Determination the initial value and change behaviour of the reservoir permeability via two field measurements

Abstract

The paper proposes a technique for interpreting the results of hydrodynamic studies of volatile and non-volatile oil wells at two steady-state regimes in order to determine the initial value and coefficient of variation in effective permeability of the reservoir. It is developed based on a binary filtration model, where the hydrocarbon system is represented as consisting of two pseudocomponents and two phases, between which mass transfer of hydrocarbons takes place. The proposed methodology requires well flow rates measured at two different steady-state well conditions for two different reservoir pressures and thermodynamic data of the hydrocarbon system at reservoir conditions. The methodology has been validated using examples of hypothetical volatile and non-volatile oil reservoirs at different rock deformation ratios and for nondeformable reservoirs. It has also been tested under different development stages and measurement conditions. For this purpose, a computer simulation of the oil reservoir depletion process was carried out, the results of which were used as well test data. Satisfactory accuracy and reliability of the outlined approach has been established. As deviations of calculated values of required parameters from their actual values did not exceed 8%.