A method for multi-scale evaluating the capping ability of block transport and deposition

Abstract

The present invention discloses a method for multi-scale evaluation of the capping ability of mass transport deposits. The method is as follows: identifying mass transport deposits; judging the continental margin type, depositional system tract, depositional environment and submarine landslide source of the mass transport deposits; finely depicting the mass transport deposit system in seismic profiles, distinguishing its strain domain, counting its thickness, identifying the number of fluid escape structures and the number of floating blocks; establishing an evaluation matrix diagram, plotting the evaluations of each parameter on the above diagram; listing an evaluation table based on the plotting results, assigning scores to each parameter, and calculating the average scores X 盆地 and X 地震 ; based on the sub-item evaluation results, calculating the capping ability score by weighted calculation to determine the capping ability of the mass transport deposits. Starting from seismic profiles, the present invention comprehensively analyzes the capping ability of mass transport deposits with multi-scale parameters, and finally realizes the semi-quantitative evaluation of the capping ability of mass transport deposits to meet the requirements of oil and gas exploration and development at different stages.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum geology, and particularly relates to a method for multi-scale evaluation of the sealing ability of mass transport deposits. Background Art

[0002] As a common gravity flow deposit, the mass transport deposit system is widely developed in deep-water basins. With the gradual exploration of oil and gas towards the deep sea, the mass transport deposit system has gradually become a key component in the oil and gas system of deep-water basins. Previous studies and exploration practices in deep-water basins in China have confirmed that cases of the mass transport deposit system acting as both a cap rock and a reservoir in the oil and gas system have been reported, which mainly depends on the sealing ability of the mass transport deposit system. There are differences in the types and sedimentary environments of different mass transport deposit systems, and there is also strong heterogeneity within the same mass transport deposit system. The existing technology mainly evaluates the sealing ability of the mass transport deposit system through physical property tests (such as porosity, permeability, etc.). However, it is difficult to obtain sediment samples in deep-water basins, and there is a lack of relevant physical property test data, which increases the difficulty of evaluating the sealing ability of the mass transport deposit system. At the same time, dozens of mass transport deposit systems can be developed in a deep-water basin. It is difficult and expensive to sample and test them one by one. Therefore, there is an urgent need for a simple, effective, highly operable and non-complex test method for evaluating the sealing ability of the mass transport deposit system. Summary of the Invention

[0003] The purpose of the present invention is to propose a method for multi-scale evaluation of the sealing ability of mass transport deposits in view of the above deficiencies of the existing technology.

[0004] A method for multi-scale evaluation of the sealing ability of mass transport deposits of the present invention includes the following steps:

[0005] S1, identifying mass transport deposits, and identifying mass transport deposits in seismic data according to the seismic reflection characteristics of the mass transport deposit system;

[0006] S2, basin-scale qualitative evaluation, judging the continental margin type, sedimentary system domain, sedimentary environment and submarine landslide source of the mass transport deposits through investigation and regional geological overview;

[0007] S3, seismic-scale semi-quantitative evaluation, finely depicting the mass transport deposit system in the seismic profile, distinguishing its strain domain, counting its thickness, identifying the number of fluid escape structures and the number of floating blocks;

[0008] S4. Establish an evaluation matrix diagram for the block transport and deposition capping ability. Plot the evaluations of each parameter of block transport and deposition in steps S2 and S3 on the evaluation matrix diagram for the block transport and deposition capping ability. Based on the plotted results, list a sub-evaluation table for the block transport and deposition capping ability, assign scores to each parameter, and calculate the average scores X 盆地 and X 地震 ;

[0009] S5. Based on the weighted calculation of the sub-evaluation results, calculate the score of the block transport and deposition capping ability. The score X 总 =A*X 盆地 +B*X 地震 , where A + B = 1 and B > A; Determine the block transport and deposition capping ability based on the magnitude of X 总 .

