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St. Malo gets bigger Another 400 feet of net oil pay uncovered, weighing Walker Ridge options Ray Tyson Petroleum News Houston Correspondent
St. Malo, already an impressive deepwater find by Gulf of Mexico standards, is looking more like a major oil discovery as the owners examine results from a key appraisal well and review their development options.
Last October’s announced discovery at Walker Ridge block 678 encountered more than 450 feet of net oil pay, ranking St. Malo among the U.S. Gulf’s more promising deepwater oil prospects but raising questions about the field’s reach and true potential.
The owners answered at least one of those questions in early July with an appraisal well that recently penetrated more than 400 feet of net oil pay more than a mile east and below the initial discovery.
“The appraisal well results … indicate the field’s potential hydrocarbon resources are greater than previously suggested by the discovery well,” St. Malo operator Unocal said July 1.
Unocal said the evaluation process would now focus on field productivity, the need for further appraisal drilling and viability of various development options, “with the current objective of establishing commerciality in 2005.”
Unocal holds a 28.7 percent interest in St. Malo. Devon holds a 22.5 percent interest, Petrobras a 25 percent interest, ChevronTexaco a 12.5 percent interest, EnCana a 6.25 percent interest, ExxonMobil a 3.75 percent interest and Eni a 1.25 percent interest. Appraisal well in 7,000-plus feet of water The St. Malo appraisal well, in 7,032 feet of water and drilled to a total depth of 28,903 feet, actually re-entered and deepened the Dana Point dry hole drilled in 2001 that stopped roughly 2,000 feet shy of the prize.
Deepening the existing well cost the owners just $31 million, about $25 million less than drilling a new one.
Aside from expanding the discovery itself, the St. Malo appraisal well provided further evidence of the enormous potential and extent of the deeper Eocene and Paleocene horizons of the lower Tertiary trend.
“This successful appraisal well reinforces our enthusiasm for the St. Malo discovery and the potential of the entire lower Tertiary trend,” said John Richels, president of St. Malo partner Devon Energy.
Those deeper horizons already have yielded announced discoveries at neighboring Cascade and Chinook, within 30 miles of St. Malo. FPSO being considered St. Malo owners have indicated that any development plan at St. Malo could include discoveries at Cascade and another nearby discovery, Sturgis. A Devon representative said at May’s Offshore Technology Conference in Houston, Texas, that one option being considered for the area is a so-called FPSO, or floating production, storage and offloading facility.
FPSOs, useful where pipelines and other infrastructure are sparse or non-existent, are typically used for isolated fields around the globe but have yet to make their debut in the Gulf. Oil is generally transported ashore via marine tankers.
Upon completion of the St. Malo appraisal well, the Discoverer Spirit drillship is scheduled to test the Sardinia prospect on Keathley Canyon block 681, also a lower Tertiary target. And Devon is currently drilling another high-potential lower Tertiary exploration target called Jack, on Walker Ridge block 759.
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