Reserves lifted for East African gas field

May 2, 2006
Wells in Songo Songo gas field off eastern Tanzania showed a pressure decline of less than 2% in 2005, and analysis permitted a reserves increase despite no new drilling.

By OGJ editors
HOUSTON, May 5 -- Wells in Songo Songo gas field off eastern Tanzania showed a pressure decline of less than 2% in 2005, and analysis permitted a reserves increase despite no new drilling, said operator EastCoast Energy Corp., Tortola, British Virgin Islands.

Consulting engineers, relying on 2005 pressure and production data and field remapping, hiked proved and probable reserves 14% to 560 bcf. This amounted to a 41% rise in proved reserves to 241 bcf and a 25% hike in proved and probable reserves to 320 bcf.

Songo Songo's five wells produced 14.7 bcf in 2005, bringing cumulative production to 19.3 bcf since the start of commercial operation in 2004. Production peaked at 72.8 MMcfd on Aug. 6, 2005.

Gas demand is steadily increasing around Dar es Salaam, and spare deliverability is ample to meet contract volumes.

EastCoast Energy let a contract to Petrofac Engineering Ltd. to identify the most efficient means of boosting capacity to 120 MMcfd within 18 months. If a third processing train were installed, capacity would then be limited by the 232-km, 105-110 MMcfd pipeline from the field to Dar es Salaam.

EastCoast Energy plans to drill one or two wells on the northern part of the Songo Songo West prospect 2 km west of the gas field in 2007. The prospect is a tilted fault trap at the same Neocomian reservoir level as the main field.

A small semisubmersible or jack up would drill the wells in 20 m of water. Gas in place is estimated at a most likely 600 bcf.

The company is interpreting 328 km of seismic data shot on the Nyuni license under a farmout from Aminex PLC, London (OGJ Online, Oct. 18, 2005).