Chemical EOR - A Multidisciplinary Effort to Maximize Value

Abstract

Management Production from oil fields can be increased by enhanced oil recovery (EOR) techniques. Among several other EOR methods, the injection of chemicals has been studied since the 1970s. In that time, anionic polyacrylamides (PAM) have proven to be efficient viscosifiers for moderate field conditions to reduce mobility of the displacement fluid, thus increasing reservoir sweep efficiency. Surfactants mobilize oil that is trapped in formation rock pores by lowering the oil/water interfacial tension. Polymer flooding is now considered an established technology, which is applied on a commercial scale in several countries. In contrast, the commercial use of EOR surfactants is still limited despite more than 50 years of research history in this area. This can be partly explained by the technical complexity of EOR surfactant projects and the higher cost. The implementation of a chemical EOR (cEOR) project is often a significant endeavor that not only poses technical challenges but also represents substantial financial risk. In recent years, cEOR projects also target challenging conditions such as high temperatures, high salinity, and demanding locations such as offshore fields. A multidisciplinary and integrated approach is vital to managing technical, regulatory, and economic challenges with a team of geoscientists, engineers, chemists, and mathematical modelers working together to achieve an increase in incremental oil recovery at the lowest total cost of ownership. From Laboratory to Full Field Once the operator has verified that injection of chemicals is a viable option to enhance oil recovery in one of its assets, a laboratory-screening program will start to identify a suitable chemical solution that not only will perform under specific reservoir conditions but also meet financial targets. The principal workstreams of a cEOR project are illustrated in Fig. 1. EOR-specific application test work is needed, such as rheology evaluations for polymers, or phase-behavior and interfacial-tension measurements for surfactants. The quality of the work will rely considerably on the collaboration of an experienced multidisciplinary team mainly because the experimental evaluations cover a broad range of knowledge fields such as chemistry, physical chemistry, and reservoir and petroleum engineering.