Block 5B contains the southerly extension of the structural trend that is developed in the explored blocks to the northwest. A three well exploration drilling programme was completed in Q3 2008.

Block 5B is located in the prolific Muglad Basin adjacent to fields with production of over 300,000 barrels per day.

During 2007, activities have been delayed due to the slow implementation of the Comprehensive Peace Agreement which required the setting up of institutions to deal with the oil issue. This took place in 2007 when the National Petroleum Commission gave its endorsement of WNPOC and its right to conduct operations in Block 5B.

On the ground operations began in earnest in 2006, with some 440 km of seismic data being acquired, and continued into the first half of 2007 as a further 600 km of data were recorded. Parallel studies using this and older seismic led to the identification of a series of relatively shallow structural closures analogous to those successfully drilled in neighbouring Block 5A.

A three well drilling programme commenced on the block in Q1 2008 and was completed in Q3 2008.

Exploration
The drilling programme scheduled three exploratory wells, one located in a dry land location and two located in swamp conditions. The swamp wells required specially designed site preparation and drilling equipment was developed to allow operations in this difficult environment.

Drilling commenced on the west flank of the basin with the Nyal-1 well using a dry land rig in Q1 2008. The well found the target Aradeiba and Bentiu sandstones as forecasted, underlain by shales of the Abu Gabra formation, which constitutes the regional source rock. Minor gas shows were encountered from 1,475 metres to TD, but no oil shows were recorded.

A second well, Wan Machar-1, was completed in the swamp area using a barge mounted drilling rig complex. The well entered basement at 1,360 m. Minor gas shows were encountered but no oil shows were recorded. The well was plugged and abandoned as a dry hole.

The third well, Muny Deng-1 was located in the central area of the basin in the swamp area and was completed in Q3 2008. The well reached a total depth of 2,450 metres. Minor gas shows were encountered but no oil shows were recorded and the well was plugged and abandoned as a dry hole.

Further drilling in Block 5B has been postponed whilst the acquired well data and samples are analysed by the 5B partnership.