A method and device for predicting near-source tight sandstone gas sweet spots

Abstract

The present invention provides a method and device for predicting near-source tight sandstone gas sweet spots. The method comprises: restoring the regional tectonic evolution history based on existing geological parameters; determining key periods based on the regional tectonic evolution history, including the early main CO2 generation period and the main natural gas generation period; drawing a tight sandstone paleo-tectonic geological map based on the key periods, and delineating the scope of the structural transition superposition zone to obtain the target area; and grading the sandstone within the target area based on the reservoir characteristics and sedimentary facies of the tight sandstone to determine the distribution of tight gas sweet spots. The prediction method provided by the present invention is simple to operate, practical, and efficient, and can quickly and accurately help geologists and oil and gas companies predict the distribution areas of tight sandstone gas sweet spots.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and natural gas exploration and development, and in particular relates to a method and device for predicting near-source tight sandstone gas sweet spots. Background Art

[0002] Near-source tight sandstone gas represents a promising, clean, and highly efficient energy source. Large-scale industrial production has been achieved in the Carboniferous-Permian and Kuqa Jurassic areas of the Ordos Basin, primarily in areas with near-source coal-bearing sandstones. This gas represents a significant component of the region's growing natural gas reserves. Tight sandstone gas holds enormous potential in all major and medium-sized basins in my country. However, the geological conditions for its formation are complex, and multiple phases of tectonic shifts have resulted in complex and diverse structures and widely varying gas production capacities. Currently, production levels of geographically adjacent wells can vary significantly, with high-yield wells rapidly transitioning to non-productive wells. Accurately predicting gas well yields and sweet spots is crucial for tight gas exploration and development.

[0003] Currently, most tight sandstone gas sweet spot prediction efforts focus on evaluating reservoir sweet spots from a reservoir quality perspective using various techniques. These include predicting areas within tight sandstone distributions with relatively good porosity and permeability using sedimentary, diagenetic, and seismic facies, as well as fracture distribution. For example, geophysical-seismic prediction techniques combine sequence stratigraphic theory with effective geophysical methods to predict sweet spots in tight sandstone gas reservoirs. This approach, based on a three-dimensional rock physics template, identifies the rock physical characteristics of the sweet spot reservoir and elastic parameters sensitive to lithology, physical properties, and gas content. These techniques also consider factors such as mineral composition and content, porosity, and gas saturation. However, this seismic approach provides low sweet spot prediction accuracy. Other approaches include multidisciplinary sweet spot screening techniques that integrate seismic, geological, and production dynamics to summarize and predict geological conditions favorable for tight gas sweet spots, including organic matter abundance, brittle mineral content, and structural location, thereby determining whether an area is a potential reservoir. However, this method cannot guarantee prediction success and, more critically, cannot assess the scale and sustainability of well production, nor can it address issues related to reservoir formation.

[0004] Poor reservoir properties, difficulty identifying gas and water, complex sandbody distribution, and strong heterogeneity have hindered the exploration and development of tight gas reservoirs. Therefore, developing a simple, practical, and efficient method for predicting near-source tight sandstone gas sweet spots, which can quickly and accurately help geologists and oil and gas companies predict the distribution of tight sandstone gas sweet spots, has become a pressing issue for those skilled in the art. Summary of the Invention

[0005] The present invention aims to provide a method and apparatus for predicting near-source tight sandstone gas sweet spots. This method integrates dynamic elements such as tectonic structure, sedimentation, hydrocarbon generation, diagenesis, and reservoir formation, enabling prediction and evaluation in multiple dimensions, both spatially and temporally. This method boasts high accuracy and broad applicability, making it suitable not only for exploring the potential of mature exploration areas but also for evaluating less mature exploration areas.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for predicting near-source tight sandstone gas sweet spots, the method comprising:

[0008] Restore the regional tectonic evolution history based on existing geological parameters;

[0009] According to the regional tectonic evolution history, the key periods are determined, including the early CO2 main generation period and the natural gas main generation period;

[0010] Based on the key periods, a dense sandstone paleo-tectonic geological map was drawn, and the scope of the structural conversion superposition zone was delineated to obtain the target area;

[0011] The sandstones in the target area are graded based on the reservoir characteristics and sedimentary facies of the tight sandstones to determine the distribution of gas sweet spots in the tight sandstones.

