Privately-owned explorer Delonex Energy has made four oil discoveries in Chad’s frontier Termit basin and will begin drilling appraisal wells next year to also target a deeper, higher potential play.

“In the last year, we have drilled six exploration wells and have made four discoveries — these are exciting times,” said Lorna Blaisse, senior exploration geologist at Delonex, at the Africa E&P conference in London this week.

Blaisse did not reveal the discovery names or details about potential resources but speaking to Upstream on the sidelines of the conference — organised by PESGB and HGS — she said an appraisal campaign is set to start in early 2020.

China’s Great Wall Drilling drilled the six initial probes and would likely be well-placed for a future campaign.

“Phase two will focus on the appraisal... of existing Tertiary discoveries and unlock the basin’s true potential,” said Blaisse, adding that there are “hundreds of potential prospects still to pursue”.

The commerciality of Delonex’s crop of oil finds is unclear because Block H is a remote frontier play on the northern shores of Lake Chad.

The nearest export outlet is the Chad-Cameroon pipeline to the south, which transports declining volumes of crude from the Doba basin.

A possible export route could open in 2021 when a pipeline due to take oil from Niger’s Agadem basin to Benin’s coast is set for completion.

Block H abuts the Chad-Niger border and is immediately adjacent to the oil-rich blocks controlled by China National Petroleum Corporation and Savannah Petroleum in the Agadem basin.

Blaisse said Conoco drilled the first wells on Block H in the 1970s, making four non-commercial Cretaceous and Tertiary finds.

However, the US player pulled out due to the asset’s remote location while, at the same time, industry interest shifted south to the Doba basin.

Delonex gained control of Block H in late 2017 by acquiring Bermuda-registered United Hydrocarbon.

Since then, it has acquired 2700 square kilometres of 3D seismic data — another 800 square kilometre shoot is nearing completion — and more than 500 kilometres of 2D data.

Delonex has identified three oil plays in the block — two Cretaceous and one Tertiary.

The Tertiary reservoirs are fluvial, deltaic and lacustrine in nature, said Blaisse, with porosities over 25% and permeabilities up to six Darcies permeabilities “in very quartz-rich sands with minimal clays”.

She explained that studies suggest these geologically younger discoveries are the result of “leakage” from “a deeper and broader Cretaceous petroleum system” that has “both lighter and potentially more gassy accumulations than the Tertiary".

“The real intrigue for us,” said Blaisse, “is porosity preservation in over-pressured Cretaceous shales, a play which has the potential to open up huge new reserves in the basin and a broader variety of deeper traps.

“Much of our efforts... will focus on this deeper, unexplored potential. We believe a prize is out there and worth exploring.”

Delonex — headed by chief executive Rahul Dhir — has found mature Cretaceous source rocks right across the block and at many levels and with a total oil content of up to 20%.

Block H is one of three blocks Delonex holds with 100% stakes under a single production sharing contract.

The acreage is a 12-hour, 300-kilometre drive from N'Djamena via hard-top road, tracks and trails.

Weekly

Delonex makes four oil hits in Chad's Termit basin