GAS-OIL GRAVITY DRAINAGE IN A FRACTURED R ESERVOIR - EXPERIMENTAL STUDIES OF MECHANISMS OF THE BLOCK TO BLOCK PROCESS

In order to improve the understanding and the modelling of the flow me chanisms between the blocks of fractured reservoirs, a series of mainl y experimental studies has been carried out in the Reservoir Division of Elf Aquitaine Production concerning capillary continuity and reimbi bition during the cascade drainage. In simple experiments, clear obser vations of the phenomena have allowed identification of the essential points in the block to block process, such as conditions and character istics of capillary continuity, and its effects on flow kinetics. Nume rical simulations of these experiments have pointed out that Killough' s formulation of capillary pressure hysteresis does not adequately sho w the reimbibition process on a block being simultaneously drained. Fu rther modification of two-phase flows in a porous environment is neces sary to simulate the reimbibition process and consequently the cascade drainage on a column of blocks.