[0010] Furthermore, for thickness statistics, first, the two-way reflection time difference between the top and bottom interfaces needs to be statistically analyzed from seismic data, and the thickness of the block transport and deposition system is calculated using the formula:

[0011] H = dT×V

[0012] where the thickness H (unit: meter), dT is the two-way reflection time difference between the top and bottom interfaces, and V is the seismic wave velocity.

[0013] Furthermore, the scoring principle for seismic scale parameters is as follows: According to its stress state, the strain domain can be divided into three strain domains, namely the head, body, and toe. The score for the head is -1, the score for the body is 0, and the score for the toe is 1; When the thickness H is less than 15m, the score is -1; when the thickness H is equal to 15m, the score is 0; when the thickness H is greater than 15m and less than 80m, the score is 0.5; when the thickness H is not less than 80m, the score is 1; When the number of fluid escape structures is greater than 3, the score is -1; when it is equal to 3, the score is 0; when it is less than 3, the score is 1; When the number of floating blocks is greater than 33, the score is -1; when it is equal to 3, the score is 0; when it is less than 3, the score is 1.

[0014] Furthermore, the scoring principle for basin scale parameters is as follows: The continental margin types are divided into passive continental margin basins and active continental margin basins. The score for passive continental margin basins is 1, and the score for active continental margin basins is -1; The sedimentary system domains are divided into lowstand system domain, highstand system domain, and transgressive system domain. The score for the lowstand system domain is -1, the score for the highstand system domain is 0, and the score for the transgressive system domain is 1; The sedimentary environments are divided into slope sedimentary environment and abyssal plain sedimentary environment. The score for the slope sedimentary environment is -1, and the score for the abyssal plain sedimentary environment is 1; The sources of submarine landslides are divided into shelf source, slope source, and deep-sea local uplift source. The score for the shelf source is -0.5, the score for the slope source is -1, and the score for the deep-sea local uplift source is 1.

[0015] Further, A = 1 / 3 and B = 2 / 3.

[0016] Further, in step S5, if the value of X 总 is between 0 and 0.5, the capping ability is medium. If the value of X 总 is between 0.5 and 1, the capping ability is good. If the value of X 总 is less than 0, the capping ability is poor.

[0017] The present invention provides a simple and easy-to-implement method for evaluating the capping ability of mass transport deposits with low data requirements. Starting from seismic profiles, multi-scale parameters are comprehensively analyzed to evaluate the capping ability of mass transport deposits, and finally a semi-quantitative evaluation of the capping ability of mass transport deposits is achieved to meet the needs of oil and gas exploration and development at different stages.

[0018] The present invention has the following advantages: ① Comprehensive parameters and pertinence. The present invention comprehensively evaluates the capping ability of the mass transport deposit system from macro to micro, integrates and formulates various parameter standards for the capping ability of the mass transport deposit system; ② Low data requirements and strong operability. The present invention evaluates the capping ability of the mass transport deposit system based on seismic data and drilling and logging data. The key areas for oil and gas exploration in China's sea areas have basically achieved full coverage of seismic data, such as the Qiongdongnan Basin and the Pearl River Mouth Basin. Therefore, the present invention has a wide application range and strong universality in marine oil and gas exploration; ③ It meets the evaluation requirements of the capping ability of mass transport deposit systems at multiple stages and multiple scales. Among them, basin-scale and seismic-scale evaluations correspond to 2D seismic data and 3D seismic data respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the seismic profile of the mass transport deposit system in Example 1;

[0020] Figure 2 It is the evaluation matrix diagram of the capping ability of the mass transport deposit system;

[0021] Figure 3 It is a schematic diagram of the points plotted for the evaluation of each parameter of the mass transport deposit in Example 1 on the evaluation matrix diagram of the capping ability of the mass transport deposit. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following are specific embodiments of the present invention in combination with the drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0023] (1) Seismic identification and fine interpretation of the mass transport deposit system

[0024] The physical properties of the mass transport deposition system are quite different from those of the in-situ seafloor deposits, so its seismic reflection characteristics are relatively obvious, usually manifested as strong reflection top and bottom interfaces with good continuity and internal reflection structures with poor continuity or blank reflections. Identify and interpret the mass transport deposition system in seismic data based on the above seismic reflection characteristics.

