Organic Oil Recovery - Resident Microbial Enhanced Production Pilot in the Scott Field (UKCS)

Summary Introduction: CNOOC has been involved in a pilot study to determine the efficacy of Organic Oil Recovery (OOR, a unique form of microbial enhanced oil recovery) as a means of maximising oil recovery from its Scott field. CNOOC’s operated Scott asset came on stream in 1993 and produces crude oil and natural gas from the Scott, Telford and Rochelle fields. Scott is located approximately 188 kilometers northeast of Aberdeen in 142 meters of water. Methods, Procedures & Process: Organic Oil Recovery harnesses microbial life already present in an oil-bearing reservoir to improve oil recovery through changes in interfacial tension increasing the oil’s mobility and improving recovery rates and reservoir wettability. These changes could increase recoverable reserves and extend field life through improved oil recovery with negligible topsides modifications. The pilot injection is implemented by injecting a specific nutrient blend directly at the wellhead with ordinary pumping equipment. The well is then shut-in for an incubation period and thereafter returned to production. Results, Observations & Conclusions: During initial laboratory testing of two Scott target wells the reservoir showed a diverse and abundant resident ecology which has been proven capable of undergoing the necessary characteristic changes to facilitate enhanced production. A pilot test was completed on well J17 in July 2020 and due to this application, both an ecology and production response has been proven. In addition to this response a drop in H₂S in both the Oil and Gas phase has been observed. The full method of implementation of the pilot test will also be discussed in detail and will include any challenges and/or successes in this area. The initial starting ecology of the wells will be demonstrated and compared to the ecology post-pilot. Additionally, a comparison of production and H₂S figures prior to and post the pilot implementation will be detailed. A correlation will be demonstrated between changes in ecology and an increase in production and a reduction in H₂S.