Rick Wilkinson
OGJ Correspondent
Carnarvon Petroleum Ltd., Perth, has announced its plans for redevelopment of Buffalo oil field in the Timor Sea. The field now lies completely within the jurisdiction of East Timor following the signing of the Maritime Boundary Treaty with Australia earlier this year (OGJ Online, Feb. 27, 2018).
Carnarvon has already established an office in Dili and appointed a specialist Timor Leste advisor.
The company is currently canvassing suppliers for the drilling of the Buffalo-10 production well, which will be positioned to confirm attic oil in the structure as well as drill deeper into the previously developed part of the field that was producing about 4,000 b/d of oil when the field was shut in.
Recent seismic work supports the existence of the attic containing an undeveloped oil column of up to 60 m in thickness, up-dip of the field’s previously highest perforated interval.
Buffalo-10 will be the first of three production wells connected to a leased floating production, storage, and offloading vessel. The well will be drilled using a jack up rig in 25 m of water.
Production will be via a small 50Te wellhead platform topsides supported on a three-leg steel jacket. Three conductors will be drilled and grouted through the jacket legs and also act as foundation piles. There will be one spare slot available.
Capital expenditure is estimated to be less than $150 million, a figure that includes the three production wells. Total operations expenditure for the 5-year project is expected to be $400-500 million.
The three wells are expected to produce an estimated 31 million bbl of oil over a 5-year period.
Buffalo field was discovered in 1996 by BHP Petroleum about 12 km from Woodside group’s Laminaria oil field in 30 m of water with reserves then estimated to be in excess of 20 million bbl of light 53° API oil. It was brought on stream at about 12,000 b/d by BHP and joint venture partner Canadian Occidental Petroleum in 1999 via a wellhead platform tied into a FPSO moored 2½ km away in 255 m of water.
Nexen Petroleum took over the field in 2002 and continued production for another 2 years. By 2004 the field had produced 20 million bbl and was still flowing at 4,000 b/d when Nexen decided to cease production and instigated abandonment of the facilities.
Carnarvon acquired the surrounding permit WA-523-P in 2016 with the aim of using modern seismic processing techniques to better interpret the top reservoir of the three known oil accumulations in the block.