Method for quantitatively predicting mudstone structure crack based on elastic-plastic mechanics

Abstract

The invention provides a method for quantitatively predicting mudstone structure fractures based on elastic-plastic mechanics, and relates to the technical field of oil exploration and development. The method for quantitatively predicting the mudstone tectonic fissures comprises the following steps: analyzing and counting the tectonic fissures of a single-well thick-layer mudstone section; carrying out rock mechanics experiment and mechanical parameter logging interpretation; calculating a brittleness index and a recovery paleomechanical parameter; establishing a mudstone yield-failure composite strength criterion; deducing a mudstone structure fracture mechanical parameter model; constructing a geologic model and recovering an ancient stress state; and simulating a three-dimensional ancient stress field and quantitatively predicting a crack. According to the technical scheme, the problem of establishment of the mudstone yield-fracture composite strength criterion under the brittleness index constraint is solved, and the method is suitable for crack quantitative prediction work of any mudstone-containing interlayer type clastic rock reservoir.

Description

technical field [0001] The present application relates to the technical field of petroleum exploration and development, in particular to a method for quantitatively predicting structural fractures in mudstone based on elastic-plastic mechanics. Background technique [0002] With the continuous development of oil and gas exploration and development and the continuous improvement of mining technology, complex fault block oil and gas reservoirs, lithologic oil and gas reservoirs, unconventional tight sandstone oil and gas reservoirs and fractured oil and gas reservoirs have attracted more and more attention; The basin is dominated by continental sedimentary strata. Frequent lake level changes have resulted in frequent vertical sandstone and mudstone changes. Under the action of multi-stage tectonic movements, a series of different mechanical properties have also developed in mudstone sections of different thicknesses. The cracks are mainly low-angle shear cracks, and the cracks...

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Problems solved by technology

[0003] At present, a large number of studies on fractures are mainly concentrated in the reservoir section, and relatively mature geological, geophysical and mechanical identification and prediction methods have gradually formed, but the research on mudstone and shale fractures is still at the stage of single well description and plane prediction , compared with sandstone reservoirs, mudstone shows different degrees of complex plastic mechanical behavior in the process of stress deformation due to the doping of limestone, silica, gypsum and other mineral components. The fracture prediction work of the

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