Effect of Dip Angle on Recovery Factor During Free Fall Gravity Drainage and Forced Gravity Drainage

Summary Gravity drainage is an effective recovery mechanism in the majority of fractured reservoirs. In this study, the effects of matrix and fracture orientation, and 0–20 degrees’ deviation from vertical alignment on recovery factors were investigated during free fall gravity drainage (FFGD) and forced gravity drainage (FGD). Experiments were conducted in a novel fractured sand pack with a different number of fractures. Water was used as the wet phase, and during the FGD process, nitrogen at a constant rate of 10 cc/min was used as the non-wet phase. Results demonstrated that final recovery factors in FGD were almost 3% more than FFGD experiments. Also, it is found that depend on the number, position, and orientation of fractures, the final recovery factor by increasing deviation from vertical alignment can increase or decrease. In other words, the position of matrix and fractures and their orientation have an important effect on the rule of fluid flow mechanisms and enhance oil recovery.