Kosmos Energy Ltd., Dallas, reported that the Tortue-1 exploration well, drilled on Block C-8 offshore Mauritania, intersected 351 ft of net hydrocarbon pay in the primary Lower Cenomanian objective, based on preliminary analysis of drilling results and intermediate logging to a depth of 4,630 m.
Intended to test the Tortue West prospect forming part of the Greater Tortue complex, the well was drilled by the Atwood Achiever drillship in 2,700 m of water 285 km southwest of Nouakchott.
A single gas pool was encountered in the primary Lower Cenomanian, which comprises three “excellent quality” multi-Darcy reservoirs totaling 288 ft in thickness over a gross hydrocarbon bearing interval of 528 ft, Kosmos says. A fourth, 62-ft zone was penetrated within the secondary Upper Cenomanian target over a gross hydrocarbon bearing interval of 492 ft.
Kosmos describes it as a “significant, play-opening gas discovery.” Tortue-1 is now drilling to the planned total depth of 5,250 m.
An appraisal program is being planned to delineate the Tortue West discovery, Kosmos says. In addition, the Marsouin-1 exploration well in the central part of Block C-8 is expected to spud in the third quarter.
An exploration program is also being formulated to test the other prospects in the Greater Tortue complex, which extends into the St. Louis Offshore Profond block in Senegal, including the Tortue East and Tortue North prospects. In support of this program, a 3D seismic survey acquired over our Senegal blocks in 2014 is being processed and interpreted.
Kosmos owns 90% interest in the Tortue prospect, along with Societe Mauritanienne Des Hydrocarbures et de Patrimoine Minier (SMHPM) with 10%. Since 2012 Kosmos has held rights to conduct exploration in the C-8, C-12, and C-13 contract areas under production sharing contracts with the Government of Mauritania (OGJ Online, Apr. 10, 2012).
The blocks are contiguous, range in water depth between 1,000-3,000 m, and have combined acreage of 27,000 sq km.
This year Chevron Mauritania Exploration Ltd. acquired 30% nonoperated interest in the C-8, C-12, and C-13 contract areas under PSCs (OGJ Online, Feb. 4, 2015). Chevron has an option to elect to participate at 30% interest in the Tortue prospect, subject to Chevron paying a disproportionate share of their costs related to the Tortue-1 well.
Ivory Coast-Ghana boundary dispute
Meanwhile, the Special Chamber of the International Tribunal of the Law of the Sea (ITLOS) rejected a request by Ivory Coast that Ghana suspend all ongoing exploration and development operations in the area subject to a maritime boundary dispute in which the Tweneboa, Enyenra, and Ntomme (TEN) project is situated until ITLOS gives its decision on the dispute, expected in late 2017 (OGJ Online, May 31, 2013).
ITLOS ordered Ghana to suspend new drilling in the disputed area. Kosmos says it’s not a party to the arbitration process and will now await a decision by the government of Ghana on how it will implement the provisional measures order.
“However, we fully expect TEN development activities will continue as planned,” Kosmos says.
The project is now more than 55% complete with all of the wells expected to be online at production launch already drilled. The start of production is expected in second-half 2016.
“We are pleased the TEN project can continue, and we remain confident that the boundary, as it has been drawn and respected by both Ghana and [Ivory Coast] for over four decades based on the principle of equidistance, is both factually and legally correct, and will ultimately be sustained in this arbitration,” commented Inglis, adding that it’s “also important to note that the provisional measures granted do not affect the Jubilee field (OGJ Online, July 3, 2013).”