[0012] The prediction method provided by the present invention is based on the microscopic mechanism of high-quality reservoir development in tight sandstone gas areas, and at the same time based on the organic-inorganic interaction control of high-quality reservoir development, incorporating the key control and influencing factors of reservoir densification or high-quality reservoir development that can be examined, and incorporating microscopic mechanisms such as the natural gas charging dynamics basis in sweet spot areas for prediction. The tight sandstone gas accumulation law and sweet spot area prediction are comprehensively considered under multi-dimensional conditions such as structure, sedimentation, hydrocarbon generation, diagenesis and accumulation time, and the four histories of regional sedimentary history, structural evolution history, source rock hydrocarbon generation evolution history and accumulation history are integrated into one, thus realizing a multi-dimensional prediction technology for near-source tight sandstone gas sweet spots.

[0013] As a preferred technical solution of the present invention, the existing geological parameters include regional stratum thickness and vitrinite reflectance of terrigenous organic matter in the stratum.

[0014] In the present invention, for areas with relatively mature exploration and geological research, the recognized research results and previous knowledge can be directly used to restore the regional tectonic evolution history; for areas with low exploration levels, the tectonic evolution history in the study area can be restored based on the thickness of the strata revealed by drilling and the maturity of the organic matter therein, and then basin simulation software is used.

[0015] As a preferred technical solution of the present invention, the early CO2 main generation period includes the low maturity stage of kerogen or source rock.

[0016] Preferably, the vitrinite reflectance Ro in the early CO2 main generation period is 0.5%-0.7% and the burial depth is 2000-4000m.

[0017] In the present invention, CO2 has two main generation periods, early and late. The key period of the early CO2 main generation period is when the vitrinite reflectance Ro is between 0.5% and 0.7%. The influence range of the acidic fluid (CO2) during this period determines the high-quality development range of the reservoir.

[0018] As a preferred technical solution of the present invention, the main natural gas generation period includes the following two situations:

[0019] For areas where no uplift or erosion has occurred, the main generation period of natural gas is the present period; or

[0020] In areas where uplift and erosion have occurred, the main generation period of natural gas is the maximum ancient burial period of the source rock layer or tight sandstone.

[0021] In the present invention, the main generation period of natural gas is generally late, and different types of source rocks also have certain differences. For areas where no uplift and erosion have occurred, the present is taken as the key moment of natural gas generation. It is necessary to consider whether an overheating event has occurred in the target area. Generally, the temperature of thermal events is high, and the affected range often corresponds to the maximum paleotemperature.

[0022] As a preferred technical solution of the present invention, the drawing of the dense sandstone paleo-structural geological map includes the following two situations:

[0023] For areas where no uplift and erosion has occurred, the tight sandstone paleo-tectonic geological map shall include a planar distribution map of the paleo-burial depth of target strata during the early main generation period of CO2 and a planar distribution map of the paleo-burial depth of target strata during the main generation period of natural gas; or

[0024] For areas where uplift and erosion have occurred, the dense sandstone paleo-structural geological map includes a planar distribution map of the paleo-burial depth of target strata during the early main CO2 generation period, a planar distribution map of the paleo-burial depth of target strata during the main natural gas generation period, and a planar distribution map of the paleo-burial depth of target strata in the present period.

[0025] In the present invention, the target formation is tight sandstone.

[0026] In the present invention, if an uplift and erosion area has occurred, the structural position and geological map of the current target stratum (tight sandstone) must be considered to consider the effects of the subsequent natural gas preservation, diffusion and migration.

[0027] As a preferred technical solution of the present invention, the scope of the structural transition overlapping area is defined in the following two situations:

[0028] In areas where no uplift and erosion has occurred, a low point range is constructed on the horizontal distribution map of the ancient burial depth of the target stratum during the early main CO2 generation period, and a high point range is constructed on the horizontal distribution map of the ancient burial depth of the target stratum during the main natural gas generation period. The overlapping area of ​​the above two ranges is delineated as the target area; or

[0029] In areas where uplift and erosion have occurred, a low point range is constructed on the plane distribution map of the ancient burial depth of the target strata during the early main CO2 generation period, a high point range is constructed on the plane distribution map of the ancient burial depth of the target strata during the main natural gas generation period, and a high point range is constructed on the plane distribution map of the ancient burial depth of the target strata in the present period. The overlapping area of ​​the above three ranges is delineated as the target area.