[0025] (2) Basin-scale qualitative evaluation

[0026] The main basin-scale qualitative evaluation parameters related to the sealing ability of the mass transport deposition system are as follows: ① continental margin type; ② depositional system tract; ③ depositional environment; ④ source of submarine landslides. Now, further explanations of the evaluation criteria for the above four parameters are given:

[0027] ① Continental margin type: The transport distance of the mass transport deposition system developed in passive continental margin basins (about 1000 km) is usually one order of magnitude smaller than that in active continental margins (about 100 km). At the same time, the mass transport deposition system in active continental margins has higher shear strength due to active seismic activities and is more likely to undergo brittle fracture to form faults, thus reducing its sealing ability. Therefore, the mass transport deposition system in passive continental margin basins has higher sealing ability;

[0028] ② Depositional system tract: Sequence stratigraphy indicates that the sediment grain size is strongly correlated with the progradation, aggradation, and retrogradation processes of the coastline, and the sealing ability of mudstone varies systematically in the depositional system tract. The mass transport deposition system developed in the lowstand system tract has a higher sandy content. The sandy content of the mass transport deposition developed in the highstand system tract is usually between that of the transgressive system tract and the lowstand system tract, with medium sealing ability, while the mudstone in the transgressive system tract usually has good sealing ability;

[0029] ③ Depositional environment: The mass transport deposition system develops in various depositional environments in deep-water basins, such as the continental slope, deep-sea plain, etc. Generally, from the continental slope to the deep-sea plain, the sandy content of the mass transport deposition system gradually decreases, and the sealing ability gradually increases;

[0030] ④ Source of submarine landslides: The sediments of the mass transport deposition system usually have two sources. One is the shelf-slope source, which usually has a higher sandy content, and the other is the deep-sea local uplift, whose sediment source is deep-sea mud deposition. In contrast, the mass transport deposition system sourced from deep-sea local uplifts is more likely to form an effective seal.

[0031] (3) Seismic-scale semi-quantitative evaluation

[0032] The main medium-scale semi-quantitative evaluation parameters related to the sealing ability of the mass transport deposition system are as follows: ① strain domain; ② thickness; ③ number of fluid escape structures; ④ number of floating blocks. Now, further explanations of the evaluation criteria for the above four parameters are given:

[0033] ①Strain domain: According to its stress state, the mass transport deposit system can be divided into three strain domains, namely the head, the body, and the toe. Normal faults usually develop in the head, which will significantly damage the sealing ability of the mass transport deposit system. Reverse faults and compression ridges usually develop in the toe. The sediments are compressed, with higher density, lower porosity and permeability, and usually have good sealing ability. The body is between the head and the toe, in the transitional section of the stress state, and some faults develop, but the density and throw are smaller than those in the head. Therefore, it is considered that the sealing ability of the mass transport deposit system is toe > body > head.

[0034] ②Thickness: The possibility of the existence of penetrating faults and fractures in the thick mass transport deposit system is lower than that in the thin mass transport deposit system, that is, the sealing ability is stronger. When the mass transport deposit system is thin to a certain extent, it will be difficult to block the migration of fluids, that is, there is a lower limit of thickness for the mass transport deposit system as a caprock. This lower limit is about 15 m, and when the thickness of the mass transport deposit system reaches more than 80 m, its sealing ability will be greatly enhanced.

[0035] ③Number of fluid escape structures: Fluid escape structures refer to the structures formed by the piercing / permeation of fluids into the caprock after the fluids accumulate to reach the sealing limit of the caprock. Common fluid escape structures include pockmarks, gas chimneys, and conduit structures. Fluid escape structures directly indicate the interaction between the submarine mass transport deposit system and fluids, and are important indicators for evaluating the sealing ability of the mass transport deposit system. The development of fluid escape structures is now divided into none, few (0 - 3), and many (more than 3).

