Simulation Study on Gravity Assisted Simultaneous Water and Gas (GASWAG) Injection for Thin Oil Rim

Thin oil rim is thin reservoir oil column that has an overlying gas cap and underlying
aquifer. Oil rim reservoir is always associated with coning problem, gas smeared and
oil lost into gas cap that will reduce the oil recovery factor. One of the effective
solution for the thin oil rim problem is gravity assisted simultaneous water and gas
(GASWAG) method. The objective of this study is to investigate GASWAG method
by changing the possible parameters that affected the process of the GASWAG
method in order to maximize the oil production from thin oil rim and to conduct an
economic feasibility study. The study is related to gas flooding, water flooding and
GASWAG method. A model of GASWAG will be generated using Black Oil
Simulator in computer laboratory. The parameters that changed in the GASWAG
process are type of well producer, location of the producer, salinity of brine injection,
mobility ratio, injection rate of fluid injected and well spacing. The most suitable
producer for GASWAG process is a horizontal well that located in the middle of the
oil column. Low water injection rate and high gas injection rate give favorable
result. Excellent result was presented by the existence of polymer in the water
injection at the gas-cap. The salinity of brine injection is insignificant for GASWAG
process.