BHP is planning to undertake riserless light well intervention (LWI) activities in relation to the Crosby-3H1 well located in production licence area WA-42-L in Commonwealth waters, which forms part of the Pyrenees Development. The Pyrenees Development recovers crude production from fields located in both WA-42-L and neighbouring WA-43-L using the Pyrenees Venture floating production, storage and offtake facility (FPSO).
The closest landfall to the Crosby-3H1 well is the Cape Range Peninsula, Exmouth, approximately 27 km to the southeast. The water depth in the operational area for the activity is approximately 200 m, with the Crosby-3H1 well located in 197 m. The distance of the operational area to key marine and coastal features is:
+ Commonwealth/State waters boundary – 17 km south-southeast;
+ Ningaloo Marine Park boundary – 13 km south;
+ Muiron Islands Marine Management Area – 20 km southeast; and
+ North West Cape – 27 km southeast.
Crosby-3H1 is a dual-lateral well originally drilled in 2010 with a second lateral drilled in November 2015. Crosby-3H1 requires artificial gas lift operation in order to produce from the well. To reduce excessive water production from the dual-lateral well, BHP proposes to isolate the water producing lower lateral to enable the remaining upper lateral to increase the oil production performance. The common term given to this technique applied to solve excessive unwanted water production is water shut-off. The LWI activities will be undertaken using a LWI vessel to establish on the well and conduct the intervention activities utilising riserless subsea intervention equipment and wireline technology.
The LWI activities will be short in duration, with the LWI vessel expected to be on location in the production licence area for up to 14 days, contingent on weather conditions and unforeseen circumstances. The LWI activities will take place 24 hours a day, 7 days a week. To account for potential delays or schedule changes, the environmental assessment encompasses the petroleum activity occurring at any time between 01 September 2020 and 31 January 2021, pending vessel and equipment availability.