[0036] ④Number of floating blocks: Floating blocks refer to the original sedimentary blocks without deformation or weak deformation inside the mass transport deposit system. There is discontinuity between the floating blocks and the surrounding sediments, and their contact surface is a preferential fluid migration channel relative to the homogeneous muddy sediment. Therefore, floating blocks may reduce the sealing ability of the mass transport deposit system. The development of floating blocks is now divided into none, few (0 - 3), and many (more than 3).

[0037] (4)Establish an evaluation matrix for the sealing ability of the mass transport deposit system

[0038] Integrate the above various parameters into the same matrix and conduct classification evaluation according to the scale of the parameters. We have formulated evaluation criteria for all the above parameters and assigned scores of -1, 0, and 1 according to this criterion, corresponding to poor, medium, and excellent sealing abilities respectively. If further subdivision is required, two scores of -0.5 and 0.5 are introduced. For example, in the mass transport deposit type, the continental shelf and the continental slope can be distinguished. The continental slope is assigned a score of -0.5, while the worse continental shelf is assigned a score of -1.

[0039] (5)Comprehensively evaluate the sealing ability of the mass transport deposit

[0040] After each parameter is scored according to the standard, the average scores of the parameters at the basin scale and the seismic scale need to be calculated separately, and the final score is calculated by weighting. The weights of the basin-scale and seismic-scale parameters need to be determined according to the actual data situation and the actual usage scenario. When evaluating the overall sealing ability of the mass transport deposition system, the weight of the basin-scale parameters needs to be increased. When evaluating the sealing ability of a certain part of the mass transport deposition system, the weight of the seismic-scale parameters needs to be increased.

[0041] A method for multi-scale evaluation of the sealing ability of mass transport deposition based on the above-mentioned invention of the present invention includes the following steps:

[0042] S1. Identify the mass transport deposition, and identify the mass transport deposition in the seismic data according to the seismic reflection characteristics of the mass transport deposition system;

[0043] S2. Qualitative evaluation at the basin scale, judge the continental margin type, sedimentary system domain, sedimentary environment and submarine landslide source of the mass transport deposition through investigation and regional geological overview;

[0044] S3. Semi-quantitative evaluation at the seismic scale, finely depict the mass transport deposition system in the seismic profile, distinguish its strain domain, count its thickness, identify the number of fluid escape structures and the number of floating blocks;

[0045] S4. Establish an evaluation matrix diagram for the sealing ability of mass transport deposition, and project the evaluations of each parameter of the mass transport deposition in steps S2 and S3 into the evaluation matrix diagram for the sealing ability of mass transport deposition; based on the projection results, list the sub-item evaluation table for the sealing ability of mass transport deposition, score each parameter, and calculate the average scores X 盆地 and X 地震 ;

[0046] S5. Calculate the sealing ability score of the mass transport deposition by weighting based on the sub-item evaluation results. The sealing ability score X 总 =A*X 盆地 +B*X 地震 , A + B = 1, B > A; judge the sealing ability of the mass transport deposition through the size of X 总 .

[0047] For thickness statistics, first, the difference in two-way reflection time between the top and bottom interfaces needs to be statistically calculated in the seismic data, and the thickness of the mass transport deposition system is calculated using the formula:

[0048] H = dT×V

[0049] where the thickness H (unit: meter), dT is the difference in two-way reflection time between the top and bottom interfaces, and V is the seismic wave velocity.

[0050] The scoring principle for seismic scale parameters is as follows: According to its stress state, the strain domain can be divided into three strain domains, namely the head, the body, and the toe. The head is scored -1, the body is scored 0, and the toe is scored 1; when the thickness H is less than 15m, it is scored -1, when the thickness H is equal to 15m, it is scored 0, when the thickness H is greater than 15m and less than 80m, it is scored 0.5, and when the thickness H is not less than 80m, it is scored 1; when the number of fluid escape structures is greater than 3, it is scored -1, when it is equal to 3, it is scored 0, and when it is less than 3, it is scored 1; when the number of floating blocks is greater than 33, it is scored -1, when it is equal to 3, it is scored 0, and when it is less than 3, it is scored 1.

