leveling operation to restore the paleo-geomorphology of the geological layer.

[0037] Specifically, if Figure 5b As shown, local paleo-tectonic restoration can be performed. Focusing on the geological period during which major tectonic movements occurred, the geological horizons before and after the tectonic movements are flattened to restore the paleo-geomorphology of these geological horizons. The local structural pattern of the tectonic movement, the corresponding fault system characteristics, and the differences with the regional fracture conceptual model can then be analyzed, and the model can be updated using this data.

[0038] Paleotectonic restoration involves flattening specific geological horizons. In practical applications, two factors must be considered when selecting geological horizons: the flattened horizons should be as close as possible to the target horizons; and to minimize the impact of subsequent tectonic movements, the horizons should be selected from sedimentary strata from a relatively stable period with minimal tectonic movement.

[0039] Step S123 : selecting a seismic profile that passes through the salt dome from the 3D seismic data volume to obtain the structural highs of the salt dome and the dynamic changes in the stratum thickness.

[0040] Specifically, if Figure 5c As shown, it is necessary to select a seismic profile that passes through the salt dome from the 3D seismic data volume, and then analyze the dynamic changes of structural highs and stratum thickness to further determine the intensity of tectonic movement and the relationship between the corresponding fracture distribution and salt dome.

[0041] In practical applications, salt domes are generally known. The specific penetration method depends on the salt dome's morphology, with two common options: one perpendicular to the salt dome's strike and one parallel to it. The thickness of a salt dome generally indicates strong tectonic activity, as high-intensity tectonic activity can create large spaces (basins) for sediment deposition and thick strata. Similarly, the height of a salt dome's high points can also reflect the strength of tectonic activity.

[0042] Step S124 : performing a localized update on the regional dynamic fracture model based on the geological structure map of the local geological layer, the paleo-geomorphology of the geological layer, and the seismic profile of the salt dome.

[0043] Specifically, combined with the above data obtained in steps S121-123, including the geological structure map of the local geological layer, the paleogeomorphology of the geological layer, and the seismic profile of the salt dome, the regional dynamic fracture model can be localized and updated to obtain Figure 6 The updated fracture conceptual model is shown.

[0044] Through the above steps, the present invention can innovatively analyze the structural style 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, thereby decomposing the dynamic change laws unique to multi-stage fractures in the salt dome area, performing relatively high-precision analysis in the target area, and realizing the localization of the dynamic fracture model, laying the foundation for subsequent fracture identification in the target layer segment.

[0045] In step S130, based on the locally updated regional dynamic fracture model, reverse dynamic analysis is performed on the various tectonic movements and the resulting fracture systems in the target area to identify the single fracture systems generated by each tectonic movement in its corresponding geological layer and to establish a fracture development model of the single fracture system in the time dimension.

[0046] Specifically, the seismic attribute data of the geological layers corresponding to the main tectonic movements can be extracted. In this example, from oldest to youngest, they are the Jurassic Arabian Formation, the Cretaceous Mishrif Formation, and the Tertiary Rus Formation. In this step, it is necessary to conduct a reverse dynamic analysis (in reverse chronological order) of the main tectonic movements (fault extension movement in the Jurassic, strike-slip extension movement in the Cretaceous, and compression movement in the Tertiary) and the resulting fracture systems, from shallow to deep and from young to old, to establish a fracture development model of a single fracture system related to the tectonic movement in the time dimension (the fourth dimension), such as Figure 7 That is, the directional dynamic analysis in this step is in reverse chronological order, analyzing the characteristics of a series of local tectonic movements from new to old, as well as the development of the corresponding fault systems (cracks), thereby identifying the main (single) cracks and their characteristics generated by each tectonic movement in its corresponding geological layer (i.e., the geological layer closest to the current tectonic movement).

[0047] The purpose of this step is to achieve four-dimensional fracture identification in the target area based on multiple seismic attributes. Specifically, within the constraints of the aforementioned dynamic fracture model, the present invention can add additional control variables to the four-dimensional fracture identification method based on multiple seismic attributes, enabling better identification of fracture distribution within the target area. Generally speaking, fracture size is unrelated to development time and is determined solely by the magnitude of the forces acting on the formation.

[0048] Then, the above analysis process is repeated for the main tectonic movements in the target area, and a forward superposition analysis (time sequence) is performed on the fracture system in the target layer to identify the dynamic changes and development characteristics of the fractures in the salt dome area. See step S140 for details.

[0049] Step S140: Based on the fracture development model, a forward superposition analysis is performed on the fracture system in the target layer segment by fusion of multi-scale fracture models to identify the fracture system generated by each tectonic movement in the target layer segment and the distribution position, development intensity and development direction of the fracture system in the salt dome development area.

