Rockhopper Exploration plc , the North Falkland Basin oil and gas exploration company, reports the following update from the recent flow test on well 14/10-2: “Sea Lion 1”.
The test was carried out over four perforated intervals totalling 77m between 2,403m and 2,566m (below drill-floor). Upon retrieving the perforating guns, a gun misfire was apparent and only the top two intervals were found to have been perforated, meaning the lower two intervals did not contribute to the flow.
After perforation, a small amount of oil was produced into the tubing to clean the perforations and enable downhole oil sampling. The well was then shut in for approximately 2 hours to determine the initial reservoir pressure. The final recorded pressure was 3,385 psia at gauge depth (2,344.6m below drill-floor) and was still building.
The well was then opened to flow through the three and a half inch test string, initially on a 24/64th choke, opened to a 64/64th choke during the flow period and reduced to 44/64th towards the end of the flow period to allow samples to be taken. The well was flowed for approximately 18 hours without incident and for sustained periods of over 2,000 barrels per day (“BOPD”) with a maximum rate of 2,304 BOPD. The final flowing wellhead pressure was approximately 120 psia. A wax dissolver chemical was injected at the subsea test valve to mitigate the appearance of wax.
Rockhopper believes that the flow rate was inhibited by incomplete perforation, waxing of the tubing string above 800 metres, increased viscosity of the oil as it cooled in the upper part of the test string and a lack of specialist equipment. As such, the Company estimates that the well could have flowed at approximately 4,000 BOPD without these constraints. Rockhopper also believes that, with a more optimal well location and horizontal well completions, significantly higher flow rates could be achieved from future production wells.
Source: RockhopperExploration,September 24, 2010,