Key Learnings from First 2 Years of a Full Field CSS Development in Oman

Abstract

The "A" East Haradh formation contains a 200 m thick oil column of highly viscous oil, with viscosity ranging from 200 to 400,000 cp. Due to the high viscosity, first production was considered only possible using thermal EOR techniques, starting with Cyclic Steam Stimulation (CSS). The field has now been in operation for more than two years, with a number of wells already into a third CSS cycle. This paper will focus on the key learnings derived during this initial operations phase of CSS in "A" East Field including, amongst others, key trial results on different well completions and artificial lift systems combined with new insight into the reservoir architecture. In addition, reservoir performance management is being streamlined through the development of a structured approach to the CSS planning and using dedicated visualisation. Automated Exception Based Surveillance "triggers" are currently being developed to efficiently address any deviation from the operating envelopes and further optimise the recovery from this 81 well CSS development. Based on the very encouraging performance to date, the company has already sanctioned a further 34 well CSS expansion of the current development with drilling scheduled to commence in 2016.