[0030] As a preferred technical solution of the present invention, the low point or high point is specifically: the distribution and depth of the dense sandstone relative to the main source rock are at a relatively low point or high point.

[0031] As a preferred technical solution of the present invention, the reservoir characteristics of the tight sandstone include the lithology, mineral composition and sedimentary environment of the sand body itself.

[0032] As a preferred technical solution of the present invention, the result of classifying the sandstone is specifically: in descending order of priority, it is divided into distributary channel sand body, distributary estuary sand bar sand body, distant sand bar sand body, breach fan sand body, beach bar sand body, delta sand body, and lake sand body.

[0033] Preferably, the diversion channel sand body is the best sweet spot.

[0034] In the present invention, the diversion channel sand body is taken as the best sweet spot, and the levels are downgraded in order; from the perspective of lithology, the physical properties of medium-coarse sandstone are significantly better than those of fine sand and siltstone, and the mud matrix content of high-quality reservoirs does not exceed 5%, so clean medium-coarse sandstone is the basis for forming high-quality reservoirs.

[0035] In the present invention, for different levels of sand body classification, priority levels can be divided and drilling can be carried out; at the same time, the gas content in the best sweet spot is relatively high, so the best sweet spot is a favorable area of ​​tight sandstone, and drilling can be carried out in this area for exploration deployment.

[0036] In a second aspect, the present invention provides a prediction device for near-source tight sandstone gas sweet spots, the prediction device comprising:

[0037] The first restoration module is used to restore the regional tectonic evolution history based on existing geological parameters;

[0038] The first determination module is used to determine the key period according to the regional tectonic evolution history, and the key period includes: the early CO2 main generation period and the natural gas main generation period;

[0039] The first drawing module is used to draw a dense sandstone paleo-structural geological map based on key periods, and to delineate the scope of the structural conversion superposition area to obtain the target area;

[0040] The second determination module is used to classify the sandstone in the target area based on the reservoir characteristics and sedimentary facies of the tight sandstone and determine the distribution of gas sweet spots in the tight sandstone.

[0041] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The prediction method provided by the present invention is based on the microscopic mechanisms of high-quality reservoir development in tight sandstone gas areas. It also incorporates key control and influencing factors for reservoir densification or high-quality reservoir development that can be investigated, based on the organic-inorganic interaction control of high-quality reservoir development. It also incorporates microscopic mechanisms such as the foundation of natural gas charging dynamics in sweet spots for prediction. It comprehensively considers tight sandstone gas accumulation patterns and sweet spot predictions based on multidimensional conditions such as structure, sedimentation, hydrocarbon generation, diagenesis, and accumulation time. It integrates the regional sedimentary history, tectonic evolution history, source rock hydrocarbon generation and evolution history, and accumulation history into a single, multidimensional prediction technology for near-source tight sandstone gas sweet spots. Furthermore, the prediction method is simple, practical, and efficient, enabling geologists and oil and gas companies to quickly and accurately predict the distribution areas of tight sandstone gas sweet spots. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Flow chart of the method for predicting near-source tight sandstone gas sweet spots provided in Examples 1 and 2;

[0045] Figure 2 This is a schematic diagram of the structure of the prediction device for near-source tight sandstone gas sweet spots provided in Example 3. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0047] It should be noted that the terms "first", "second", "candidate", "target", etc. in the specification and claims of the present application and the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0048] Example 1

[0049] This embodiment provides a method for predicting near-source tight sandstone gas sweet spots. The selected area is an area that has not undergone uplift and erosion. The prediction method can efficiently and accurately predict the distribution of near-source tight sandstone gas sweet spots. The prediction method can be executed by a near-source tight sandstone gas sweet spot prediction device.

[0050] like Figure 1 As shown, the method provided in this embodiment includes:

[0051] S101. Restore the regional tectonic evolution history based on available geological parameters;

[0052] This example uses a comprehensive analysis of regional stratum thickness and the reflectance of vitrinite of terrigenous organic matter within the stratum to restore the regional tectonic evolution history.

[0053] For areas with relatively mature exploration and geological research, recognized research results can be directly used; for areas with low exploration levels, basin simulation software can be used to restore the tectonic evolution history of the study area based on the thickness of the strata revealed by drilling and the maturity of the organic matter therein.

