Algeria's Ain Tsila gas-condensate size grows

Well tests established a reservoir more than 22 km long at the Ain Tsila gas-condensate discovery on the Isarene permit in eastern Algeria’s Illizi basin, said Petroceltic International PLC.

By OGJ editors
HOUSTON, Jan. 12
-- Well tests established a reservoir more than 22 km long at the Ain Tsila gas-condensate discovery on the Isarene permit in eastern Algeria’s Illizi basin, said Petroceltic International PLC.

Tests at the AT-3 delineation well indicated that the gas column more than 80 m thick is in the same pressure regime as wells AT-1 and AT-2, “demonstrating that this gas-condensate discovery extends for a distance of over 22 km, from AT-1 to AT-3,” Petroceltic said.

Petroceltic and Algeria’s state owned Sonatrach could not frac the Ordovician reservoir at AT-3 because the pressures required exceeded the pressure rating of the wellhead equipment.

Local high in-situ stress caused by localized tectonic history is a known issue in other Illizi basin fields in Algeria. Petroceltic considers the pressure regime likely to be of limited extent rather than regionally extensive. The company filed a discovery declaration for Ain Tsila field.

Petroceltic suspended the well with a view to completing the fracture stimulation and testing as part of a future Ain Tsila appraisal campaign when wellhead equipment with a higher pressure rating can be deployed, possibly later in 2010, subject to government and partner approval.

Petroceltic said, “Data from the three wells drilled in the Ain Tsila discovery have demonstrated the presence of an extensive and probably continuous gas accumulation capable of flowing at rates exceeding 30 MMscfd following fracture stimulation.”

The company is drilling the INW-2 well on the Issaouane Northwest prospect in the northwest part of the block. The rig has logged two gas-bearing intervals in the primary Devonian F2 objective and is drilling in the secondary Ordovician reservoir objective. The Devonian F2 gas intervals will be tested after drilling is finished.

Petroceltic said it is “working to interpret and integrate the large volume of data from these discoveries, with a view to making an application to the Algerian authorities for an appraisal period extension to the production-sharing contract in the near future.”

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