STUDY OF FACTORS INFLUENCING THE OIL RECOVERY BY GAS GRAVITY DRAINAGE FROM MATRIX BLOCKS IN NATURALLY FRACTURED RESERVOIRS USING NUMERICAL SIMULATION TECHNIQUE

Gas gravity drainage is an important oil recovery mechanism in matrix block of fractured carbonated reservoirs. Hence it is critical to study different factors that are influencing this process. Since there is no exact analytical solution the problem of gravity drainage, the study of factors influencing this process can’t be done using approximate solutions proposed to date. Therefore, laboratory or numerical simulation experiments need to be carried out. By the way the laboratory option is usually not feasible due to the need to tall matrix blocks and high costs associated with laboratory. This justifies the use of numerical simulation which is the subject of this study. In this work basic rock and fluid properties along with gas-oil relative permeability and capillary pressure data from some Iranian fractured carbonated oil reservoirs were used as input to a reservoir simulator to generate 72 cases of oil recovery by gravity drainage. The goal was to investigate the factors affecting the process using numerical simulation experiments. The factors are block height and rock and fluid properties. The effect of these factors on both ultimate recovery and rate of recovery is discussed.

Keywords:

Fractured reservoirs , porous media , gravity drainage , simulation , block height , rock , fluid