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GULF OF MEXICO

Rick Von Flatern
Houston

World's first production spar

Oryx Energy and CNG Producing has christened the world's first production spar. The FPS Neptune will be used as a production platform in the partners' Neptune project encompassing Gulf of Mexico Viosca Knoll Blocks 825, 826, 869, and 870. The Neptune field is about 90 miles south of Mobile, Ala. in about 1,930 ft of water.

Spars, vessels whose stability is derived from 90% submergence of its massive floating cylindrical hull, have been used for various deepwater projects in deep waters for 30 years and in the oil industry since the mid-1970s as floating oil storage tanks where pipeline systems did not exist or were uneconomical to install.

The Neptune, however, is the first spar to support a full offshore production facility and was chosen as an less expensive alternative to more conventional production facilities. The 705-ft long hull has a 72-ft diameter and weighs about 12,640 tons. The 3,600-ton topside will support production facilities, crew quarters, and workover equipment.

The production facilities are designed to handle 25,000 b/d of oil and 30 MMcfd of gas. The spar's mobility offers an advantage of singular importance to the Neptune project whose estimated 50-75 million boe reserves are in deposits scattered about the field around a salt dome. As reserves are depleted in one area of the field the production facilities will be floated to the next area to be produced.

Record-breaking Gulf lease sale

It is news to no one in the upstream oil and gas industry that the hottest offshore theater on the planet is the Gulf of Mexico. So it should be no surprise the final tally of high bids received by the US Department of Interior in its latest Minerals Management Service Gulf federal lease sale was a record breaker. A $511 million record to be exact, gleaned from 1,384 bids on 924 tracts, also records.

Texaco E&P, Chevron USA, and Zilkha Energy topped the winners list with 125 tracts awarded Texaco and 114 each to Chevron and Zilkha. Shell, the undisputed leader in Gulf of Mexico deepwater activity, was seventh on the list with 44 tracts. BP, BHP, Amoco, Vastar, Conoco, and Exxon made up the remaining top ten bidders who received cumulatively more than 700 of the 924 tracts awarded.

Well abandoned not in subsalt

Sometimes small announcements can lead to big misunderstandings. So it was last month when several trade publications, including this one, reported Enserch Exploration had failed to reach TD in a subsalt well in the Gulf of Mexico and had ceased operations there.

The report caused a measure of consternation among subsalt watchers who wondered if the Gulf of Mexico was going to offer new resistance to giving up its subsalt treasures now that 3D seismic had exposed them to the world. But such concerns, it turns out, are for naught. The well was not actually drilling through the salt but beside a dome. A still tricky but wholly different animal.

Original geology placed the wellbore about 2,000 ft from the dome's edge but Enserch deep water production manager, Jim Vernor, suspects the distance was closer to 700 ft. As a result, he feels, the proximity of the salt instigated such events as lost circulation and caving formations. But no one has offered a concrete reason for the difficulties with the well that actually penetrated 800 ft of pay but could not reenter the original borehole after tripping.

At any rate, Enserch has not ceased operations. It has moved to drill another development well to a different bottomhole location. And the subsalt play has displayed no new drilling complications though any driller with experience in long salt sections will testify to the dificulties of drilling and casing these massive, flowing structures.

Seismic on spec

Jebco Seismic and PGS Ocean Bottom Cable announced in mid-September the completion of Phase III of their Texas state waters 3D spec seismic survey. Acquired in July and August, Phase III covered more than 230 sq. miles offshore in the Galveston area of the Gulf and brings the total coverage in Texas state waters in 1995-1996 to 1,188 sq. miles, equivalent to 132 OCS blocks.

The program uses bottom cable technology to image in 3D the entire Miocene section, covering some of the most prolific gas-producing trends in the Gulf. The data set is the only 3D seismic data to tie together the Miocene producing trends offshore with new Oligocene Frio discoveries and prospects in the Texas bays and onshore trends.

Phase I of the program, the Matagorda and Brazos areas, are available for delivery. Phases II and III are being processed and will be delivered by the end of 1996.

New heavy lift system

A 220-ton topdeck was removed at the West Cameron 71-7 for Mobil using what the new Orleans-based marine contractor called "a new lifting method for large and heavy structures." Details from Bisso Marine were sketchy but a photo of its Versatruss system in operation display two barges, equipped with two booms and winches each, positioned in opposition so as to cradle the deck between them.

Copyright 1996 Offshore. All Rights Reserved.

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