The Coniston and Novara Development in Western Australia - Offshore Challenges met with Solutions

Abstract

Abstract The development of heavy oil accumulations presents difficult engineering, technological and geological challenges that need to be overcome to produce economically viable projects. Even a large oil accumulation can be deemed unattractive for development in cases that combine a high cost environment with complex geological setting and unfavorable fluid dynamics. This paper highlights the challenges and presents the subsurface solutions that unlocked the value of an offshore heavy oil accumulation, 32 years after it was first discovered. Within the context of the overall development plan, the paper describes: The design of the offshore well test that delivered 11,244 bbl/d 15.7°API oil and proved the production capacity of the reservoir and the conceptual well design. Workflow for confirming the existence of a compositional gradient and characterization of a biodegraded oil column. A novel approach to evaluation of inflow control devices (ICD) and its implementation in the well design. An ICD modelling tool developed specifically for direct comparison of different ICD geometries. The paper also presents the field history to date – from the early failures in recovering hydrocarbons using conventional methods, through to the enabling technologies that made Coniston and Novara a viable project.