Africa Oil and its partner in block 9 Marathon have announced the start of drilling of the Sala-2 appraisal well following the discovery of gas in the Sala -1 well.
The sala-2 appraisal well according to a statement from the partners is designed to test the updip extent of this main reservoir sand.Sala-2 will particularly focis on gas tested at low rates at the lower interval of Sala-1.
Sala-1 drilled a large 80 square kilometer anticlinal feature along the northern basin bounding fault in the Cretaceous Anza graben and encountered several sandstone intervals which had oil and gas shows.
An upper gas bearing interval tested dry gas at a maximum rate of 6 mmcf/d from a 25 meter net pay interval while the lower interval tested gas at low rates of dry gas from a 50m potential net pay interval.
Earlier this month the operator Africa Oil said that the company, its partner (Marathon Oil) and the government were still discussing the probability of an appraisal well that would offer a clear picture of gas reserves on the block.
“Plans being discussed include an up-dip location to confirm the areal extent of the gas zones tested where the full net sand interval can be intersected above the gas-water contact. The partnership is also considering a down-dip appraisal location to test an on-lapping stratigraphic wedge on the flanks of the structure which is of the same age as the zones in the nearby Ndovu-1 well which had oil and gas shows,” Africa Oil said in a statement.
Africa Oil also said it was considering drilling an appraisal well on the crest of the large Bogal structure to confirm the large potential gas discovery which is estimated to have closure over an area of up to 200 square kilometers.
The gross best estimate of prospective resources for Bogal are 1.8 trillion cubic feet of gas based on a third-party independent resource assessment. Africa Oil currently has two optional slots on the Great Wall drilling rig used to drill the Sala-1 well that are available for this appraisal program.
The Sala-1 discovery was particularly important as it significantly derisked the Anza basin.