Reservoir Simulation Study of Cyclic Low Salinity Waterflood at a Line-Direct Pattern in Rub al Khali Basin Ratna Widyaningsih (a*), Edgie Yuda Kaesti(a), Suwardi(a), Adam Raka Ekasara(b), Fahrur Rozi(a), Dhika Permana Jati(a)
a) Petroleum Engineering Department, UPN Veteran Yogyakarta, Indonesia
b) Geology Engineering Department, UPN Veteran Yogyakarta, Indonesia
Abstract
The Rub Al Khali Basin, located in southern Saudi Arabia, is a deep (7350 ft) and carbonate reservoir with an average porosity of 21%, permeability of 23.3 mD and formation water salinity of 47,091 ppm. The produced oil has an API gravity of 42.1. Cyclic Low Salinity Waterflood (CLSW) combines Cyclic Waterflood Injection with Low Salinity Water Injection (LSWI) to maximize oil recovery by combining pressuring and de-pressuring cycles and altering wettability to more water-wet conditions. This study evaluates CLSW^s effectiveness in enhancing oil recovery using black oil simulations on tNavigator. The injection scenario includes sensitivity of injected water salinity, cyclic periods of 1:1 and 2:1, and variable injection rates of 1400, 1200, and 1000 stb/d. Cumulative oil production in the 1:1 cyclic period with injection rates of 1400, 1200, and 1000 stb/d reached 17.31, 16.85, and 16.3 MMSTB, respectively, while in the 2:1 cyclic period it reached 16.85, 16.38, and 15.8 MMSTB. Clearly seen that the 1:1 cycle period provided higher oil recovery due to faster pressuring and de-pressuring. It is concluded that for this pattern, CLSW with shorter cyclic periods results in better oil recovery in this reservoir.
Keywords: Cyclic Low Salinity Waterflooding, Cyclic water injection, Low salinity
