Exploration: Orca has mapped and evaluated the Songo Songo West (SSW) prospect adjacent to the Songo Songo Field. Timing for the drilling of Songo Songo West has been stretched out until unresolved financial issues in Tanzania can be satisfactorily addressed.The prospect is located in water depths of approximately 18 – 35 meters and will require a jack-up drilling rig. It is approximately 2.5 kilometres west of the main field and is mapped on seismic as having closure on an elongate north-south oriented tilted fault block trap. As with the Songo Songo main field, two reservoirs are envisaged to be present within the SSW prospect – the Neocomian and the Cenomanian, although the primary exploration potential lies within the Neocomian interval. SSW lies entirely within the Company’s Discovery Blocks.
McDaniel & Associates conducted an independent assessment of natural gas resources in the SSW prospect in September 2008. The prospect is interpreted by McDaniel to be low risk with a 52% chance of success in the Neocomian and 35% in the Cenomanian. McDaniel assessed the P50, unrisked recoverable resources in SSW at 450 Bcf and the mean, unrisked recoverable resources at 551 Bcf. Management’s unrisked mean GIIP for the Songo Songo West prospect of 810 Bcf compares with the McDaniel combined Neocomian and Cenomanian unrisked mean GIIP of 740 Bcf.Songo Songo West represents a major potential source of additional new reserves in the Songo Songo area.
Production: Orca is the operator of the Songo Songo gas wells and gas processing plant on behalf of Songas, the owner of the production and transportation infrastructure.
The processing infrastructure includes two gas processing trains, each originally rated at 35 MMcfd (70 MMcfd total). To meet increased demand the throughput capacity was raised (in Q2 2011) when Orca signed a re-rating agreement with Tanesco and Songas to operate the gas processing plant at levels up to 110 MMcfd. However the pipeline itself and the pressure requirements at the Ubungo power plant currently restrict the infrastructure capacity to a maximum of 102 MMcfd.
Processed gas is transported from Songo Songo to Dar es Salaam in a high pressure 25-kilometer 12” offshore pipeline and a 207-kilometer 16” onshore pipeline operated by Songas.
To establish significant additional deliverability Orca completed the drilling of the new SS-11 development well at mid-2012 . The well has now been tied in and is available for production. The total cost of the SS-11 well is estimated to be US$38. This well is the first significant part Orca’s announced Tanzania expansion program to be able to increase production capacity to 200 MMcfd.
Plans are awaiting approval for Songas to expand the processing infrastructure by installing two new gas processing transmission trains on Songo Songo Island that could ultimately handle 200 MMcfd. With additional compression the capacity of the high pressure marine pipeline can then be raised from 102 MMcfd to 144 MMcfd. Then once the onshore pipeline is twinned, the system will be able to operate at up to 200 MMcfd.