Development of the material balance model for consideration of wells productivity index changes

The material balance model in the form of an analytical capacitance resistive model (CRM) is increasingly being used for mathematical modeling of oil field development. The original formulation of the CRM model lacks the capacity to account changes in productivity index of producing wells. This reduces the applicability of this model for group of wells with operations on productivity intensifying. The article contains the modification of the CRM model which allows to take into account non-stationarity of the productivity index. The test calculations showed that the modified CRM model allows to reproduce dynamics of well production rate with significant changes of the productivity index.