[0054] S102. Determine key periods based on the regional tectonic evolution history, wherein the key periods include: an early CO2 main generation period and a natural gas main generation period;

[0055] In this embodiment, the early CO2 main generation period includes the low maturity stage of kerogen or source rock; further, the vitrinite reflectance Ro of the early CO2 main generation period is 0.5-0.7% and the burial depth is 2000-4000m;

[0056] The main natural gas generation period in this embodiment is the present period. If overheating occurs in the target area, it corresponds to the maximum paleotemperature period.

[0057] S103. Draw a dense sandstone paleo-structural geological map based on the key period, and delineate the scope of the structural transition superposition zone to obtain the target area;

[0058] In this embodiment, the tight sandstone target stratum is taken as the main object, that is, the regional tectonic evolution history and burial history are taken into consideration. The tight sandstone paleo-tectonic geological map includes the plane distribution map of the tight sandstone paleo-burial depth during the early CO2 main generation period and the plane distribution map of the tight sandstone paleo-burial depth during the main natural gas generation period.

[0059] In this embodiment, a low point range is constructed on the plane distribution map of the ancient burial depth of tight sandstone during the early main generation period of CO2, and a high point range is constructed on the plane distribution map of the ancient burial depth of tight sandstone during the main generation period of natural gas, and the overlapping area of ​​the above two ranges is delineated as the target area; wherein, the low point or high point is specifically: the distribution and depth of the tight sandstone relative to the main source rock are at a relative low point or high point.

[0060] S104. Classify the sandstone in the target area based on the reservoir characteristics and sedimentary facies of the tight sandstone to determine the distribution of tight sandstone gas sweet spots;

[0061] The reservoir characteristics of the tight sandstone in this embodiment include the lithology, mineral composition and depositional environment of the sand body itself;

[0062] The results of classifying the sandstones in this embodiment are as follows: the sandstones are classified into distributary channel sand bodies, distributary estuary sand bar sand bodies, distal sand bar sand bodies, breach fan sand bodies, beach bar sand bodies, delta sand bodies, and lake sand bodies in descending order of priority, among which the distributary channel sand bodies are the best sweet spots.

[0063] Example 2

[0064] This embodiment provides a method for predicting near-source tight sandstone gas sweet spots. The selected area is an area where uplift and erosion have occurred. The prediction method can efficiently and accurately predict the distribution of near-source tight sandstone gas sweet spots. The prediction method can be executed by a near-source tight sandstone gas sweet spot prediction device.

[0065] like Figure 1 As shown, the method provided in this embodiment includes:

[0066] S101. Restore the regional tectonic evolution history based on available geological parameters;

[0067] This example uses a comprehensive analysis of regional stratum thickness and the reflectance of vitrinite of terrigenous organic matter within the stratum to restore the regional tectonic evolution history.

[0068] For areas with relatively mature exploration and geological research, recognized research results can be directly used; for areas with low exploration levels, basin simulation software can be used to restore the tectonic evolution history of the study area based on the thickness of the strata revealed by drilling and the maturity of the organic matter therein.

[0069] S102. Determine key periods based on the regional tectonic evolution history, wherein the key periods include: an early CO2 main generation period and a natural gas main generation period;

[0070] In this embodiment, the early CO2 main generation period includes the low maturity stage of kerogen or source rock; further, the vitrinite reflectance Ro of the early CO2 main generation period is 0.5-0.7% and the burial depth is 2000-4000m;

[0071] The main generation period of natural gas in this embodiment is the maximum paleo-burial period of the source rock layer or tight sandstone.

[0072] S103. Draw a dense sandstone paleo-structural geological map based on the key period, and delineate the scope of the structural transition superposition zone to obtain the target area;

[0073] In this embodiment, the tight sandstone target stratum is taken as the main object, that is, the regional tectonic evolution history and burial history are taken into consideration. The tight sandstone paleo-tectonic geological map includes a planar distribution map of the ancient burial depth of the tight sandstone during the early main CO2 generation period, a planar distribution map of the ancient burial depth of the tight sandstone during the main natural gas generation period, and a planar distribution map of the ancient burial depth of the tight sandstone during the present period.

[0074] In this embodiment, a low point range is constructed on the plane distribution map of the ancient burial depth of tight sandstone in the early main generation period of CO2, a high point range is constructed on the plane distribution map of the ancient burial depth of tight sandstone in the main generation period of natural gas, and a high point range is constructed on the plane distribution map of the ancient burial depth of tight sandstone in the present period, and the overlapping area of ​​the above three ranges is delineated as the target area; wherein, the low point or high point is specifically: the distribution and depth of the tight sandstone relative to the main source rock are at a relative low point or high point.

