Tanzania: Nyuni-2 appraisal well to spud soon

By OGJ editors
HOUSTON, May 27 – The Nyuni-2 appraisal well is expected to spud around June 8, additional acreage has been negotiated north of the Nyuni block, and preparations are under way to connect the Kiliwani North discovery well to gas processing facilities on Songo Songo Island, said Bounty Oil & Gas NL, Sydney.

Nyuni-2 will be drilled from the same location on Nyuni Island as the Nyuni-1 well drilled by the Aminex PLC-operated joint venture in 2004. The planned well depth is expected to be 3,325 m below rotary table.

Nyuni-2 will appraise a location updip from the gas discovered in the Nyuni-1 discovery well in Albian-Aptian (late Lower Cretaceous age) sands as well as testing the underlying Neocomian (earliest Lower Cretaceous age) sands. It will be deviated 60° to the southeast to test a large four-way dip closed anticline.

Nyuni-1 established gas in the Albian-Aptian sands but did not test those sands at that location. Nyuni- 2 is designed to test those sands and the expected Neocomian sands nearer the anticlinal top above the gas-water contact. The large Nyuni structure has the potential to contain more than 1 tcf of recoverable gas.

The Neocomian sands expected at Nyuni-2 are the main reservoir sands at the Songo Songo gas-condensate field and at Kiliwani North gas field on Songo Songo Island 20 km south of Nyuni Island.

Success at Nyuni-2 will also lead to drilling of Fanjove North 10 km farther south from Songo Songo Island as part of the evaluation of the substantial prospect inventory on the Nyuni Block.

A new PSA has been negotiated with Tanzanian authorities that will include four contiguous blocks to the north of the existing PSA area. Finalization of the PSA is imminent.

A 3-km, 6-in. pipeline connecting the Kiliwani North wellhead to gas processing facilities on Songo-Songo Island is to be installed this year with first gas sales provisionally in early 2012 (OGJ Online, Apr. 15, 2011). Kiliwani North was discovered and tested in 2008, and consulting engineers estimated a mean 45 bcf of gas in place. Reservoir modeling indicates that 73-83% could be recovered.