Seam-following cave-finding acid fracturing numerical simulation method and simulation system

Abstract

The invention discloses a fracture-following cavern-finding acid fracturing numerical simulation method, which comprises the following steps: establishing a stress-flow-acid rock reaction coupling mathematical model: establishing a stress-flow-acid rock reaction coupling control equation, and setting initial conditions and boundary conditions; adopting a maximum strain energy release rate criterion to judge crack propagation; combining the control equation and the boundary condition by adopting a weighted margin method to obtain an equivalent integral weak form of the control equation; discretizing the control equation by adopting an extended finite element method to obtain an extended finite element discrete equation; establishing a physical model containing natural fractures and karst caves; and calculating the physical model based on the extended finite element discrete equation. According to the method, a set of crack hole type carbonate reservoir acid etching crack propagation model comprising a stress module, a flow module and an acid rock reaction module is established, a control equation is discretized by adopting an expansion finite element method, crack propagation is judged by utilizing a maximum strain energy release rate criterion, and an acid etching crack propagation path is researched.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development, in particular to a numerical simulation method and a simulation system for finding cavities through fractures. Background technique [0002] Carbonate rock oil and gas reservoirs contribute more than half of the global oil and gas production, and acid fracturing is an important acid for the efficient and economic development of carbonate rocks. Two indicators for evaluating the effect of acid fracturing include the effective distance of acid solution, acid erosion Fracture conductivity. On the one hand, the effective etching of the rock by the acid solution can increase the fracture width, thereby improving the fracture conductivity; In addition, the propagation behavior of acid-etched fractures is greatly affected by geological discontinuities such as natural fractures and karst caves. Therefore, the morphology of acid-etched fractures is quite different from that in homog...

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Problems solved by technology

[0004] The existing acid fracturing numerical simulation methods are generally used for numerical simulation of conventional homogeneous reservoirs, without considering the establishment of natural fractures and caves, and are not suitable for numerical simulation of fractured-vuggy reservoirs. Therefore, it is necessary to establish a Numerical Simulation Method of Cave Reservoir

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