Initial results from the Skipper appraisal well in the UK North Sea have shown oil "significantly" heavier than expected, but in sands with higher permeability than thought.
Operator and 100% owner Independent Oil and Gas says it will now review its development strategy for the field, which is in Block 9/21a in license P1609.
The firm said of the well results: "Although the oil is moving in the reservoir, the first sample results indicate that the oil is approximately 11° API and has a significantly higher viscosity than expected.
"These measurements do not align with our observations and therefore the remaining samples need to be reviewed and tested. Next steps will then be Reservoir modelling to consider potential development options. Determining commerciality may therefore take several months."
While the oil is heavier than expected, permeability through the reservoir sands is better than expected, at more than 10 Darcies.
The firm also thinks there's more oil in place than previously thought, due to the crest of the Skipper reservoir in the appraisal well being found to be 44ft shallower than prognosed. This has meant the firm's estimate of the most likely oil in place has increased from 136.5 MMbbl to 142.6 MMbbl.
Mark Routh, CEO of IOG commented: "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. We have observed that the oil moves in the reservoir and is mobile at surface at ambient conditions. The initial oil analysis results are incompatible with our observations, therefore we are now reviewing our strategy to establish the commerciality of Skipper. In addition, we have an increased oil in place, higher observed reservoir permeabilities and an increased reservoir height from the crest to the oil water contact."
The well was the firm's first as operator.
Subscribe
