Quantitative discrimination method for fault instability in pressure driving process

Abstract

The invention provides a quantitative discrimination method for fault instability in a pressure driving process, which comprises the following steps of: 1, depicting a fault zone structure, and establishing an oil reservoir finite element geologic model; 2, calculating the three-dimensional distribution of the current crustal stress field based on an elastic-plastic finite element simulation platform; step 3, based on a fluid-solid coupling principle, determining a fluid disturbance dominant channel, setting water injection pressure and increment, and calculating to obtain dynamic crustal stress field change data; 4, based on the critical water injection pressure calculation model causing fault instability, the fault instability inducing probability in the pressure driving process is obtained. The method solves the problem of effectively depicting the fault zone structure by integrating rock core, logging and seismic data and the problem of fault instability risk prediction under the coupling of a dynamic stress field and a tectonic mechanics principle, and is suitable for fault geologic modeling of any low-permeability reservoir and pressure driving recovery efficiency improvement work. A reliable basis is provided for greatly improving the injection capacity of the low-permeability reservoir and improving the development effect, and the development risk and cost are reduced.

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