Western Gas, Operator of Exploration Permit WA-519-P, is scheduled to drill the Sasanof-1 exploration well offshore Western Australia in the first quarter of 2022. The Sasanof Prospect is on trend and updip of the Mentorc Gas and Condensate Field and nearby the Giant Gas Fields of Scarborough and Io-Jansz in the Carnarvon Basin.
The Sasanof Prospect covers an area of 505 km2 and is estimated to contain 24 Tcf gas and 1.1 Billion bbls condensate (P50 GIIP1), with a geological chance of success of 35 per cent based on Western Gas estimates. Sasanof-1 will be Western Gas’ first well drilled from its extensive exploration portfolio surrounding the existing Equus Gas Project that contains a discovered resource of 2 Tcf and 42 MMbbl (2C Gaffney Cline2). The Equus Gas Project has a historic exploration drilling success rate of 88 per cent, with 15 discoveries from 17 wells.
Through the licensing and reprocessing of 3D seismic in the area, Western Gas has developed an exploration portfolio of over 20 leads and prospects from Triassic, Jurassic and Cretaceous in age. These opportunities range from low risk Direct Hydrocarbon Indicator (DHI) supported Triassic prospects similar to many fields in the region to large play opening Jurassic Syn-rift leads.
Will Barker, Executive Director said Sasanof-1 marks an important milestone for Western Gas’ exploration activities, being the first exploration well to be drilled since the discovery of the Equus Gas Fields.
“The Mentorc discovery in 2010 was a play opener for the Barrow Delta Front. It proved that the area contains world-class reservoirs with low CO2 and high-quality gas and condensate.”
The Sasanof Prospect is a large, seismic amplitude supported, structural-stratigraphic trap in the high-quality reservoir sands at the top of the Cretaceous top Lower Barrow Group formation on the Barrow Delta within the Exmouth Plateau. Sasanof is supported by DHIs with strong amplitudes defining the prospect and the reservoir is anticipated to be of high quality and effectively sealed at the top of the Lower Barrow Group.
Mr Barker said building on the Mentorc discovery and armed with the latest 3D data and advanced geophysical techniques, Western Gas has been able to demonstrate that Sasanof has the potential to be another Giant Gas discovery.
“Drilling success at Sasanof has the potential to change the dynamics of the greater North West Shelf,” he said.
Western Gas has secured the Valaris MS-1 mobile offshore drilling unit (MODU) to drill the well. The MS-1 is a Generation-6 Deepwater semisubmersible MODU currently operating in waters off the Carnarvon Basin,Western Australia. Drilling will commence at the earliest in mid-February 2022, subject to approvals, with an estimated total campaign duration of 25 days.
An Environment Plan for the exploration well has been submitted to the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) for assessment. The Environment Plan covers well design and drilling operations, installation and testing of well safety equipment, and well evaluation activities.
Sasanof-1 will be a vertical well and drilled to a total depth of approximately 2500 m in 1070 m of water. In the success case, the well will be comprehensively evaluated and fluid samples will be recovered to allow for the certification of resource volumes. Upon completion of well evaluation activities, the well will be permanently plugged and abandoned with the wellhead removed. The drilling campaign is estimated to cost $US20 million. Western Gas is finalising an agreement with a listed company to farm in to Sasanof-1 to support the funding of the well.
Upon success, a discovery of the estimated size of Sasanof will provide multiple gas supply opportunities, including domestic gas, LNG backfill and expansion, and new value-adding gas-led industries.
Sasanof Prospect Technical Information has been provided as a supplement to this announcement. Click to view