[0050] That is to say, based on the reverse dynamic analysis in step S130 to clarify the characteristics of the tectonic movement in the work area, this step S140 further forward analyzes the development of cracks generated by each tectonic movement in the target layer, such as Figure 8 That is, under the guidance of the dynamic fracture model, the present invention can eliminate coherent noise from the seismic attribute volume of the target layer segment, identify the fracture system generated by various tectonic movements in the target layer, that is, various (multiple) fractures and their characteristics, and simultaneously identify the distribution location, development intensity, and development direction of the fracture system in the salt dome area.

[0051] In summary, this invention utilizes four-dimensional fracture identification based on multiple seismic attributes. This innovative four-dimensional fracture analysis method combines forward and reverse time series analysis. This method performs a reverse time series analysis (from newest to oldest) of multiple tectonic movements, using multiple seismic attributes to decompose the development patterns of these multi-period fracture systems in three dimensions. A forward time series analysis (from oldest to newest) is then performed on the target horizon, overlaying the multi-period fracture systems to identify fracture evolution and development patterns within the target interval.

[0052] Furthermore, due to the limited resolution of seismic data, only large-scale and medium-scale fractures can generally be identified. Large-scale fractures or faults are distinct and relatively easy to identify, while medium-scale fractures, due to their size approaching the seismic wavelength, are more fuzzy and easily confused with noise, making their identification heavily dependent on the seismic data itself. In salt dome reservoirs, influenced by multiple phases of tectonic movement, multiple groups of fractures exhibit even more complex characteristics in salt dome development areas, making them nearly indistinguishable from coherent noise in seismic data.

[0053] To this end, the present 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, building on a fracture concept model based on regional and local tectonic evolution analysis. By integrating the multi-scale fracture models, different scale fractures in different parts of salt domes in salt dome development areas are cross-validated to identify the spatial distribution, fracture angles, and development intensity of multiple groups of fractures within tight carbonate reservoirs. In one embodiment, the multi-scale fracture model may include: 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. In other words, it can be used to identify small-scale fractures. Generally, small-scale fractures are smaller than a meter, so the first scale threshold can be defined as 1-10 meters. Preferably, small-scale fractures are ≤1 meter or ≤10 meters.

[0054] 2) A mesoscale fracture model based on four-dimensional analysis of multiple seismic attributes can be used to identify fractures larger than a first scale threshold. In other words, it can be used to identify medium- to large-scale fractures. Generally speaking, 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, mesoscale fractures are on the order of 1-10m or 10-1000m.

[0055] Specifically, a one-dimensional microcrack model can be established by the following steps: 1) 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. Fracture development parameters can include longitudinal development intensity and fracture angle.

[0056] This step is to select a characteristic well and use its rock core data to build a preliminary model. Figure 9 As shown in the figure, a preliminary one-dimensional small-scale fracture model is constructed based on the rock core data. Specifically, small-scale fractures can be identified in the rock core at the well point location of the set feature well (exploration well) for key geological layers corresponding to major tectonic movements. Under the constraints of the fracture model established in the previous step, the initial one-dimensional small-scale fracture model is established by combining the calculated vertical development intensity (density) and fracture angle of the rock core fractures.

[0057] 2) By cross-comparing the developed fracture parameters of rock cores in multiple characteristic wells, the initial one-dimensional fracture model is first updated to obtain a first updated model.

[0058] This step involves selecting multiple characteristic wells for cross-comparison, thereby updating the aforementioned model. Specifically, small-scale fractures identified in the cores of these characteristic wells can be cross-compared. Based on their lateral positions, the relationship between fracture development and different parts of the salt dome can be analyzed, thereby performing a first update on the initial one-dimensional fracture model to obtain a first updated model.

[0059] It should be noted that the fractures in multiple characteristic wells are more of spatial control points, while the prediction of fractures between well points still relies more on seismic data.

[0060] 3) performing a second update on the first updated model based on the imaging logging data in the plurality of characteristic wells to obtain a second updated model.

[0061] This step is to update the model again based on the imaging logging data of multiple feature wells. Figure 10 The figure below shows an update of a one-dimensional, small-scale fracture model based on imaging logging data. Imaging logging data requires the use of multiple feature wells because fractures at different locations have different characteristics. Therefore, multiple points can be used as positioning points to achieve planar control of the study area.

