Forging New Frontiers: Kosmos Scores Again Offshore Mauritania

Kosmos Energy has made a play-extending gas discovery offshore Mauritania, bolstering its confidence in the underexplored basin and laying the foundation for an LNG project.

But the search is still on for oil.

The Atlantic Margin-focused E&P said its Marsouin-1 exploration well in Block C offshore Mauritania hit at least 70 m (230 ft) of net gas pay in Upper and Lower Cenomanian intervals comprised of excellent quality reservoir sands. Drilled in nearly 2,400 m of water, the well is located about 60 km north of the Tortue-1 gas discovery that opened the basin, Kosmos said.

Kosmos’ discovery comes as many of its peers cut back on exploration, especially in frontier areas, as the downturn marked by lower commodity prices and profits lingers. But the company’s quest could unlock a new petroleum system to help meet the world’s growing energy needs. The company, which reported on Nov. 2 that year-to-date capex was about $515 million, spent about $130 million to drill the Marsouin-1 well.

“Well-to-seismic calibration has significantly de-risked the discovered resource base, as well as future prospects in the basin,” Kosmos CEO Andrew Inglis said. “The well results have validated our charge model and given us growing confidence in our ability to predict the oil and gas potential of this emerging, large-scale petroleum system. We have a disciplined exploration and appraisal program planned to further unlock the basin.”

The discovery marks the second successful find offshore the Mauritania/Senegal area for the Dallas-based company. Based on preliminary estimates, the discovery has commercial potential given it is thought to hold an estimated 5 trillion cubic feet of gross resources with substantial upside.

“Kosmos is executing a disciplined exploration and appraisal program to fully unlock the Mauritania and Senegal basin. We found a large gas resource and continue our search for oil,” Inglis said on a conference call on Nov. 12.

He added that seismic amplitude and AVO attributes accurately predicted reservoir and hydrocarbon pay in both the Marsouin-1 and Tortue-1. Kosmos believes geologic data gathered from the two wells will lead it to oil in the basin.

“The key message here is the outboard Cretaceous petroleum system offshore Mauritania and Senegal is highly underexplored and has very significant gas and oil potential,” said Brian Maxted, chief exploration officer for Kosmos.

He explained that significance of the find, saying well information and interpretation of seismic data show source kitchens for three known hydrocarbon charge systems based on industry and proprietary well information along with fluid and rock samples. These include the gas-mature Barremian source and the oil-mature Albian and Cenomanian-Turonian sources, all of which are in the Cretaceous.

Pointing to seismic data Maxted highlighted the many stratigraphic trapping fairways, indicating many prospects.

Moving forward, Kosmos plans to drill up to six more exploration and appraisal wells—half of which will be drilled by the end of the first half of 2016—over the next 18 months. The company aims to confirm the 15 Tcf resource base at the Tortue discovery, now known as the Ahmeyim, solidifying its commerciality.

“We believe that given the resource density the development of Ahmeyim will form the foundation of a world-class LNG project with the Marsouin anticline providing additional high-quality resources to exploit,” Inglis said. “Our second objective is to fully unlock the remainder of the basin to a strategic and targeted search for oil.”

Kosmos believes that its best chances of finding oil is farther north in Mauritania and to the south in Senegal, the same source rock that charges the Ahmeyim and Marsium reservoirs could be present and contain oil.

The 2015-2016 agenda includes acquire additional 3-D seismic data to define prospects on other structural trends. The main objective is to target prospects in anticlinal fairways in Mauritania and Senegal in hopes of hitting oil.

As for drilling, the program includes two wells in southern Senegal and one well in northern Mauritania in the next two years, Kosmos said.

In the meantime, the Atwood Achiever drillship—which drilled the Marsouin-1—is moving on to the Ahmeyim-2 site in the southern part of Block C-8 offshore Mauritania. Kosmos said the drillship will drill the top-hole section of the well before sailing to Senegal to spud Guembeul-1. The well will be the first in a series of wells to delineate the Greater Tortue area before year-end.

“We are clearly drilling a frontier basin here, so there are unknowns,” Inglis said. “We learned a lot from Tortue-1. …. With the combination of both wells we have greater confidence in that model.”

Velda Addison can be reached at vaddison@hartenergy.com.