Glutenite hydrofracture simulation method based on discrete element

Abstract

The invention relates to a glutinite hydrofracture simulation method based on a discrete element. The method comprises the following steps of: S1, constructing a wall and a well bore, generating particles according to a size grading curve, and performing initial balance calculation, S2, dividing the particles into a matrix and gravel by a cutting method, endowing the matrix and the gravel with different cementing parameters, S3, adding a seepage field and endowing a corresponding flow parameter, S4, applying confining pressure on the external wall based on a servo system, setting a fluid injection speed, S5, monitoring cementing states of the particles in real time, and judging whether micro cracks are generated according to the cementing states, and S6, continuing simulation till penetration of hydraulic cracks occurs. The glutinite hydrofracture simulation method based on the discrete element can characterize crack initiation and expansion mechanisms of the hydraulic cracks preciselyfrom a microscale, and accurately capture a macro distribution morphology of the hydraulic cracks, so that the understanding of a field engineer on an expansion rule of the hydraulic cracks of a glutinite reservoir is enhanced; and a fracture design is improved.

Description

technical field [0001] The invention relates to the technical field of hydraulic fracturing of glutenite oil and gas reservoirs, in particular to a simulation method for hydraulic fracturing of glutenite based on discrete elements. Background technique [0002] Glutenite widely exists in tight oil and gas reservoirs, but due to its high burial depth, glutenite usually has the characteristics of low permeability and low porosity, so hydraulic fracturing technology is required for stimulation operations to form fractures with high conductivity underground. Enhance the ability of oil and gas to flow into the well, and then increase the productivity of oil and gas wells to achieve economical and efficient production. Clarifying the fracture initiation mechanism and the final distribution of fractures in glutenite hydraulic fracturing is the prerequisite for the implementation of hydraulic fracturing technology, and has important guiding significance for fracturing design. Howev...

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Problems solved by technology

However, due to the high degree of geometric heterogeneity and the induced stress heterogeneity and strength heterogeneity, the fracture initiation mechanism and fracture distribution of glutenite hydraulic fracturing are more complicated, and due to the existence of gravel, the hydraulic fracture Frequent interaction with gravel further affects its expansion

Although true triaxial experiments and numerical simulation techniques have explored the hydraulic fracture propagation law of glutenite from different angles, it is difficult to accurately characterize the rock mechanical behavior and the flow-stress-displacement coupling problems involved in the hydraulic fracturing process.

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