Abstract:
Thermal recovery methods and especially steam flooding have long been considered as the most effective methods to extract heavy oil reservoirs. These highly viscous hydrocarbon deposits are proven to constitute a huge proportion of total world oil reserves. Large volumes of heavy oil in Fula North East Oilfield SUDAN have a high viscosity (2019 centipoise at reservoir temperature 43°C) are located in heterogeneous porous media containing high permeable wormholes or non-permeable shale barriers.
The main objective of this study is to investigate the feasibility of using Steam Flooding in Fula North East (FNE) - Sudan. FNE reservoirs are high porosity (30%), permeability (1000-3500 mD), and unconsolidated in nature. the fluid properties include a viscous crude range from 15 to 17.7 API. The corresponding viscosity is 2019 cp at reservoir conditions (Temperature 43C and Reservoir Pressure 571 Psi).
The research-based on physical simulation to scale of a Steam flood using one core sample from well#FNE-135 to represent the reservoir, steam core flood experiments were conducted By (STEAMFLOOD 700) station in Petroleum Labs, Research and Studies (PLRS), to study the efficiency of Steam flood in order to decrease the viscosity and improve oil recovery. The core sample was aged with crude oil at 43°C for 21 days to conduct the best conditions before the experimental.
The experimental of steam flooding in core scale showed that the oil viscosity decreasing from 2019 cp at reservoir temperature 43° C to 1.5cp due the steam injection, which the mobility ratio was improved, furthermore, the residual oil saturation reducing from 80.1% by water flooding to 53.8% by steam injection, as well, the recovery factor RF increasing by steam flooding from 8.6% to 30.1%, moreover, the displacement sweep efficiency ED improved from 9% by cold production to 38% by steam flooding, also the experiment showed clear incremental in formation volume factor due to effect of the steam injection compared to cold production.