[0062] Specifically, microfracture (small-scale) analysis based on imaging logging data can be conducted at wellpoint locations to identify the fracture orientation, angle, and current maximum subsurface principal stress direction. Small-scale fractures (direction and scale) can be directly identified by collecting imaging logging data from exploration wells. It is worth noting that although a well appears as a straight line in three-dimensional space, this does not necessarily mean that the fractures are vertical. Subsequently, fracture identification analysis based on a fracture concept model can be performed. While variations in imaging logging data quality can lead to multiple solutions for fracture identification, within the constraints of the fracture concept model, the present invention can identify fractures that conform to geomechanical and geological laws. Finally, the microfracture information identified based on imaging logging analysis can be updated into a one-dimensional small-scale fracture model, thereby controlling the microfracture distribution patterns in the salt dome region at the wellpoint location. In other words, through the aforementioned analysis of rock core and imaging logging data, the present invention can establish a dynamic model of small-scale fractures at control points (wellpoints) in the salt dome region, thereby characterizing the development patterns of small-scale fractures at different locations in the salt dome and effectively complementing the dynamic fracture concept model.

[0063] 4) The maximum principal stress direction in the second updated model is input into the regional dynamic crack model for verification, and the verified second updated model is determined as a one-dimensional microcrack model.

[0064] This step verifies the consistency of the principal stress directions. If verified, the model is used for small crack identification. Specifically, the identified maximum principal stress direction can be used to cross-validate the dynamic crack concept model. In this example, based on induced fracture analysis, the current maximum principal stress direction in the second updated model is NE-SW, while the most recent Tertiary principal stress direction in the crack model is also NE-SW compression. This indicates that the principal stress directions are consistent, thus confirming the verification of the dynamic crack concept model.

[0065] Through the above technical solution, the present invention provides a method for predicting multi-stage fractures in salt dome-developed areas, particularly tight carbonate reservoirs. This method utilizes a four-dimensional fracture prediction method based on a dynamic fracture conceptual model, combined with forward and reverse time series analysis and multidisciplinary data analysis, to identify and predict the spatial distribution and development intensity of multi-stage fractures in the reservoir overlying the salt dome. This method, for the first time, proposes a four-dimensional fracture prediction method based on a dynamic fracture model in salt dome-developed 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.

[0066] In one embodiment, after step S140, the fracture identification method 100 of the present invention may further include step S150 of verifying the identified fracture development based on reservoir production data from production wells within the target area. Specifically, reservoir analysis of production wells within the target area may reveal that, due to low reservoir matrix permeability, reservoir production is normally limited. However, analysis of actual test data reveals significant reservoir production, indirectly corroborating the fracture development characteristics. In other words, the test data demonstrates the contribution of fracture development to production in tight carbonate reservoirs.

[0067] Through the above technical solution, the present invention can achieve the following beneficial effects: 1) Adopting a dynamic fracture concept model. This model dynamically analyzes regional tectonic movements and the corresponding fracture systems, determining the possibility of multi-stage fracture development and the development characteristics of each fracture system based on their genesis. This model guides fracture prediction using core and imaging logging data, especially seismic data, reduces the potential for multiple solutions and eliminates mispredictions of small and medium-sized fractures caused by poor seismic data quality.

[0068] 2) Localized analysis of dynamic fracture models. Based on the main tectonic movements in the region, we innovatively analyzed the structural development characteristics of the main salt dome locations under the influence of the main tectonic stress fields. This allowed us to decompose the unique dynamic variation patterns of multi-stage fractures within the salt dome region, localize the dynamic fracture model, and lay the foundation for subsequent fracture identification in the target layer.

[0069] 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 region was established. This model characterizes the development patterns of small-scale fractures at different locations in the salt dome and effectively supplements the dynamic fracture conceptual model.

[0070] 4) Four-dimensional fracture identification based on multiple seismic attributes. An innovative four-dimensional fracture analysis method combining forward and reverse time series analysis was established. Reverse time series analysis (from newest to oldest) of multiple tectonic movements was performed, using multiple seismic attributes to decompose the development patterns of multi-period fracture systems in three-dimensional space. Forward time series analysis (from oldest to newest) of target layers was performed, and the multi-period fracture systems were superimposed to identify the fracture evolution and development patterns within the target interval.

[0071] On the other hand, the present invention also provides a fracture identification system 200 in a salt dome development area, such as Figure 11 As shown, the crack identification system 200 may include: The model building device 210 is used to build a regional dynamic fracture model based on the tectonic movements in the target area and the fracture systems formed by each tectonic movement.

[0072] The localized updating device 220 is used to perform localized updating on the regional dynamic fracture model based on the interpretation of the 3D seismic data volume of the local geological layer.

