Front-end engineering practice of in-situ MEOR applications

In this paper, the operational experience from an in-situ MEOR application is presented including a general evaluation leading to lessons learned and guidelines for supporting front-end engineering (FEE) of similar applications. The importance of working in a well-integrated team covering various aspects on microbiology, reservoir and operation engineering in all work packages is obvious. Considerable time is needed to align on the terminology and working interaction between science and engineering of various disciplines. A general breakdown structure that can be applied in MEOR projects is presented. An update of screening criteria is proposed and emphasis on minimum sulfate content in formation water and on the coexistence of carbonates in reservoir rock is suggested as requirements for successful application of in-situ MEOR. The major risks determined prior to operational phase of the project and their mitigations are discussed in detail. Due to its relevance, higher probability and time-consuming mitigation efforts, the risk of souring is discussed separately and its assessment is summarized based on field data. The details of a surface set-up as well as a logistic concept that can be used in insitu MEOR operations is presented confirming the easy-to-apply characteristic. A list of the measurements and analyses that can be applied for monitoring of MEOR applications is also provided. MEOR is in general perceived to be a cost-effective EOR method but field experience shows that this impression can be delusive when considering all potential expenses, including R&D and risk mitigation costs in mature/brown fields.