Gulfsands Petroleum reported Tuesday that results from its Khurbet East 102 Triassic appraisal well fit with initial estimates that volumes from the Butmah Formation amount to 19.2 million barrels of oil equivalent.
The firm – which has interests in the Middle East, Europe and the US, and whose shares are quoted on London’s Alternative Investment Market – also updated its investors on operations, saying that both the Khurbet East and Yousefieh oil fields continued to perform “extremely well” last year.
Gulfsands said the Khurbet East appraisal well results are “generally consistent with pre-drill expectation”, with hydrocarbon columns and reservoir characteristics interpreted as broadly confirming the company’s initial estimate.
KHE-102 encountered the Butmah Formation at a depth of 9,340 feet (2,847 meters) Measured Depth below rotary table, 8,010 feet (2,442 meters) True Vertical Depth below mean sea level. Three consecutive core sections each of 39 feet (12 meters) length were cut, with hydrocarbons shows from core sections and drill cuttings indicating the presence of both gas and oil within the formation.
An open-hole flow test showed that the Butmah Formation flowed wet gas at an average rate of 10.7 million cubic feet of gas per day over a five-hour period on a 32/64-inch choke, with an associated hydrocarbon liquid rate of 524 barrels per day of 58 degree API condensate. No formation water was produced. The testing operation was terminated prematurely for safety reasons following the failure of a down-hole packer supporting the well test completion string.
Interpretation of results from the flow test, electrical wireline log data and reservoir pressure data recovered over the Butmah Formation, confirms the presence of an oil reservoir with an overlying gas cap as seen in the original oil discovery at KHE-101. The KHE-102 production test initially flowed wet gas with a condensate yield of 49 barrels per million cubic feet, but as a result of the failure of the packer, it was not possible to subsequently flow oil from the oil leg.
The well was subsequently deepened to the Triassic Kurrachine Dolomite Formation, but in spite of extensive shows of light oil being present on drill cuttings and a single core section recovered, the Kurrachine Dolomite failed to flow oil during an open-hole test, even following acidification of the reservoir interval. Gulfsands said that this was probably as a result of the absence of natural fractures within the low-permeability reservoir interval at this location.
Gulfsands added that both its Khurbet East and Yousefieh oil fields performed “extremely well” in 2011, with four new production wells drilled that raised oil production to a level in excess of 24,000 barrels of oil per day by August (prior to the impact of European Union sanctions). Later in the year, static pressure surveys conducted on shut-in wells further confirmed the presence of a strong aquifer in both fields, with positive implications for reserves bookings, said the firm.