[0073] The reverse dynamic analysis device 230 is used to perform reverse dynamic analysis on the various tectonic movements and the resulting fracture systems in the target area based on the locally updated regional dynamic fracture model, so as to identify the single fracture systems generated by each tectonic movement in its corresponding geological layer and establish a fracture development model of the single fracture system in the time dimension.

[0074] The forward superposition analysis device 240 is used to perform forward superposition analysis on the fracture system in the target layer segment based on the fracture development model by fusing a multi-scale fracture model, so as to identify the fracture system generated by each tectonic movement in the target layer segment and the distribution position, development intensity and development direction of the fracture system in the salt dome development area.

[0075] 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 less 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 greater than the first scale threshold.

[0076] In one embodiment, the one-dimensional microfracture model is established by 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 first updated by cross-comparing the development fracture parameters of the rock cores in multiple characteristic wells to obtain a first updated model; based on the imaging logging data in the multiple characteristic wells, the first updated model is second updated to obtain a second updated model; and the maximum principal stress direction 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.

[0077] In one embodiment, the model building device 210 can be specifically used to perform the following: determining the tectonic movement unit in which the target area is located through tectonic plate analysis; performing plate seismic sequence analysis on the tectonic movement unit to determine the various tectonic movements in the target area; identifying the fault systems formed by various tectonic movements and their characteristic parameters through tectonic geomechanics analysis, wherein the characteristic parameters include the direction of fault development, fault strength and distribution range; and establishing the regional dynamic fracture model based on the characteristic parameters of the tectonic movement and the fault system.

[0078] In one embodiment, the tectonic movement includes one or more of the following: fracture extension movement, strike-slip extension movement, and compression movement.

[0079] In one embodiment, the localization update device 220 can be specifically used to perform: based on the interpretation of the three-dimensional seismic data body, determine the effect of the tectonic movement on the local geological layer to obtain the geological structure map of the local geological layer; select the geological layer after the tectonic movement occurs in the local geological layer for leveling operation to restore the paleogeomorphology of the geological layer; select the seismic profile passing through the salt dome from the three-dimensional seismic data body to obtain the structural high point and dynamic change of the stratum thickness of the salt dome; and based on the geological structure map of the local geological layer, the paleogeomorphology of the geological layer, and the seismic profile of the salt dome, perform localized update of the regional dynamic fracture model.

[0080] In one embodiment, the 3D seismic data volume includes one or more of the following: a chaos volume, a curvature volume, a variance volume, and an ant volume.

[0081] In one embodiment, the fracture identification system 200 further includes: a verification device for verifying the development of the identified fractures based on the reservoir production data of the production wells in the target area.

[0082] Through the above technical solution, the present invention can achieve the following beneficial effects: 1) Adopting a dynamic fracture concept model. This model dynamically analyzes regional tectonic movements and the corresponding fracture systems, determining the possibility of multi-stage fracture development and the development characteristics of each fracture system based on their genesis. This model guides fracture prediction using core and imaging logging data, especially seismic data, reduces the potential for multiple solutions and eliminates mispredictions of small and medium-sized fractures caused by poor seismic data quality.

[0083] 2) Localized analysis of dynamic fracture models. Based on the main tectonic movements in the region, we innovatively analyzed the structural development characteristics of the main salt dome locations under the influence of the main tectonic stress fields. This allowed us to decompose the unique dynamic variation patterns of multi-stage fractures within the salt dome region, localize the dynamic fracture model, and lay the foundation for subsequent fracture identification in the target layer.

[0084] 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 region was established. This model characterizes the development patterns of small-scale fractures at different locations in the salt dome and effectively supplements the dynamic fracture conceptual model.

[0085] 4) Four-dimensional fracture identification based on multiple seismic attributes. An innovative four-dimensional fracture analysis method combining forward and reverse time series analysis was established. Reverse time series analysis (from newest to oldest) of multiple tectonic movements was performed, using multiple seismic attributes to decompose the development patterns of multi-period fracture systems in three-dimensional space. Forward time series analysis (from oldest to newest) of target layers was performed, and the multi-period fracture systems were superimposed to identify the fracture evolution and development patterns within the target interval.

[0086] An embodiment of the present invention further provides a storage medium storing a program, which, when executed by a processor, implements a method for identifying fractures in a salt dome development area.

[0087] An embodiment of the present invention further provides a processor, which is used to run a program, wherein the program executes a method for identifying fractures in a salt dome development area when the program is run.

[0088] An embodiment of the present invention further provides a device, which may include a processor, a memory, and a program stored in the memory and executable by the processor. When the processor executes the program, it implements the steps of the aforementioned method for identifying fractures in salt dome development areas. The device herein may be a server, a PC, a PAD, a mobile phone, or the like.

