In this paper the path of novel software development is described. The aim of that research is the simulation of near-wellbore zone treatment. The core of the simulator is the numerical solution of the system of linear equations. Equations describe hydrodynamic processes and chemical homogenous and heterogeneous interaction in porous media. The simulator implements the ability to simulate the geometry of the near-wellbore zone for different well constructions (horizontal well, fractures wells and multi-stage fractures). Algorithms and methods have been developed for modeling the properties of the rock and its mineralogical composition, as well as for modeling formation damage distribution. In addition to solving the system of equations for porous media around the wellbore, a module was implemented for calculating the movement of fluids along the well casing from the wellhead to the bottomhole. This module takes into account the internal structure and geometry of the formation penetration and heat movement. The simulator implements the ability to simulate acid compositions with various types of diverters based on modeling the flow of non-Newtonian fluids in the well and reservoir. Special important addition is heat transfer modeling. The developed simulator is focused on optimizing the treatment design in field conditions. Therefore, optimization modules were additionally developed based on multivariate calculations and optimization algorithms, taking into account the economic model and the forecast of the extra oil production module. An adaptation module has been developed to search for empirical coefficients characteristic of an object based on previously carried out treatments and laboratory studies. The article presents comparative calculations of the implemented software package with simplified models. It allows to substantiate and assess the significance of the implemented additional features. Examples of calculations for various types of wells and conditions are given. In addition, it was taken into account previously conducted laboratory experiments and real treatment experience. Computational experiments were considered and carried out on the following problems: the effect of the temperature of the injected fluid on the treatment efficiency, the distribution of the acid injection front for wells with horizontal construction, the diverters influence, the effect of acid injection volumes in wells with hydraulic fractures, the effect of acid composition injection volumes on the treatment efficiency in carbonate and sandstone reservoirs. The existing problems and prospects for the development of modeling the well treatment are analyzed and identified with account taken of the experience of developing the simulator.
References
1. Maltcev A., Shcherbakov G., The development of the trends in formation damage removal technologies in sandstone reservoirs, SPE-199321-MS, 2020, https://doi.org/10.2118/199321-MS
2. Shcherbakov G., Yakovlev A., Groman A., Maltcev A., The development of chemical stimulation method trends in sandstone reservoirs, SPE-196992-MS, 2019, DOI: https://doi.org/10.2118/196992-MS
3. Bulgakova G.T. et al., Mathematical modeling and optimizing the design of matrix treatments in carbonate reservoirs (In Russ.), Nauchno-tekhnicheskiy vestnik OAO “NK “Rosneft'”, 2014, no. 2, pp. 22–28.
4. Bulgakova G.T., Kharisov R.Ya., Sharifullin A.R., Pestrikov A.V., Optimizing the acidizing operations of horizontal wells in carbonate reservoirs (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2013, no. 6, pp. 102–105.
5. Sevougian S.D., Lake L.W., Schechter R.S., KGEOFLOW: A new reactive transport simulator for sandstone matrix acidizing, SPE-24780-PA, 1995, DOI: https://doi.org/10.2118/24780-PA
6. Filippov D.D., Vasekin B.V., Mitrushkin D.A., Multiphase filtration modeling of complex structure reservoirs on dynamic adaptive PEBI-GRID (In Russ.), PRONEFT''. Professional'no o nefti, 2017, no. 4(6), pp. 48–53
7. A. Blonsky A., Mitrushkin D., Kazakov A. et al., Development of acidizing simulator for sandstone reservoirs, SPE-94566-MS, 2020, https://doi.org/10.2118/94566-MS
8. Oda M., Permeability tensor for discontinuous rock masses, Geotechnique, 1985, vol. 35, рр. 483–495.
9. Barenblatt G.I., Zheltov Yu.P., Kochina I.N., On the basic concepts of the theory of filtration of homogeneous fluids in fractured rocks (In Russ.), Prikladnaya matematika i mekhanika – Journal of Applied Mathematics and Mechanics, 1960, V. XXIV, no. 5, pp. 852–864.
10. Mal'tsev A.A., Sandstone (polymictic) acid treatment design optimization based on complex approach (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2021, no. 6, pp. 80–83, DOI: 10.24887/0028-2448-2021-6-80-83.
