Resident Ecology Production Enhancement Success in the North Sea

Abstract A Company in the United Kingdom who operates a field in the North Sea has been involved in a pilot study to determine the efficacy of Organic Oil Recovery (OOR) as a means of maximising oil recovery. This paper shows the process, planning and execution of the application of the technology as well as results of the OOR Pilot Test. Organic Oil Recovery (OOR) is a unique enhanced oil recovery process. The fundamentals of the technology are based on the activation of microbial life resident in oil reservoirs with the purpose of increasing oil production. The technology can dramatically improve the mobility of oil trapped in tight pore spaces or on the oil-bearing rock to improve ultimate oil recovery. This Pilot Test (In-Situ Microbial Response Analysis – ISMRA®) is implemented by injecting a reservoir specific nutrient blend directly at the wellhead with typical pumping equipment. The well is then shut-in for an incubation period and thereafter returned to production. Another important feature of the technology is its ability to tackle the root cause of H₂S formation by targeting specific species of microbes to outcompete Sulphate Reducing Bacteria (SRBs) which are a primary cause of this gas's formation. During initial laboratory testing, Field X target wells showed a diverse and abundant resident ecology which has been proven capable of undergoing the necessary characteristic changes to facilitate enhanced oil recovery in the Field X reservoir. An important observation was that the ecology was initially dominated by Sulfidogens. The Pilot Test was undertaken in Q4 2023 and showed an average 30-35% increase in overall production. The full method of implementation of the Pilot Test, from sampling to injection, will be discussed in detail in this paper, and will include any challenges and/or successes in this area. The initial state ecology reports of the wells are demonstrated and compared to that of post-Pilot Test ecology reports, which proved a substantial shift towards the targeted ecology which resulted in a >99% decrease in sulfidogens. This will be substantiated by production figures for the well prior to the Pilot Test as well as after the pilot implementation. A correlation is demonstrated between changes in ecology and an increase in production.