AN Australian company Invictus Energy Limited has confirmed the potential of oil in Muzarabani, Cabora Bassa Basin in Mashonaland Central Province 25 years after Mobil carried similar studies in the area and left.
Discovery of oil in that region could fast-track Government efforts at turning around the economy.
The Cabora Bassa Project encompasses the Mzarabani Prospect, a potentially trillion-cubic-feet-plus conventional gas-condensate asset which is the largest, undrilled seismically defined structure onshore Africa.
In a statement on Monday, Invictus Energy said: “Preliminary gravity data reprocessing confirms shallow basement trend associated with Mzarabani anticline and identifies further leads Invictus Energy Limited (“Invictus” or “the Company”), is pleased to announce that the ongoing basin modelling study (the “Basin Model”) and geochemical studies confirm the oil potential of the Cahora Bassa Basin.”
The statement quoted Invictus Energy Managing Director Scott Macmillan saying: “The results of our ongoing technical work are extremely encouraging and is enhancing our understanding of the potential of our acreage in the Cabora Bassa Basin. The basin modelling and source rock characterisation is one of the key pieces of work that significantly derisks the charge timing and availability to the Mzarabani Prospect and the wider basin as well. In addition, new processing techniques applied to the raw datasets that were not available 25 years ago are beginning to show additional structural detail in the basin that was not previously possible as indicated by the preliminary gravity processing results.”
“Our technical work is continuing on this exciting project and we look forward to updating the market on our progress in due course as our work programme delivers results.”
It said conclusions from previous source rock characterisation and basin modelling studies undertaken by Mobil more than 25 years ago “have been superseded with new geological understanding derived from updated industry classification of source rock types and basin modelling methods”.
Invictus Energy further noted that the deep lacustrine (lake) source rock type in the Cabora Bassa Basin was not widely regarded 25 years ago as having significant oil generating potential.
It noted that recent multi-billion barrel oil discoveries in onshore African rift basins like the Albertine Graben in Uganda and the Lokichar Basin in Kenya were derived from deep lacustrine source rocks contained in the basins.
These significant oil discoveries in these basins and elsewhere which are derived from lacustrine source rocks has resulted in the reclassification of their potential as rich oil and wet-gas generating source rocks, it said.
The company said it is in the process of acquiring additional outcrop source rock samples over the basin wide area to further enhance the geochemical dataset.
“The Basin Model further demonstrates a reduction in the key risk previously identified by Mobil relating to the timing of hydrocarbon charge and trap formation. The previous basin modelling work by Mobil concluded that the Upper Angwa source rock may have generated and expelled hydrocarbons prior to the formation of the trap (Mzarabani anticline / 4-way dip closure)
“The new Basin Model concludes that the source rock within the primary target of the Mzarabani Prospect, the Upper Angwa Alternations Member, is within the oil and wet gas window present day on the flanks of the basin, and has undergone active hydrocarbon generation post trap formation from the source kitchen within the Mzarabani fetch area,” said the company.
It added that the Basin Model had also implemented updated understanding of the thermal regime and burial depth history which is a key control of the hydrocarbon phase generation (oil or gas) for this source rock type.
“Previous Mobil work assumed the strict and now outdated ‘McKenzie Model’, which results in an overestimation of the regional thermal gradient. This therefore led to higher modelled maturities and the conclusion that the hydrocarbon phase was more likely to be gas than oil.
However, the current Basin Model demonstrates that the Mzarabani Prospect may lie within both the light oil generation window (at the crest of the structure) and the wet-gas generation window (on the flanks of the structure) due to size of the structure and significant vertical relief.”