Fifth, sixth wells at Yuzhno-Kirinskoye field reduce oil reserves, up gas reserves estimate
MOSCOW. Oct 24 (Interfax) - Drilling of the fifth and sixth exploration wells at the Yuzhno-Kirinskoye field in the Sea of Okhotsk in the 2014 field season has made it possible to increase the estimate of gas reserves and reduce the estimate of oil reserves, a source at Russian gas giant Gazprom told Interfax.
He confirmed the earlier estimate made by Gazprom department head Vsevolod Cherepanov, who put the increase at 100 billion cubic meters.
"A large part - up to 90% of the area - of the field is covered by accumulations of shallow gas, which distorts seismic data. As a result of drilling the fifth and sixth wells it was possible to clarify the picture about the positions of the upper boundaries of the productive horizon. It turned out to be 30-40 meters higher than previously thought. This will make it possible to easily add about 100 bcm," the source said.
At present, 637 bcm of gas reserves within the boundaries of the Yuzhno-Kirinskoye field have been booked with the State Reserves Commission.
It was reported earlier that drilling of the third and fourth wells at the field discovered 464 million tonnes of oil. However, only 6 million tonnes were provisionally booked.
The source said that the results from drilling the new wells make it possible to conclude that the oil reserves are lower. "At the same, the boundary of gas-water contact was raised. And while before the depth of the oil rim was estimated at 15 meters, now it has decreased to 4 meters," he said.
In the event of an associated occurrence of oil and gas, the oil is extracted first, since otherwise it will be lost. Extraction of oil requires the construction of more wells than gas extraction, which complicates the economics of a project.
The data of the latest recalculation of reserves will be submitted for review to the State Reserves Commission in February 2015, the source said.
