December 1999 Vol. 220 No. 12  Drilling

Robert E. Snyder,  Editor

Slow turnaround for marine rigs

Putting together the Marine Drilling Rigs listing once a year is an interesting project, as the 12-month period between publications normally sees a lot of change in the worldwide offshore fleet of mobile drilling rigs. It wasn’t that way this year. In fact, the total number of rigs we show this year is 613, only seven less than in December 1998. The jackup fleet only declined by two rigs, to 362; the 165 semi-submersibles is the same number as last year. We list 77 drillships and barges, a drop of five; and submersibles stayed the same, at nine.

The problem behind these statistics is that a whole bunch of the rigs shown are stacked, a lot of them stacked cold. Offshore Data Services’ November Offshore Rig Locator lists 633 rigs in the same five categories noted above; of these, 470 are contracted, a 74% utilization. Of the 98 jackups not working, most of them were in the U.S. Gulf, the North Sea, West Africa and the Persian Gulf. The U.S. Gulf and the North Sea had 25 semis idle out of a total 84 units. The glamour remains in the deep water, where several newbuild drillships, and new and converted semis are headed.

Announcements of newbuildings / conversions were scarce this year, obviously. And with the controversy generated by some oil companies not honoring their contracts – which made building orders possible in the first place – it may take contractors a while to get their confidence back – even longer for anyone to order any rigs on spec.

In 1980–81, speculative new rig construction was "common." In fact, Global Marine bases its SCORE, Summary of Current Offshore Rig Economics, on present economics vs. those of 1980–81. SCOREs in the range of 20% to 23% this year mean we’re a long way from convincing a banker to fork over $250 million for a new rig. Global’s mid-October evaluation showed the worldwide September SCORE increasing a whole 0.3%, from August, to 23.1%.

That’s the right direction, but it’s not the climate for newbuilding announcements. I hope I’m still working on the marine rig listing when we run out of extra oil and gas, and rigs, at the same time – I think that’s possible.

Titanium drill pipe. Following years of extensive testing by Grant Prideco and RTI Energy Systems, Inc., titanium drill pipe has recently been used commercially for the first time on record. Torch Drilling Services LLC drilled the curved section of a short-radius horizontal well in Greeley County, Kansas, with a hybrid steel and titanium drillstring. The bottomhole assembly combined four joints of 2-7/8-in. titanium alloy upset pipe with a patented rotary steerable horizontal drilling system. The well path had a 58-ft radius of curvature to a target azimuth of 93°, and a very smooth planar borehole. The pipe was rotated at 50 to 80 rpm, while building angle.

Manufactured and supplied by Prideco and RTI, the titanium drill pipe was fitted with Prideco’s Fatigue Resistant steel tool joints specifically designed for high-stress, short-radius drilling applications.

Titanium weighs about half as much as steel, with twice its flexibility. These properties make it an excellent material for use in drilling difficult short-radius, extended-reach and ultra-deep wells, the developers say. A hybrid drillstring can significantly reduce drilling time and overall drilling costs. It can also be used in high-temperature, corrosive applications, and as a non-magnetic material for surveying.

Another downhole alloy. The British company Brush Wellman Ltd. says that its copper beryllium Alloy 25 is now being used for making drill collars. The principal advantage is flexibility. The material’s low modulus of elasticity allows the collar to bend and return to its original shape, despite relatively high deflection. And, the developer says, as the collars rotate, they deflect, with the surface continually alternating between tension and compression. The alloy’s fatigue resistance and high strength are important.

Another advantage claimed is that the alloy exhibits exceptional galling resistance, both when the copper-beryllium components are used together and when the C-B is used with components of other materials. This property can reduce thread galling / seizing at the collar joints, and can eliminate need for anti-seize compounds. The developer notes that the alloy is easier to machine, compared with stainless steel and other "exotic" alloys, and this may compensate for the "slightly higher price per kilogram" of the material.

Drilling with casing alliance. Tesco Corp. and Schlumberger Oilfield Services announced that they have entered into a worldwide Preferred Supplier and Alliance Agreement, whereby they will cooperate in providing specialized Casing Drilling (CD) services.

Tesco’s patented system combines retrievable / retractable Casing Drilling downhole assemblies and purpose-built tools which allow operators to simultaneously drill, case and evaluate oil and gas wells. Schlumberger provides an extensive range of drilling and production services, as well as project management services. The companies have also agreed, where appropriate, to work together in the continued improvement of the technology.

Cleaning with ice. Contrary to what one might think is possible or practical, the Indiana company Ice Cleaning Systems, Inc. has developed – and tested at the Rocky Mountain Oilfield Testing center (RMOTC) – a machine that generates ice crystals and shoots them through a nozzle to clean oil field equipment. The ICE 250 Cleaning Machine converts water into the small ice particles, then, using compressed air, the particles are forced through a hose to the nozzle.

Advantages? The developer says the solid particles clean efficiently, instantly melting, and partially evaporating, to a very minimal water volume. In the RMOTC tests, a dirty, oil-covered pump unit and an oily storage tank were cleaned down to the paint, which was not disturbed. And the procedures left little residue on the soil due to the lack of waste water. Developers say this is a major advantage when washing mud off rigs, as there is little excess water to contaminate or dilute the mud system.

Copyright © 1999 World Oil
Copyright © 1999 Gulf Publishing Company