Thunder booms over Thunder Hawk prospect
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Gulf of Mexico oil discovery uncovers 300 feet net pay in two high-quality zones
Ray Tyson Petroleum News Houston Correspondent
Owners of the closely watched Thunder Hawk prospect in the deepwater Gulf of Mexico say additional exploratory drilling has turned up about 300 feet of net oil pay capable of producing upward of 150 million barrels of equivalent.
Thunder Hawk is located in Mississippi Canyon on the northeast fringe of the BP-operated Thunder Horse field complex, the largest discovery in Gulf history at a reported 1.4 billion barrels of recoverable oil.
Thunder Hawk owners Dominion Exploration, Murphy Oil, Spinnaker Exploration and Pioneer Natural Resources went into their drilling venture believing they had a piece of Thunder Horse, 75 percent owned by BP and 25 percent by ExxonMobil.
Operator Dominion hinted at a significant discovery at Thunder Hawk in early May, reporting at least 100 feet of hydrocarbon bearing section in multiple thin sands of the middle Miocene horizon. It apparently took a sidetrack off the main well bore to establish the prospect’s true potential. Sidetrack results encouraging “We are very encouraged by the results of the sidetrack well and are assessing delineation drilling options,” Duane Radtke, Dominion’s chief executive officer, said June 28.
The sidetrack well, on Mississippi Canyon block 734, was drilled 150 miles southeast of New Orleans, La., in a water depth of 5,724 feet. The well reached a total measured depth of 24,831 feet and a true vertical depth of 23,101 feet. Dominion said the well would be temporarily abandoned.
The approximately 300 feet of net oil pay encountered by the sidetrack was situated “in two high-quality reservoir zones,” the company said.
“Our current estimate of reserves based on the two penetrations is from 50 to 150 million barrels of oil equivalent,” Radtke said.
Dominion holds a 25 percent working interest in Thunder Hawk. Murphy has 37.5 percent stake, followed by Spinnaker with a 25 percent interest and Pioneer with a 12.5 percent position. Both fields in Boarshead basin Both Thunder Hawk and Thunder Horse, in the Boarshead basin, are overlain by so-called “allocthonous” salt bodies, which tend to distort seismic readings and make imaging difficult. The eight-block Thunder Horse complex is scheduled to launch first production next year at 250,000 barrels of oil per day and 200 million cubic feet of natural gas per day.
However, because of the region’s complex geology and reservoir imaging challenges, no one is certain of Thunder Horse’s true potential.
Some analysts believe the play could hold upward of 7 billion barrels of recoverable reserves, although 3 billion barrels is often cited as the likely mean.
Most of the federal leases within a 15-mile radius of Thunder Horse have been scooped up by various companies over the past five years, demonstrating the region’s strong attraction to explorers. Other players in the area include Shell, ChevronTexaco, ConocoPhillips, Marathon Oil and Anadarko Petroleum.
However, the Thunder Hawk partners were able to acquire their prospect in the 2000 Central Gulf of Lease Sale 175 for an uncontested $2.1 million. Ironically, Thunder Horse partners ExxonMobil and BP chose not to bid on the block.
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