Abstract
Laboratory investigations and field applications have proved steam drive to be an effective enhanced oil recovery method for reservoirs of moderate and heavy oil viscosity. This experimental study was undertaken to investigate, combine and compare the performance and productivity of water, steam, alkaline steam, surfactant steam, and surfactant alkaline steam floods through vertical and horizontal wells. To achieve the objectives of the study, two experimental models (vertical and horizontal) are designed and built. Identical porous media, reservoir fluids (crude oil and formation water), steam, chemicals, and injection/production conditions are used and/or applied.
The results of the study showed that horizontal wells are better candidates for waterflooding than vertical ones, when the same pore volume of water are injected in the reservoir. Steam and chemical steam (alkaline steam, surfactant steam, and surfactant alkaline steam) floods recovered more oil when applied through horizontal wells than through vertical ones. In addition, chemical steam floods recover more oil than conventional steam drive for both applications of vertical and horizontal wells. The increment of oil recovery due to application of horizontal wells instead of vertical ones may be 10.27 % IOIP for steam flood and almost 17.7 % IOIP for surfactant alkaline steam flood.
The displacement efficiency of oil recovery through horizontal wells is higher than that through vertical wells for steam flood by almost 25 %, for alkaline steam flood by almost 33 %, for surfactant steam flood by almost 37 %, and for surfactant alkaline steam flood by almost 48 %. The proposed techniques of chemical steam floods have important implications for improving oil recovery from current water flood and steam projects, since they combine the advantages of both chemical and thermal recovery methods.
