Numerical simulation method for acidification of double-mineral-component carbonate reservoir

Abstract

The invention relates to a numerical simulation method for acidification of a double-mineral-component carbonate reservoir, which belongs to the field of numerical simulation of oil and gas field reservoir transformation, and comprises the following steps: (1) simplifying mineral distribution in reservoir rock, dividing the pore volume in a unit into equivalent pore volumes of corresponding minerals according to the initial mineral content, and solving the equivalent porosity of each mineral; (2) establishing a double-scale continuous medium model for acidification of the double-mineral-component carbonate reservoir; (3) establishing a geometric model, dividing the geometric model into triangular grids by using a Delaunay method, and setting initial and boundary conditions on the geometric model; and (4) obtaining reservoir and acid liquid parameters, inputting the parameters into the model, and jointly solving a partial differential equation set through a finite element method to obtain an acidification numerical simulation result. According to the method, the complexity of carbonate rock mineral composition is considered, unification of acidification numerical models of carbonate rocks with different mineral components is achieved, and the method has great significance in carbonate rock reservoir acidification construction design and optimization.

Description

technical field [0001] The invention relates to a numerical simulation method for acidification of a dual-mineral component carbonate rock reservoir, and belongs to the technical field of numerical simulation of oil and gas field reservoir reformation. Background technique [0002] Carbonate rock oil and gas reserves account for nearly 60% of global reserves and are one of the important sources of oil and gas. Acidification is one of the commonly used methods for stimulation and stimulation of carbonate reservoirs. The principle of acidizing process is mainly to inject acid liquid under the condition of formation fracture pressure, increase reservoir permeability by dissolving carbonate cement and rock particles, reduce seepage resistance, and thus improve oil and gas recovery. The key to the success of acidizing construction is whether the wormhole corrosion pattern is formed. However, due to technical limitations, accurate information on the subsurface acid corrosion patt...

AI Technical Summary

Problems solved by technology

The difference of different acid-rock reaction rates affects the acidification simulation results mainly in two aspects: on the one hand, during the acid-rock reaction process, the acid liquid dissolves the rock matrix, and the porosity gradually increases, but due to the reaction rate of different minerals The range and rate of porosity increase are also different, and different porosity distributions will lead to differences in corrosion forms; on the other hand, the formation of wormhole acid corrosion forms needs to ensure that the mass transfer rate and reaction rate are close The injection rate under this condition is the optimal injection rate, and the reaction rates of different minerals vary greatly. Regardless of the difference in mineral composition and distribution, the mass transfer rate may change with the change of the reaction rate, and ultimately affect the optimal injection rate. judge

[0004] None of the current acidification models can accurately predict the acid erosion form of carbonate rock reservoir acidification with different mineral compositions. Therefore, how to comprehensively consider the complexity of carbonate rock mineral composition and simplifies and assumes the pores and pores, and proposes a numerical model and numerical simulation method suitable for acidification of carbonate rock reservoirs with different mineral compositions, so as to realize the unification of numerical models of carbonate rock acidification with different mineral compositions. Layer acidification construction design and optimization are of great significance

Images