DEEPWATER DELINEATION ADVANCES IN GULF

Delineation is moving ahead in two promising deepwater areas of the Gulf of Mexico.

Oryx Energy Co., Dallas, plans to decide by the end of the year when to begin development of a Flex trend prospect in 1,500-2,500 ft of water on four Viosca Knoll blocks about 80 miles south of Mobile, Ala.

An exploratory well on one of the tracts, Viosca Knoll 826, last summer flowed a combined 11,356 b/d of oil and 9 MMcfd of gas from 385 ft of net pay in three zones, chalking up one of the gulf's largest flow rates.

Based on 11 successful wells on Blocks 825, 826, 869, and 870, Oryx estimates reserves of 80-150 million bbl of oil equivalent.

"We're confident of what's there," Oryx said. "It's strictly a question of when we'll begin development."

Later this year, Exxon Co. U.S.A. likely will drill a sixth Garden Banks area well in more than 2,200 ft of water to further delineate a field on Block 388.

The most recent delineation well on Block 388 flowed at sustained rates of 2,400 b/d of oil and 1.56 MMcfd of gas from the lower 100 ft of a 175 ft thick sand at 7,600 ft. The test excluded 65 ft of pay sand logged at 7,200 ft.

Operator Exxon's major partner on Block 388, Enserch Exploration Partners Ltd., Dallas, said reservoir characteristics of the untested portions appear more favorable than those of the tested zone.

VIOSCA KNOLL PROSPECT

Oryx's discovery well on Viosca Knoll Block 826 in summer 1989 logged 95 ft of net pay, and flowed 1,366 b/d of oil and 7 MMcfd of gas.

Oryx said additional drilling on Blocks 825 and 826 confirmed the size of the discovery. So far, two of three penetrations on Block 825 and six of seven on 826 have found multiple oil and gas pays in Miocene and Pliocene sands at 5,800-11,800 ft.

Oryx and Conoco Inc., which each own 50% interest in the play, paid $1.52 million for Blocks 869 and 870 last March at OCS Sale 131, after previous lessees allowed the leases to expire.

Three of four wells by past owners on Block 869 were successful. One well on Block 870 was a dry hole.

Oryx plans to collect more seismic data on Blocks 869 and 870, perhaps later this year, before wrapping up development plans. Oryx and Conoco earlier announced a Flex trend discovery on Mississippi Canyon Block 243, about 30 miles off Louisiana (OGJ, May 20, p. 38).

GARDEN BANKS 388

Exxon's fifth and most recent well on Garden Banks Block 388 was drilled directionally from the same surface location as the tract's discovery well.

But it found no significant pay where it penetrated the objective formation, 2,650 ft to the southwest on Garden Banks 387.

Exxon then sidetracked the hole to a point on Block 388, 2,165 ft southwest of the discovery well, where it logged 240 ft of net pay in two zones.

The Block 388 discovery well was drilled in first quarter 1989.

It found 250 ft of net oil pay in a single sandstone confirmed productive by logs, cores, and wireline tests (OGJ, Jan. 28, p. 112).

Exxon holds a 35.5% interest in the Garden Banks wells and Enserch 41.8%. Remaining interests are held by Placid Oil Co. 16.3%, Opubco Resources Inc. 3.8%, HI Production Co. Inc. 2%, and Penrod OCS Inc. 0.6%, all of Dallas.