A method for recovering the brittle-plastic evolution history of oil and gas cap rocks

Abstract

The invention provides a method for restoring brittleness and plasticity evolution history of petroleum and natural gas cap rocks, and belongs to the field of oil-gas exploration. According to the method, temperature and stress characteristics of the cap rocks in a specific geological historical period and the resulting changes of plasticity coefficients of the cap rocks are restored, and further, dynamic evolution conditions of brittleness and plasticity coefficients of the cap rocks in different geological historical periods are restored so as to evaluate sealing performance of the cap rocks. By the method, a cap rock effectiveness evaluation system can be formed by combination of mature technology systems in some specific fields, can be used for evaluating effectiveness of the cap rocks in a certain specific geological historical period, and can be combined with structural evolution of basins and stratal up-down history to dynamically evaluate the change characteristic of sealing capability of the cap rocks in the certain geological historical period.

Description

technical field [0001] The invention belongs to the field of oil and gas exploration, in particular to a method for restoring the brittle-plastic evolution history of oil and natural gas cap rocks. Background technique [0002] At present, the existing cap rock sealability evaluation method takes breakthrough pressure as the core and various static rock mechanics parameters as the main body, which has certain limitations. More and more exploration practices have proved that under stratigraphic conditions, the brittle-plastic characteristics of the caprock and the risk of micro-fractures are the key issues in evaluating the oil and gas preservation conditions in multi-cycle reformed basins. The main geological factors affecting the brittle-plastic evolution of the caprock include: (1) the rock mechanical properties of the caprock itself; (2) the in-situ stress field in the geological environment of the caprock; (3) the geological environment of the caprock characteristics of...

AI Technical Summary

Problems solved by technology

However, at present, these technologies only serve the single field of rock mechanical property evaluation, in-situ stress field restoration, and structural evolution, and cannot be used as an evaluation index for the sealing performance of specific caprock rock tomography in the geological evolution history process.

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