IMPLEMENTATION OF CYCLIC STEAM STIMULATION TO ENHANCED OIL RECOVERY FOR A SUDANESE OIL FIELD: CASE FULA NORTH EAST FIELD

Abstract

- Tertiary oil recovery or Enhanced Oil Recovery (EOR) is the injection of fluids or energy to the reservoir to improve oil recovery and it can be applied at any phase of oil recovery including primary, secondary, and tertiary recovery and its objective is to increase oil recovery from reservoir depleted by secondary recovery such as water flooding. Steam Injection is to inject steam to heat the oil to higher temperatures and to decrease its viscosity so that it will be more easily to flow; cyclic steam stimulation (CSS) consists of three stages and happened in single well, CSS is particularly attractive because it has quick payout, however, recovery factors are low (10-40%) from Original Oil in Place (OOIP). In a variation, CSS is applied under fracture pressure. Fula North Field (FNE) reservoirs are highly porous (~30%), permeable (1-2) Darcy and unconsolidated in nature. the fluid properties include viscous crude with 15 to 17.7 API. Corresponding viscosity are in the range of (727 and 3800) cp at reservoir conditions and the current recovery factor is 3.6 %. The objective of this paper is to illustrate and analyze the performance of CSS phase’s implementation starting from the first pilot up to full field scale through different stages. In this paper overall analysis for the CSS performance implementation including the injection parameters in FNE field will be presented furthermore detail comparison between CSS cycles and cold production discussed. Finally the challenge for this project has been listed; Advanced Thermal EOR Simulator from Computer Modeling Group (CMG) software has been used to propose the location of the new wells and to compare between CSS and Cold case for FNE Field. The result showed that the CSS is very successful and the average oil rate is almost 1.6 times compared to cold production, the CSS only can increase the recovery percent from 32.5 to 34.2% which makes it more attractive method as development scenario for FNE oil field, and the new wells drilled with 100 % success ration.