Sea Lion hailed as giant Falklands oil find

By OGJ editors
HOUSTON, June 7 -- Rockhopper Exploration PLC said its Sea Lion discovery in the North Falkland basin in the South Atlantic has located an estimated 170-242 million bbl of recoverable medium gravity crude oil as “the first contingent oil resource in the Falklands.”

The company said it will test the 14/10-2 discovery well at its earliest opportunity during the current campaign. Total depth is 2,744 m.

“The well penetrated what the company believes is a regional seal between 2,250 m and 2,374 m subsea. Based on log analysis, wellsite evaluation of shows and samples, sidewall cores and wireline formation testing, it appears that all sands encountered beneath this regional seal at the Sea Lion location are charged with oil and no oil-water contacts were encountered,” Rockhopper said. The oil is 26.4-29.2° gravity.

Management said it believes the well has opened a new play fairway on the PL032 and PL033 licenses (see map, OGJ, May 17, 2010, p. 37).

“The top oil sand in the Sea Lion well was encountered at 2,374 m subsea, and the base of the lowest oil sand was encountered at 2,591 m subsea. The total vertical oil column is 217 m, with total net pay of 53 m in seven identified pay zones, the thickest of which is approximately 30 m gross,” Rockhopper said.

“Pressure data suggest the possibility of two separate oil columns, although this will have to be confirmed by a full well test. The main Sea Lion fan has a net pay interval of 34.5 m. Additional underlying sands have net pay totaling approximately 18 m. Approximately 16 m of this lower pay appears to relate to a Sea Lion lower fan, which had been previously recognized, but not included as a primary prospect. A further 2 m of deeper pay has also been encountered.”

“The oil-down-to level of 2,591 m subsea is 116 m beneath the lowest mapped point of the Sea Lion fan. The entire Sea Lion fan has an areal extent of over 45 sq km and there are strong seismic indications of thicker reservoir packages elsewhere in the fan,” Rockhopper said. “The oil-down-to level is significantly lower than the lowest point of the Sea Lion main fan.”

RPS Energy Pty. Ltd. listed 717 million bbl as a best estimate of stock-tank oil initially in place in the Sea Lion main fan with a range of 232-1,493 million bbl. It listed 146 million bbl as a best estimate of STOIIP in the Sea Lion lower fan with a range of 53-370 million bbl.

RPS listed 215 million bbl as a best estimate of recoverable contingent resource in the main fan with a range of 35-597 million bbl and 44 million bbl as a best estimate with a range of 8-148 million bbl for the lower fan.

Rockhopper said the Sea Lion estimates are subject to change following a more detailed technical review.

Examination of sidewall core samples confirms extensive good oil staining and good reservoir characteristics. Logging data are indicative of good quality reservoir, with average porosity of 19% and good permeability, Rockhopper said.

Rockhopper holds a 100% interest in the PL023, PL024, PL032, and PL033 licenses that total 3,800 sq km. It has also taken farmouts from operator Desire Petroleum PLC and holds 7.5% working interest in PL003 and PL004.

Meanwhile, BHP Billiton and partner Falkland Oil & Gas Ltd. have spudded their first exploration well, Toroa F61/5-1, off the Falkland Islands (OGJ Online, June 4, 2010).