Simulation of acid exposure on a porous medium

The study deals with a problem of acid treatment of the porous medium. It is known that the acid effect on the oil reservoir is a widely used technology intensification of hydrocarbon production and design of parameters such as the concentration of acid,its volume and injection rate havea significant impact on commercial performance. In this regard, the issues addressed in this paper arerelevant today and demand. There is a mathematical model of the two-phase (oil and water) three-component (oil, water and acid) flow of liquids in porous media, taking into account changes in the filtration properties of the skeleton as a result of the interaction the reagent with the rock skeleton. We investigatea question of phenomena which associated with different rates moving fronts of active component and water saturation is produced. The problemof selecting the optimum injectionrate of the active agent into the coreis discussed. There is a comparison of numerical results with experimental data.
Materials and methods
To calculate changes in porosity and permeability as a result of interaction the acid with rock skeleton the model of "bundle" of cylindrical capillariesof different radii is applied. During analyzing the results, which characterize the propagation velocity fronts of different components flow in a porous medium, used two-phase flow model, proposed by Buckley and Leverett. The problem is solved by the method of control volumes on a uniform grid using parallelization technology OpenMP.
Results
The study presents a model of oil displacement by water using an acid stimulation in which to describe the changes in the porosity and reservoircharacteristics the model of an ideal porous medium as a bundle of capillaries of different radii is used.The analysis of phenomena associated with different rates moving fronts ofactive component and water saturation is produced. It’s shown that the model proven it’s effective and allows predicts the optimum feed rate of acid solutioninto the sample, providing a minimum consumption of reagent.
Сonclusions
The described technique for determining the optimal injection rate of the acid solution in the core can beused for the selection of filtration mode in acidizing of the near-wellbore zone in real oil fields.