Abstract
The Lower Miocene sandstone reservoir in Rang Dong Field, within Block 15-2 offshore Vietnam, has continuous oil production since 1998. Since achieving peak rates in 2002, oil production has steadily declined despite efforts to improve oil recovery. Numerous production improvement techniques were studied with focus on the potential applications of hydrocarbon gas enhanced oil recovery (HCG-EOR). Initial feasibility studies on HCG-EOR indicated potential applicability to addressing the production decline.
The HCG-EOR Pilot Test program, designed with appropriate monitoring plan, was implemented in 2011 coupled with a water-alternating-gas (WAG) scheme. The HCG-EOR pilot test yielded positive EOR impacts such as oil rate increase and water cut reductions concurrently with oil property changes. Reservoir saturation logging on a well between an injector and a producer indicated reduction in residual oil saturation, which is encouraged by injected gas encroachments, in multiple layers. These observations are considered positive indications of the effectiveness of HCG-EOR in a field scale application.
This paper presents the initial feasibility study results, the field findings to date of the HCG-EOR Pilot Test including designs, monitoring plan, results, and the post evaluation toward achieving the HCG-EOR full field scale implementation.
