Mathematical Modeling of Oil Well Nonstationary Work Taking into Account the Permeability Nonequilibrium Phase

About the authors:

Alexander V. Ivanov, Postgraduate Student, Department of Applied and Technical Physics, University of Tyumen; Chief Specialist, Tyumen Oil Research Center; avivanov8@tnnc.rosneft.ru

Sergei V. Stepanov, Senior Expert, Tyumen Petroleum Research Center, Tyumen, Russia; Dr. Sci. (Tech.), Professor, Tyumen Petroleum Research Center Specialized Department, School of Natural Sciences, University of Tyumen, Tyumen, Russia; svstepanov@tnnc.rosneft.ru

Abstract:

As follows from the actual data of operating wells, the dynamics of their technological indicators are very often characterized by an expressed nonmonotonicity. Today the problem of physical and/or technological factors contributing to such nonmonotonic dynamics of well work has not been studied yet, largely due to the complexity of detailed mathematical modeling of wells. Thus, the experience of mathematical modeling of individual wells (even using sectoral models) typically demonstrates the impossibility of commercial hydrodynamic simulations with a sufficient degree of detail to simulate complex nonmonotonic dynamics of technological indicators. In this regard, it is necessary to use specialized software.

Today, there are specialized software to simulate the work of individual wells; however, the complexity of multiphase filtration near wells, which often cannot be explained from the standpoint of traditional physical and mathematical models, necessitates the development of original software. In particular, this concerns the effect of nonlinear effects and nonequilibrium on the relative phase permeability (RPP), while the non-equilibrium factor is much less studied.

This paper observes the results of applying the developed software for numerical analysis of oil well’s operation on the reservoir BV8^1-3 of Samotlor Field. The computer program is created on the basis of physical and mathematical model describing the filtration of oil and water in the reservoir, including the nonequilibrium RPP model of G. I. Barenblatt.

Barenblatt’s nonequilibrium filtration model involves the use of relaxation time. Since relaxation time values do not have unambiguous evaluation, this work presents a sensitivity analysis with different relaxation times. The results show that the examined system reservoir-fluid relaxation time is approximately 100 days.

This work shows the research results of well water cut dynamics depending on its operation mode and the reservoir characteristics. In all cases the nonequilibrium RPP leads to expressed pulsations of water cut.

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