[0051] The scoring principle for basin scale parameters is as follows: The types of continental margins are divided into passive continental margin basins and active continental margin basins. Passive continental margin basins are scored 1, and active continental margin basins are scored -1; sedimentary system tracts are divided into lowstand system tracts, highstand system tracts, and transgressive system tracts. Lowstand system tracts are scored -1, highstand system tracts are scored 0, and transgressive system tracts are scored 1; sedimentary environments are divided into slope sedimentary environments and abyssal plain sedimentary environments. Slope sedimentary environments are scored -1, and abyssal plain sedimentary environments are scored 1; the sources of submarine landslides are divided into shelf sources, slope sources, and abyssal local uplift sources. Shelf sources are scored -0.5, slope sources are scored -1, and abyssal local uplift sources are scored 1.

[0052] The evaluation matrix diagram of the block - transport deposit capping ability established using the above - mentioned scoring principle is as Figure 2 shown.

[0053] A = 1 / 3, B = 2 / 3. In step S5, if the value of X 总 is between 0 and 0.5, the capping ability is medium. If the value of X 总 is between 0.5 and 1, the capping ability is good. If the value of X 总 is less than 0, the capping ability is poor.

[0054] The following is a specific evaluation of block - transport deposits

[0055] Example 1

[0056] Step 101: Identify block - transport deposits in seismic data according to the seismic reflection characteristics of the block - transport deposit system.

[0057] Referring to Figure 1 , block - transport deposit systems A, B, and C can be clearly identified from the seismic profile according to the seismic reflection characteristics of "the top - bottom interfaces of strong reflections with good continuity and the internal reflection structures of poor - continuity or blank reflections".

[0058] Step 102, Basin-scale qualitative evaluation. Through investigations and regional geological profiles, it is known that the mass transport deposit systems A, B, and C are located in the Qiongdongnan Basin in the South China Sea, which is a passive continental margin basin. The mass transport deposit systems A, B, and C were all deposited in the Ledong Formation, belonging to the lowstand systems tract deposits. The sedimentary environments of the mass transport deposit systems A, B, and C are all deep-sea plains. The provenance of the mass transport deposit A is from the shelf area, the provenance of the mass transport deposit B is from the slope area, and the provenance of the mass transport deposit C is from the deep-water uplift area.

[0059] Step 103, Seismic-scale semi-quantitative evaluation. In the seismic profile, finely depict the mass transport deposit system, count its thickness, identify its strain domain, and recognize fluid escape structures and floating blocks.

[0060] For thickness statistics, first count the two-way traveltime difference between the top and bottom interfaces in the seismic data, and use the formula to calculate the thickness of the mass transport deposit system.

[0061] H = dT × V

[0062] Where the thickness H (unit: meter), dT is the two-way traveltime difference between the top and bottom interfaces, and V is the seismic wave velocity. In the study area near the seabed, the seismic wave velocity is usually taken as 1700 m / s. The two-way traveltime difference between the top and bottom interfaces of the mass transport deposit system A is counted as 0.09 s, and the thickness is 153 m; the two-way traveltime difference between the top and bottom interfaces of the mass transport deposit system B is counted as 0.05 s, and the thickness is 85 m; the two-way traveltime difference between the top and bottom interfaces of the mass transport deposit system C is counted as 0.03 s, and the thickness is 51 m.