[0075] S104. Classify the sandstone in the target area based on the reservoir characteristics and sedimentary facies of the tight sandstone to determine the distribution of tight sandstone gas sweet spots;

[0076] The reservoir characteristics of the tight sandstone in this embodiment include the lithology, mineral composition and depositional environment of the sand body itself;

[0077] The results of classifying the sandstones in this embodiment are as follows: the sandstones are classified into distributary channel sand bodies, distributary estuary sand bar sand bodies, distal sand bar sand bodies, breach fan sand bodies, beach bar sand bodies, delta sand bodies, and lake sand bodies in descending order of priority, among which the distributary channel sand bodies are the best sweet spots.

[0078] Example 3

[0079] This embodiment provides a prediction device for near-source tight sandstone gas sweet spots, such as Figure 2 As shown, the prediction device includes: a first recovery module 101, a first determination module 102, a first drawing module 103, and a second determination module 104, wherein:

[0080] The first restoration module 101 is used to restore the regional tectonic evolution history based on existing geological parameters;

[0081] The first determination module 102 is used to determine the key period according to the regional tectonic evolution history, wherein the key period includes: the early CO2 main generation period and the natural gas main generation period;

[0082] The first drawing module 103 is used to draw a dense sandstone paleo-structural geological map based on the key period, and to delineate the scope of the structural transition superposition area to obtain the target area;

[0083] The second determination module 104 is configured to classify the sandstone in the target area based on the reservoir characteristics and sedimentary facies of the tight sandstone, and determine the distribution of gas sweet spots in the tight sandstone.

[0084] In the first restoration module 101, the existing geological parameters include regional stratum thickness and vitrinite reflectance of terrigenous organic matter in the stratum.

[0085] In the first determination module 102, the early CO2 main generation period includes a low maturity stage of kerogen or source rock; the vitrinite reflectance Ro of the early CO2 main generation period is 0.5-0.7% and the burial depth is 2000-4000m;

[0086] The main natural gas generation period includes the following two situations:

[0087] For areas where no uplift or erosion has occurred, the main generation period of natural gas is the present period; or

[0088] In areas where uplift and erosion have occurred, the main generation period of natural gas is the maximum ancient burial period of the source rock layer or tight sandstone.

[0089] In the first drawing module 103, the drawing of the dense sandstone paleostructure geological map includes the following two cases:

[0090] For areas where no uplift and erosion has occurred, the dense sandstone paleo-tectonic geological map includes a planar distribution map of the paleo-burial depth of dense sandstone during the early main CO2 generation period and a planar distribution map of the paleo-burial depth of dense sandstone during the main natural gas generation period; or

[0091] For areas where uplift and erosion have occurred, the tight sandstone paleo-tectonic geological map includes a planar distribution map of the ancient burial depth of tight sandstone during the early main CO2 generation period, a planar distribution map of the ancient burial depth of tight sandstone during the main natural gas generation period, and a planar distribution map of the ancient burial depth of tight sandstone during the present period;

[0092] The scope of the structural conversion overlapping area is defined in the following two cases:

[0093] In areas where no uplift and erosion has occurred, the low point range is constructed on the plane distribution map of the ancient burial depth of tight sandstone during the early main generation period of CO2, and the high point range is constructed on the plane distribution map of the ancient burial depth of tight sandstone during the main generation period of natural gas. The overlapping area of ​​the above two ranges is delineated as the target area; or

[0094] In areas where uplift and erosion have occurred, a low point range is constructed on the plane distribution map of the ancient burial depth of tight sandstone during the early main CO2 generation period, a high point range is constructed on the plane distribution map of the ancient burial depth of tight sandstone during the main natural gas generation period, and a high point range is constructed on the plane distribution map of the ancient burial depth of tight sandstone in the present period. The overlapping area of ​​the above three ranges is delineated as the target area.

