Alan Petzet
OGJ Chief Editor-Exploration
HOUSTON, Oct. 22 -- A group led by Consolidated Contractors Energy Development (Oman) Ltd. (CCED) will shoot 3D seismic and use special test equipment to evaluate three heavy oil zones and a deeper light oil formation, all in late Neoproterozoic and early Paleozoic rocks, in eastern Oman.
Two wells 12 km apart have delineated the accumulations on the Saiwan East structure in the Saiwan subbasin on the eastern flank of the Ghaba salt basin 190 miles southwest of Muscat.
The 98,840-acre, 90-day 3D survey by China’s BGP Oil & Gas Services is to start within 2 weeks and cover the entire Saiwan East structure on Ghunaim Block 4, said partner Tethys Oil AB, Stockholm.
Former operator EnCana Corp. discovered heavy oil shows at Saiwan East-1 in 2005 in the Neoproterozoic Buah limestone and Middle Cambrian Miqrat and Amin sandstones (OGJ, June 9, 2003, p. 28). TD is 1,333 m.
The CCED group’s Saiwan East-2 well, 7.5 miles northeast of Saiwan East-1, went initially to 1,450 m and cut a gross heavy oil column of more than 400 m in the three heavy oil formations in May.
CCED then deepened to 2,300 m and at 1,600 m cut 30 m of oil-bearing late Neoproterozoic Khufai limestone that drillstem tested 280 b/d of 33° gravity oil on a 24/64-in. choke. No water appeared, and the gas-oil ratio is low.
Analysis of accumulated pressure data suggested skin damage from heavy drilling mud and implied that an undamaged Khufai could yield 900 b/d and possibly much more in a horizontal well.
A workover rig is needed to run specially designed test equipment to evaluate the three heavy oil zones. The companies have been analyzing cores taken across the most promising heavy oil intervals.
Tethys Managing Director Magnus Nordin said, “This 3D seismic survey is an important step in further understanding and proving up the resource base and evaluating the development potential of the Saiwan East discoveries.”
CCED and Tethys hold 50-50 interests in Afar Block 3 and Block 4.
Contact Alan Petzet at [email protected].
Photo from SABIC Limburg BV.
US Department of the Interior.