[0063] The strain domain is mainly determined based on the relative position of the evaluation point and the provenance and the fault properties, etc. First, it is necessary to depict the scope of the mass transport deposit system on the plane. The provenances of the mass transport deposits A and B are from the northern slope area, and the provenance of the mass transport deposit C is from the deep-water uplift area. Determine the strain domain according to the relative position of the target point and the provenance direction, that is, the target point located at the proximal end of the provenance is the head, the target point located at the distal end of the provenance is the toe, and the middle part is the body. As Figure 1 shown, the point Well1 is located in the middle part of the mass transport deposit A, belonging to the body, and the point Well 2 is located at the distal ends of the mass transport deposits B and C, belonging to the toe.

[0064] Fluid escape structures are mainly identified in the seismic profile, which are manifested as vertically stacked in-phase axis dislocations and blank reflections. As Figure 1 shown, 1 fluid escape structure is found in the mass transport deposit B, 5 fluid escape structures are found in the mass transport deposit C, and no fluid escape structure is found in the mass transport deposit A.

[0065] Floating blocks are mainly identified in seismic profiles, manifested as relatively continuous enhanced reflections in mass transport deposits. For example Figure 1 As shown, 3 floating blocks were found in mass transport deposit B, 1 floating block was found in mass transport deposit C, and no floating blocks were found in mass transport deposit A

[0066] Step 104, establish an evaluation matrix diagram for the capping ability of mass transport deposits ( Figure 2 ). Based on the evaluation of each parameter of the three sets of mass transport deposits above, plot points in the evaluation matrix of the capping ability of mass transport deposits ( Figure 3 ). Based on the plot point results, list the sub-item evaluation table of the capping ability of mass transport deposits, and calculate the average scores at the basin scale and seismic scale respectively (Table 1).

[0067] Step 105, based on the sub-item evaluation results, calculate the capping ability score of mass transport deposits by weighting. The seismic scale can directly reflect the capping ability of mass transport deposits, so its weight needs to be increased during the evaluation process. In this embodiment, the weight of the basin scale: seismic scale = 1:2 is adopted, that is, the comprehensive score X of the capping ability of mass transport deposits 总 = 1 / 3 * X 盆地 + 2 / 3 * X 地震 . Using the above method, the capping ability scores of mass transport deposits A, B, and C are calculated to be 0.54166, 0.5, and 0.417 respectively (Table 2). Generally speaking, the capping abilities of mass transport deposits A and B are better, while that of mass transport deposit C is medium

[0068] The difference in porosity from the surrounding rock is mainly obtained through neutron porosity logging. The average neutron porosity of mass transport deposit A in Well 1 is 52%, and the average neutron porosity of the surrounding rock (taking the porosity of three meters above and below mass transport deposit A and taking the average value) is 65%. The difference in porosity T between mass transport deposit A and the surrounding rock A = 65% - 52% = 13%, while the average neutron porosity of mass transport deposit B in Well 2 is 61%, the average neutron porosity of the surrounding rock is 68%, and the difference in porosity T between mass transport deposit B and the surrounding rock B = 68% - 61% = 7%. The average neutron porosity of mass transport deposit C is 63%, the average neutron porosity of the surrounding rock is 66%, and the difference in porosity T between mass transport deposit C and the surrounding rock C = 66% - 63% = 3%. The measured data shows that the differences in porosity between mass transport deposits A and B and the surrounding rock are relatively large, and the porosity of mass transport deposit C is relatively close to that of the surrounding rock. The capping ability A > B > C, which is coupled with the prediction results, verifying the effectiveness and accuracy of this method

[0069] Table 1 Sub-item evaluation table of the capping ability of mass transport deposits

[0070] Continental margin type System tract Depositional environment Mass transport deposit type Basin-scale mean Strain domain Thickness Fluid escape structure Floating block Seismic-scale mean A 1 -1 1 -0.5 0.125 0 1 1 1 0.75 B 1 -1 1 -1 0 1 1 1 0 0.75 C 1 -1 1 1 0.5 1 0．5 -1 1 0.375

[0071] Table 2 Comprehensive evaluation table of the block handling, deposition and capping ability

[0072]

[0073] Where not otherwise involved, the prior art shall apply.

