Screening and optimisation of water/foam/gas injection EOR scenarios in a fractured reservoir

Abstract

Primary sweep efficiency in carbonate reservoirs is low due to the low contribution of the matrix in production. Also, due to unfavourable mobility ratio, secondary recovery is not also effective. Hence, design and application of an effective enhanced oil recovery method is essential to improve recovery. Different methods such as water injection, gas injection, chemical injection, thermal, and a combination of these methods such as water alternating gas (WAG), simultaneous WAG (SWAG), selective simultaneous WAG (SSWAG), foam injection, and foam-assisted WAG (FAWAG) are applied to improve the recovery efficiency in naturally fractured reservoirs. In this paper, selection of the best EOR method and well pattern for a naturally fractured reservoir is studied to reach the highest net present value (NPV) and field oil recovery efficiency (FOE). Results showed that the FAWAG process in a five-spot well pattern with 22.7% oil recovery efficiency is the best technical and economical method.Keywords: carbonate reservoirs; water injection; gas injection; foam injection; well pattern.Reference to this paper should be made as follows: Bagrezaie, M.A. and Pourafshary, P. (2016) 'Screening and optimisation of water/foam/gas injection EOR scenarios in a fractured reservoir', Int.