Tullow finds Butiaba's thickest pay in Uganda

By OGJ editors
HOUSTON, July 28 -- An appraisal well in the Butiaba region of Uganda Block 1 encountered more than 40 m of net oil-bearing reservoir, the thickest oil pay encountered in the Butiaba sector, said Tullow Oil PLC.

The Ngiri-2 appraisal well found the 40 m of net pay in two zones in a 131-m gross oil-bearing interval. The well went to 892 m 1.7 km north of the Ngiri-1 discovery well on the Warthog prospect (see map, OGJ, Feb. 16, 2009, p. 34).

Tullow Oil noted that after 32 successes in 33 wells the Lake Albert Rift basin still delivers from the upside potential. The company said it has discovered more than 950 million bbl of oil and estimates the yet-to-find prospective resource at 1.5 billion bbl.

Logging and sampling operations at Ngiri-2 confirmed the presence of movable oil in both zones. The lower zone encountered an oil-water contact, and pressure data from the upper zone indicate the possibility of a deeper contact than expected.

Reservoir quality is excellent, akin to Kasamene field in Block 2, where a production rate of 3,500 b/d of oil was achieved during testing in 2009.

Ngiri-2 is the first of a multiwell appraisal program planned to further evaluate the extent and recovery potential of Ngiri field. Tullow plans to drill the Ngiri-3 and Ngiri-4 downdip appraisal wells designed to establish oil- water contacts and reservoir distribution.

Tullow suspended Ngiri-2 and is moving the rig to the Mpyo-1 wildcat location. Tullow operates its 100% interests in Blocks 1, 2, and 3A.

Tullow said, “This continued success supports our planning for the accelerated basinwide development with our future new partners Total and China National Offshore Oil Corp.”