Lattice Boltzmann Study Of Acid-Rock Heterogeneous Flow Reactive In Porous Media

Acidizing is the main technology for production and stimulation of oil and gas wells,as well as increasing injection of injection wells.Because of the huge contribution to the development of oil and gas fields,this technology is highly valued and widely used at home and abroad.The sandstone reservoir has many mineral components and complex chemical compositions,which leads to the complex mechanism of acid-rock heterogeneous reactive in porous media.Meanwhile,precipitates in the acid-rock reaction may cause secondary damage to the reservoir.Blind acidification construction design will greatly reduce the success rate of sandstone acidification,which in turn will affect the stimulation effect.Due to the complexity of acid-rock heterogeneous reaction,experimental methods are often difficult to meet the requirements of formation conditions.Traditional numerical simulation methods have the disadvantages of complex boundary processing and low parallel efficiency.In recent years,the lattice Boltzmann method(LBM)has gradually entered everyone's field of vision.Compared to the macroscopic model,it does not need to discretize the N-S equations before calculating the fluid dynamics.Compared to the microscopic model,it only needs to perform evolutionary calculations to obtain results that are consistent with the macroscopic laws.It has the advantages of simple structure,high computational efficiency and easy handling of boundary conditions.It is suitable for solving the problem of acid-rock heterogeneity reactive in porous media.In this paper,we use the sandstones of blocks A,B,and C in an oil field to study the heterogeneous reaction mechanism of acid-rock.LBM basic equations,boundary conditions,and artificial porous media generation methods are selected.A flow,heat transfer,and mass transfer model is established to simulate the heterogeneous reaction between the mud acid system and the sandstone in porous media.The major achieved is as follows:(1)Acid-rock heterogeneous mechanism is explored through experiments,including the reaction of soil acid systems with sandstone reservoir minerals,the main interaction pattern and mode of HF dissolved minerals,the catalysis and mode of HCl,the dynamic mechanism of acid-rock heterogeneous reaction.(2)According to the flow parameters of the acid,the corresponding evolution equation,balanced distribution function and boundary condition are selected.Thus,a LBM based flow model of acid in the pipeline is eastablished,the model's error and stability are explored.(3)Artificial random porous media generation method is selected,simultaneous REV model is used to improve the simulation efficiency and stability of flow model.Thus,a LBM based flow model of acid in porous media is eastablished.(4)According to the flow model,the matching mass transfer model and heat transfer model are selected.In combination with the acid-rock heterogeneous reaction mechanism,the expressions of relevant parameters in the model are determined.Thus,a LBM based model of acid-rock heterogeneous reaction in porous media is eastablished.The model is solved by Matlab to obtain the distribution of temperature,concentration of each substance,porosity,and permeability.This study aims to develop a LBM based model for the heterogeneous reaction of sandstone minerals and mud acid system in porous media,carries out simulation studies,and demonstrates the heterogeneous flow mechanism of acid-rock in porous media from mesoscopic scales.