In early May 2018, industry sources suggested that Malian company Petroma is in talks with a European IOC to farm out a stake in Block 25, Taoudeni Basin, southern Mali. The block covers 42,013 sq km and includes the western part of the Nara Trough. It was awarded to Petroma in 2007 and is set to expire in April 2019. Petrroma currently holds a 100% interest in the block.  In 2016, the Bourakebougou development permit was carved out of Block 25, it contains the Bourakebougou hydrogen gas field on which Petroma has started a pilot production. Further appraisal drilling started in November 2017.  In 2012, Petroma was planning to acquire 900km of regional 2D seismic data and 150 sq km of 3D seismic data over Block 25. The block lies near the southern boundary of the Taoudeni Basin and rocks in the area comprise Neoproterozoic sedimentary rocks and intrusive rocks. The basement belongs to the Leo Shield of the Western African Craton.  Petroma completed the acquisition of gravity data covering the Bourakebougou discovery and covering the F1 and F2 stratigraphic wells in Block 25, in December 2011. Data indicate that the basement lies at a depth of in between 1,600 and 1,800m in the Bourakebougou area and in between 3,600 and 4,000m at the Djidieni area.  Â In 2009, Petroma drilled two stratigraphic wells, F1 and F2, to a depth of 2,000m. The wells were drilled in the north-western part of Block 25 and confirmed the presence of a sedimentary basin. Petroma believes that sandstones reservoirs and source rocks (pelite and limestone with dissolution cavities) have been encountered in both wells. The stratigraphic succession penetrated by the two wells has been subdivided by Petroma into three intervals. The lower interval belongs to the Souroukoto Group (So) and the upper interval to the Bakoye Group (Ba). These two intervals are separated by an interval of transition strata. Core data indicate a shallow marine, subtidal to supratidal depositional environment.  In April 2009, the company completed an aeromagnetic and gravimetric survey over Block 17 and Block 25. Acquisition covered an area of some 67,200 sq km. Geological interpretation of the data suggest that the basement lies at a depth of in between 3,600 and 5,200m in the northern part of the studied area.
Mali, Block 25