Falkland Islands: Low permeability gas seen at Scotia

Falkland Oil & Gas Ltd. said its Scotia well in the South and East Falklands basin has proven a working hydrocarbon system in the mid-Cretaceous Fan play and demonstrated that Scotia is a viable stratigraphic trap.

The company plans to plug the Scotia well because reservoir quality was poor at this location. But the company found encouragement that better reservoir quality might exist elsewhere in Scotia because the seismic amplitude anomaly covers 350 sq km.

FOGL as group operator drilled the Scotia 31/12-01 well to 5,555 m. Well interests are FOGL 40%, Noble Energy Inc. 35%, and Edison International SPA 25%.

The well penetrated the mid-Cretaceous aged reservoir objective on prognosis. Strong gas shows (C1 to C51) were encountered while drilling the target section.

Interpretation of wireline log data indicates that the target interval 4,719-4,769 m comprises 50 m of hydrocarbon-bearing fine-grained sandstones and claystones. The wireline logs indicate that, at this location within Scotia, the sandstones form fairly poor quality reservoir even though some zones have as much as 20% porosity.

Other thin hydrocarbon bearing sandstones were encountered beneath the main target at 4,900-5,164 m. On subsequent evaluation using a wireline formation testing tool, the main interval did not flow hydrocarbons, indicating low permeability.

The FOGL group deepened the well below the main target in order to penetrate and sample Cretaceous aged source rocks. It obtained rock cuttings and sidewall core samples from several potential source rock intervals that are being sent for detailed analysis. The results should provide vital information on the quality and maturity of these source rocks and also provide a better understanding of the distribution of oil and gas in this part of the South and East Falklands basin.

The well data will be invaluable for calibrating the forthcoming 3D seismic program, which is to begin shortly, FOGL noted. The 3D seismic will be used to map sand fairways in the play and, when combined with detailed analysis from the Scotia well, should allow identification of better quality reservoir and differentiation between oil and gas prospects.

FOGL plans to fully evaluate the results of the Loligo and Scotia wells, focusing on three key themes:

• The evaluation of source rock potential and hydrocarbon migration in order to define potential oil bearing prospects.

• The identification of good quality reservoir within the Tertiary and Cretaceous prospects and plays.

• The potential commercialization of gas and associated liquids in the South and East Falklands basin.

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