The article describes the main ideas of the integrated approach to the use of matrix-stimulation methods in the oilfields with sandstone reservoirs. LLC Gazpromneft scientific and technology center as the basis of the project "Optimal matrix stimulation methods" undertook the joint study. The project objective is to increase the efficiency of matrix stimulation by introducing advanced techniques for automized well selection and calculating the design of acidizing based on mathematical modeling.

The article describes the main ideas of the integrated approach to the use of matrix-stimulation methods in the oilfields with sandstone reservoirs. LLC Gazpromneft scientific and technology center as the basis of the project "Optimal matrix stimulation methods" undertook the joint study. The main tasks of the project are related to the development of software tools such as: the tool for diagnosis of formation damage type in near-wellbore zone, the tool for selecting the optimal technology of near-wellbore treatment, the tool for matrix stimulation design with the possibility of it’s optimization.

In this paper it is described the approach of constructing the design of acid treatment and the tools of the software designed to solve this problem. The developed simulator includes a hierarchy of calculation modules that differ in the degree of detail of the physical effects. In addition, a number of engineering modules was developed as a part of the simulator: well data preprocessing module, history-matching module, optimization module. The mathematical models in the simulator take into account the multicomponent composition of the liquid, an arbitrary number of minerals in the solid phase, and an arbitrary number of kinetically controlled heterogeneous and homogeneous chemical reactions. Moreover, the models take into account the non-Newtonian rheology of diverters and the thermal effects during chemical reactions. The geometry of the well and hydraulic fractures can be explicitly resolved on 3D Voronoi grid in the framework of developed approach. The developed algorithms were tested by real data. It is demonstrated that precipitation resulting from secondary and tertiary reactions can have a determining effect on the result of acid treatment. The article presents the results of simulation acid treatment in a vertical well with a colmated hydraulic fracture. It is shown that acid treatment led to complete restoration of the fracture conductivity. The results of the two acid treatments analysis are also presented. When analyzing the first work it was possible to determine the reasons for the unsuccessful treatment by the adaptation model to the production data and to select an acid composition that provided maximum efficiency. When analyzing the second treatment for the well, an analog was found on which acid treatment was performed. The model parameters were adapted to the results of acidizing for the analog, and the parameters obtained as a result of the adaptation were used to simulate treatment at the original well, which led to the agreement of the simulation results with the real data. Then, it was shown under the result of design optimization that more intensive acid treatment should have been performed on the original well.

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