The Pyrenees development comprises the concurrent development of three oil and gas fields: Ravensworth, Crosby and Stickle. The fields are located in production licenses WA-42-L and WA-43-L, offshore Western Australia, in the Exmouth Sub-basin. The development will be one of the largest offshore oil developments in Australia for some time. It is a complex subsea development consisting of a series of manifolds, control umbilicals and flexible flowlines tied back to a disconnectable floating production, storage and offloading (FPSO) vessel. The development involves the construction of 17 subsea wells, including 13 horizontal producers, three vertical water disposal wells and one gas injection well. The project is presently on production with first oil achieved during February 2010.
This paper gives an overview of the field development and describes the engineering and technologies that have been selected to enable the economic development of these fields.
The Pyrenees fields are low relief, with oil columns of about 40 metres in excellent quality reservoirs of the Barrow Group. Two of the fields have small gas caps and a strong bottom water drive common to all fields is expected to assist recovery. The oil is a moderate viscosity, low gas-to-oil ratio (GOR), 19°API crude. Due to the geometry of the reservoirs, the expected drive mechanism and the nature of the crude, effective oil recovery requires maximum reservoir contact and hence the drilling of long near horizontal wells. Besides the challenging nature of well construction, other technologies adopted to improve recovery efficiency and operability includes subsea multiphase flow meters and sand control with inflow control devices.