INVERSE IMMISCIBLE GAS INJECTION BELOW OIL-WATER CONTACT FOR A RESERVOIR WITH LOW GAS OIL RATIO
Gas injection is one of the most common forms of enhanced oil recovery, applied offshore, onshore, as well as unconventional reservoirs. Inverse hydrated gas injection method is a coined term to describe gas injection below oil water contacts, owc. The amount of dissolved gases increases from oil – water contacts to gas – oil contacts, goc. Production of oil with low GOR is highly problematic because of low mobility; it is therefore necessary to increase the oil mobility so as to increase oil recovery. To achieve improved oil recovery, gas injection was considered under two different scenarios for x2.00 reservoir of Ologobiri field. Simulation study showed that an incremental oil recovery of 30% of STOIIP by immiscible gas injection. Based on the simulation study carried out, a 10 – year, 2020 to 2030, of sustained immiscible gas injection at 3000 sm3/d, pushed a peak daily production rate of about 120 sm3/d to the surface. Daily oil production progressively dropped to 78 sm3/d, and produced gas oil ratio rose progressively. During the first year period of gas injection, reservoir pressure increased by about 25 bar and consequently dropped progressively. Based on the encouraging result from simulated gas injection, the operator may decide to expand drilling of new oil well producers.