In-depth Permeability Modifier for Improvement of Sweep Efficiency in a Heterogeneous Oil Reservoir: A Review

摘要

This study reviews and assessed some of in-depth permeability modification techniques used in the industry with regards to improving conformance problems in heterogeneous oil reservoirs. Reservoir conformance problems frequently limit the success of many of water and chemical EOR flooding projects. Basically, there are many types of conformance problems and many different conformance improvement techniques. The challenge is to properly identify and then to select a suitable conformance improvement technology. Conventionally, In-situ gels have been widely used and placed near the well-bore of injectors or producers to improve conformance. However, in heterogeneous reservoirs permeability variation extends throughout the whole reservoir structure and in some cases presence of cross-flow between adjacent layers limits the effectiveness of in-situ gels. Alternatively, conformance improvement has been obtained by continuous polymer injection. This method still by-passes significant amounts of oil as evidenced from a number of recent reports. Preformed cross-linked gel particles have become an interesting technology to overcome some of the distinct drawbacks of in In-situ gels and polymer flooding. Although, this method show promising oil improvement, lack of in-depth knowledge is available as well as their mechanisms to plug rock pores are not fully understood. It's the aim of the study to review the reservoir conformance problems as well as conformance improvement techniques. The focus has been given to studies of current in-depth permeability modifiers and highlight chemistry, applications and inadequacy of these technologies. Finally we briefly outline the major challenges, which must be addressed to successfully implement preformed cross-liked particles in improving sweep efficiency applications are highlighted.