Independent Oil & Gas PLC (IOG) says a sample from its first appraisal well on the Skipper oil discovery of the northern North Sea indicates 11° gravity oil, “a significantly higher viscosity than expected.”
Skipper lies on Block 9/21a in license P1609, where IOG is sole owner and operator. In July and August, the firm drilled the well to a TVD of 5,578 ft and retrieved oil samples as it moved toward a development plan (OGJ Online, Aug. 22, 2016).
The firm says the measurements do not align with its observations and therefore the remaining samples need to be reviewed and tested. The next steps will then be reservoir modeling to consider potential development options. Determining commerciality may therefore take several months.
“The analysis of the oil retrieved from the appraisal well indicates that Skipper is a heavy oil discovery with similar gravity to other nearby heavy oil fields,” explained Mark Routh, IOG chief executive officer. “We have observed that the oil moves in the reservoir and is mobile at surface at ambient conditions.”
IOG notes the crest of the Skipper reservoir in the appraisal well was found to be 44 ft shallower than prognosed. As a result, the firm’s estimate of the most likely oil in place has increased to 142.6 million bbl from 136.5 million bbl in the 2013 competent persons report.
The quality of the sands, although not cored, suggested permeabilities of more than 10 darcies, which is better than previously assumed, the firm says.