[0074] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of the present invention. Those skilled in the technical field to which the present invention pertains can make various modifications or supplements to the specific embodiments described or substitute them in a similar manner, but will not deviate from the direction of the present invention or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc. made to the above embodiments based on the technical essence of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for multi-scale evaluating the capping ability of block transport and deposition, characterized in that: It includes the following steps: S1. Identify mass transport deposits. Identify mass transport deposits in seismic data according to the seismic reflection characteristics of the mass transport deposit system; S2. Basin-scale qualitative evaluation. Judge the continental margin type, depositional system tract, depositional environment and submarine landslide source of the mass transport deposits through investigation and regional geological overview; S3. Seismic-scale semi-quantitative evaluation. Fine-scale the mass transport deposit system in the seismic profile, distinguish its strain domain, count its thickness, identify the number of fluid escape structures and the number of floating blocks; S4. Establish an evaluation matrix diagram for the sealing ability of mass transport deposits. Plot the evaluations of each parameter of the mass transport deposits in steps S2 and S3 on the evaluation matrix diagram for the sealing ability of mass transport deposits; List a sub-item evaluation form for the block transportation, deposition, and capping capabilities based on the throwing point results, assign scores to each parameter, and calculate the average scores X 盆地 and X 地震 ; S5. Calculate the score of the block transport and deposition capping ability based on the weighted sub-evaluation results. The score of the block transport and deposition capping ability ; Determine the block transport and deposition capping ability by the size of X 总 .

2. The method for multi-scale evaluating the ability of block transportation, deposition and capping according to claim 1, wherein: For thickness statistics, first count the two-way reflection time difference between the top and bottom interfaces in the seismic data, and calculate the thickness of the mass transport deposit system using the formula: where the thickness H is in meters, is the difference in two-way reflection time between the top and bottom interfaces, and V is the seismic wave velocity.

3. The method for evaluating the block transportation, deposition and capping ability at multiple scales according to claim 2, characterized in that: The scoring principle for seismic-scale parameters is as follows: The strain domain can be divided into three strain domains according to its stress state, namely the head, body and toe. The head is scored -1, the body is scored 0, and the toe is scored 1; When the thickness H is less than 15m, it is scored -1; when the thickness H is equal to 15m, it is scored 0; when the thickness H is greater than 15m and less than 80m, it is scored 0.5; when the thickness H is not less than 80m, it is scored 1; When the number of fluid escape structures is greater than 3, it is scored -1; when it is equal to 3, it is scored 0; when it is less than 3, it is scored 1; When the number of floating blocks is greater than 33, it is scored -1; when it is equal to 3, it is scored 0; when it is less than 3, it is scored 1.

4. The method for multi-scale evaluation of the block transportation, deposition and capping ability according to claim 3, characterized in that: The scoring principle for basin-scale parameters is as follows: The continental margin type is divided into passive continental margin basins and active continental margin basins. Passive continental margin basins are scored 1, and active continental margin basins are scored -1; The depositional system tract is divided into lowstand system tract, highstand system tract and transgressive system tract. The lowstand system tract is scored -1, the highstand system tract is scored 0, and the transgressive system tract is scored 1; The depositional environment is divided into slope depositional environment and abyssal plain depositional environment. The slope depositional environment is scored -1, and the abyssal plain depositional environment is scored 1; The submarine landslide source is divided into shelf source, slope source and deep-sea local uplift source. The shelf source is scored -0.5, the slope source is scored -1, and the deep-sea local uplift source is scored 1.

5. The method for evaluating the block transportation, deposition and capping ability at multiple scales according to claim 4, wherein: A = 1 / 3, B = 2 / 3.

6. The method for multi-scale evaluating the block transportation, deposition and capping ability according to claim 5, wherein: In step S5, if X 总 has a value between 0 and 0.5, the capping ability is medium. If X 总 has a value between 0.5 and 1, the capping ability is good. If X 总 has a value less than 0, the capping ability is poor.

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