What's happening offshore

November 1999 Vol. 220 No. 11  Offshore

Robert E. Snyder,  Editor

U.S. Gulf discoveries, other new technologies

Early October heralded the announcements of several U.S. Gulf of Mexico deepwater discoveries. Three operators announced discoveries in water depths between 2,000 and 4,000 ft.

Conoco, as 50% operator of the K2 prospect in Green Canyon Block 562, with partner Spirit Energy 76, drilled a discovery well in 3,900-ft water using Deepwater Drilling’s Deepwater Pathfinder drillship. The well is temporarily suspended pending appraisal plans. A deeper objective could also be tested. Pathfinder will mobilize to Mississippi Canyon Block 1002 to drill a well in 7,500-ft water. Conoco reportedly will earn an interest in the well through a farm-in with Chevron and Texaco.

Kerr McGee announced an oil discovery on its North Boomvang prospect, to a 9,478-ft TD on East Breaks 643, in 3,450-ft water, using R&B Falcon’s C. Kirk Rhein, Jr. semi. It offsets a 1997 discovery and is the first of several wells to be drilled in the greater Boomvang area, where the operator has five blocks leased, East Breaks 599, 642, 643, 688 and 732.

The rig will move 3 mi west to Block 642 to spud an 11,600-ft exploratory well on West Boomvang, then move on to East Boomvang. Kerr McGee operates Blocks 642, 643, 688 and 732 with 30% interest; partners are Reading & Bates Development Co. (50%) and Ocean Energy (20%). With Ocean Energy (50/50), Kerr McGee has also drilled the Nansen prospect, in East Breaks 601, 602 and 646, some 8 mi east of North Boomvang.

Murphy Oil says its discovery on the Medusa prospect in Mississippi Canyon 582 encountered 120 ft of net pay in 2,200-ft water. Diamond Offshore’s Ocean Concord semi drilled the well to 16,200 ft; an appraisal is planned. Murphy operates the lease with 60% for partners British Borneo (25%) and Callon Petroleum (15%).

AUVs for deep water. As reported by oil and marine analysts Douglas-Westwood Associates (DWA) of Canterbury, UK, a series of major discoveries in very-deep waters promises exciting opportunities, with which come problems of how to carry out the precision surveys for subsea installations. Conventionally done by towing sensors from survey ships, this becomes impractical in deeper waters due to the long cable lengths involved. Data quality suffers, and in harsh weather areas such as West of Shetlands, costs escalate sharply.

Autonomous Underwater Vehicles (AUVs) can help. As true pre-programmed robots, operating without cables to surface and using advanced navigation systems, they are designed to dive to the seabed, carry out high-precision seabed surveys, then return to their support ship with the data. Until recently, AUVs were restricted to prototypes in oceanographic research institutes and military establishments, but the potential they offer for costs savings in deep waters has opened up a number of potential applications.

A symposium by AUV-maker, Maridan, held recently in Copenhagen, attracted researchers and commercial organizations from around the world — a measure of the growing interest in AUVs.

DWA’s John Westwood sees great potential for the new technology. In a key-note speech at the symposium, he stated that AUVs also had the potential to greatly increase the efficiency of hydrographic survey operations. He envisages several AUVs running in parallel with a survey or research vessel, doubling or trebling its efficiency — or in some instances, replacing the vessel completely.

Leading survey company, Fugro, has just ordered an AUV, believing that, in deep water, their use could reduce survey time by 50%. But it is not only seabed surveying that is capturing industry attention. Several companies believe there is potential for "hybrid" AUVs, vehicles that could be launched from a floating production system, swim to a subsea wellhead, dock onto power and communications then carry out maintenance work under control of platform operators.

Shell estimates that AUVs, in both survey and work roles, could save them $30 million over 5 years. In addition, there is a demand for AUVs to gather oceanographic data and possibly survey submarine cable routes. "We expect the total civil subsea business to grow to more than $20 billion by 2003, Westwood said. "The potential for new cost effective technologies such as AUVs will be considerable." Douglas Westwood’s web site is: www.dw-1.com.

Subsea tree installations. As published in a two-page report in the September 27, Offshore International Newsletter, subsea tree installations are off last year’s peak. A technological achievement for the industry was reached last year when — for the first time ever — more than 200 subsea trees were installed worldwide. In 1993, over 100 trees were installed — in only five years, that number doubled. With drastic cuts in operator’s spending in 1999, fewer developments were sanctioned, lowering overall activity.

For 1999, a total 186 trees are projected for installation, a drop from 1998, but in the context of the last five years, the drop is minor.

Overall development activity has declined in the North Sea, an area of strong subsea activity. But activity picked up elsewhere, notably in the U.S. Gulf, Brazil, and West Africa. Common to those three regions is the increasing number of deepwater discoveries. In more development scenarios, subsea is proving to be the optimal development solution.

OIN notes that it took 32 years to reach 100 tree installations per year, from the first subsea completion in 1961, but only five years to go from 100 trees to 200 per year. As long as the world’s deepwater regions continue to yield promising discoveries, subsea completions will inevitably follow.

A table of 770 trees planned and under construction, excluding those already installed this year, lists trees by water depth and year, for 1999 through 2003. The largest number is for depths greater than 1,500 ft (48%), with the next largest number planned for 651 to 1,500 ft (24%). Then the water- depth plans diverge from the pattern, with the 301 to 450-ft range generating the third largest number of tree plans, 18% of the total. Summary reports by world area note several key projects underway or planned.

Copyright © 1999 World Oil
Copyright © 1999 Gulf Publishing Company