[0095] In the second determination module 104, the reservoir characteristics of the tight sandstone include the lithology, mineral composition and depositional environment of the sand body itself;

[0096] The results of the classification of the sandstone are as follows: in descending order of priority, they are divided into diversion channel sand body, diversion river mouth sand bar sand body, far sand bar sand body, breach fan sand body, beach bar sand body, delta sand body, and lake sand body; among them, the diversion channel sand body is the best sweet spot

[0097] The prediction device provided in this embodiment can execute the prediction method for near-source tight sandstone gas sweet spots provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0098] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for predicting near-source tight sandstone gas sweet spots, characterized by: The prediction method comprises: Restore the regional tectonic evolution history based on existing geological parameters; According to the regional tectonic evolution history, the key periods are determined, including the early CO2 main generation period and the natural gas main generation period; Based on the key periods, a dense sandstone paleo-tectonic geological map was drawn, and the scope of the structural conversion superposition zone was delineated to obtain the target area; The sandstones in the target area are graded based on the reservoir characteristics and sedimentary facies of the tight sandstones to determine the distribution of gas sweet spots in the tight sandstones.

2. The prediction method according to claim 1, characterized in that The existing geological parameters include regional stratum thickness and vitrinite reflectance of terrigenous organic matter in the stratum.

3. The prediction method according to claim 1, wherein: The early CO2 main generation period includes the low maturity stage of kerogen or source rock.

4. The prediction method according to claim 1, wherein: The vitrinite reflectance Ro during the early CO2 main generation period is 0.5-0.7%, and the burial depth is 2000-4000m.

5. The prediction method according to claim 1, wherein: The main natural gas generation period includes the following two situations: For areas where no uplift or erosion has occurred, the main generation period of natural gas is the present period; or In areas where uplift and erosion have occurred, the main generation period of natural gas is the maximum ancient burial period of the source rock layer or tight sandstone.

6. The prediction method according to claim 1, characterized in that The drawing of the dense sandstone paleo-structural geological map includes the following two situations: For areas where no uplift and erosion has occurred, the tight sandstone paleo-tectonic geological map shall include a planar distribution map of the paleo-burial depth of target strata during the early main generation period of CO2 and a planar distribution map of the paleo-burial depth of target strata during the main generation period of natural gas; or For areas where uplift and erosion have occurred, the dense sandstone paleo-structural geological map includes a planar distribution map of the paleo-burial depth of target strata during the early main CO2 generation period, a planar distribution map of the paleo-burial depth of target strata during the main natural gas generation period, and a planar distribution map of the paleo-burial depth of target strata in the present period.

7. The prediction method according to claim 1, wherein: The scope of the structural conversion overlapping area is defined in the following two cases: In areas where no uplift and erosion has occurred, a low point range is constructed on the horizontal distribution map of the ancient burial depth of the target strata during the early main CO2 generation period, and a high point range is constructed on the horizontal distribution map of the ancient burial depth of the target strata during the main natural gas generation period. The overlapping area of ​​the above two ranges is delineated as the target area; or In areas where uplift and erosion have occurred, a low point range is constructed on the plane distribution map of the ancient burial depth of the target strata during the early main CO2 generation period, a high point range is constructed on the plane distribution map of the ancient burial depth of the target strata during the main natural gas generation period, and a high point range is constructed on the plane distribution map of the ancient burial depth of the target strata in the present period. The overlapping area of ​​the above three ranges is delineated as the target area.

8. The prediction method according to claim 7, characterized in that The low point or high point specifically refers to the distribution and depth of the tight sandstone relative to the main source rock being at a relatively low point or high point.

9. The prediction method according to claim 1, characterized in that The reservoir characteristics of the tight sandstone include the lithology, mineral composition and sedimentary environment of the sand body itself.

10. The prediction method according to claim 1, wherein: The results of classifying the sandstones are as follows: in descending order of priority, they are distributary channel sand bodies, distributary estuary sand bar sand bodies, distal sand bar sand bodies, breach fan sand bodies, beach bar sand bodies, delta sand bodies, and lake sand bodies.

11. The prediction method according to claim 10, characterized in that: The diversion channel sand body is the best sweet spot.

12. A prediction device for near-source tight sandstone gas sweet spots, characterized by: The prediction device comprises: The first restoration module is used to restore the regional tectonic evolution history based on existing geological parameters; The first determination module is used to determine the key period according to the regional tectonic evolution history, and the key period includes: the early CO2 main generation period and the natural gas main generation period; The first drawing module is used to draw a dense sandstone paleo-structural geological map based on key periods, and to delineate the scope of the structural conversion superposition area to obtain the target area; The second determination module is used to classify the sandstone in the target area based on the reservoir characteristics and sedimentary facies of the tight sandstone and determine the distribution of gas sweet spots in the tight sandstone.

Images