[0089] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program for initializing the steps of the above-mentioned fracture identification method for salt dome development areas.

[0090] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0091] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0092] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0093] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0094] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0095] Memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

[0096] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can be implemented using any method or technology for information storage. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change RAM (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, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices, or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media such as modulated data signals and carrier waves.

[0097] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0098] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A method for identifying fractures in a salt dome development area, characterized in that: Crack identification methods include: Establish a regional dynamic fracture model based on the tectonic movements in the target area and the fracture systems formed by each tectonic movement; Locally update the regional dynamic fracture model based on the interpretation of 3D seismic data volumes at local geological horizons; Based on the locally updated regional dynamic fracture model, reverse dynamic analysis is performed on the various tectonic movements and the resulting fracture systems within the target area to identify the single fracture systems generated by each tectonic movement in its corresponding geological layer and to establish a fracture development model for the single fracture system in the time dimension; and Based on the fracture development model, a forward superposition analysis of the fracture system in the target layer is performed by fusion of multi-scale fracture models to identify the fracture systems generated by various tectonic movements in the target layer, as well as the distribution position, development intensity and development direction of the fracture systems in the salt dome development area.

2. The crack identification method according to claim 1, characterized in that: The multi-scale fracture model includes: A one-dimensional microfracture model based on rock core and image log data 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 is used to identify fractures larger than the first scale threshold.

3. The crack identification method according to claim 2, characterized in that: The one-dimensional microcrack model is established by 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; performing a first update on the initial one-dimensional fracture model by cross-comparing developed fracture parameters of rock cores in a plurality of characteristic wells to obtain a first updated model; performing a second update on the first updated model according to the imaging logging data in the plurality of characteristic wells to obtain a second updated model; and The maximum principal stress direction 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.

4. The crack identification method according to claim 1, characterized in that: The method of establishing a regional dynamic fracture model based on the tectonic movements in the target area and the fracture systems formed by the tectonic movements includes: Determine 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 various tectonic movements within the target area; Identify the fracture systems and their characteristic parameters formed by various tectonic movements through structural geomechanics analysis, where the characteristic parameters include fracture development direction, fracture strength, and distribution range; and The regional dynamic fracture model is established according to the tectonic movement and characteristic parameters of the fracture system.

5. The crack identification method according to claim 1 or 4, characterized in that: The tectonic movement includes one or more of the following: fault extension movement, strike-slip extension movement, and compression movement.

6. The crack identification method according to claim 1, characterized in that: The localized update of the regional dynamic fracture model based on the interpretation of the 3D seismic data volume of the local geological horizon includes: Determining the effect of the tectonic movement on the local geological horizon based on the interpretation of the 3D seismic data volume to obtain a geological structural map of the local geological horizon; Selecting a geological layer after the occurrence of the tectonic movement from the local geological layers and performing a leveling operation to restore the paleo-geomorphology of the geological layer; Selecting a seismic profile that passes through the salt dome from the three-dimensional seismic data volume to obtain the structural highs and dynamic changes in the thickness of the salt dome; and The regional dynamic fracture model is locally updated based on the geological structure map of the local geological layer, the paleo-geomorphology of the geological layer, and the seismic profile of the salt dome.

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

8. The crack identification method according to claim 1, characterized in that: After performing a forward superposition analysis on the fracture system in the target layer by fusion of multi-scale fracture models based on the fracture development model, the fracture identification method further includes: The identified fracture development is verified based on the reservoir production data of production wells in the target area.

9. A fracture identification system for salt dome development areas, characterized in that: The crack identification system comprises: A model building device for building a regional dynamic fracture model based on the tectonic movements in the target area and the fracture systems formed by each tectonic movement; A localized updating device for locally updating the regional dynamic fracture model based on the interpretation of the three-dimensional seismic data volume of the local geological layer; a reverse dynamic analysis device for performing reverse dynamic analysis on the various tectonic movements and the resulting fracture systems within the target area based on the locally updated regional dynamic fracture model, so as to identify the single fracture systems generated by the various tectonic movements in their corresponding geological layers and establish a fracture development model of the single fracture system in the time dimension; and A forward superposition analysis device is used to perform forward superposition analysis on the fracture system in the target layer segment based on the fracture development model in a multi-scale fracture model fusion manner to identify the fracture system generated by various tectonic movements in the target layer segment and the distribution position, development intensity and development direction of the fracture system in the salt dome development area.

10. A machine-readable storage medium, characterized in that The machine-readable storage medium stores instructions for causing a machine to execute the method for identifying fractures in a salt dome development area according to any one of claims 1 to 8.

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