One of the world's leading independent research centers for drilling and well technology is Rogaland Research in Stavanger. It has a staff of 250, including 50-60 Ph.Ds, and a wide range of facilities including the well-known Ullrigg Drilling and Well Center.
The institute is currently involved in a number of advanced well projects, covering such areas as drillstring dynamics, cuttings transport, hard rock drilling, near-bit sensor technology, rotary steering and window milling.
While some of the work takes the form of joint industry projects (JIPs), the institute's most comprehensive assignment at present is its part of the European Union's Thermie supported Advanced Wells program. For this two-year program which is due to end late this year, Rogaland Research is using one of the Ullrigg test wells for full-scale testing of a range of new technology.
Originally, it was to extend the U1 well from 1,070 meters to 2,000 meters, including a horizontal section, by drilling through the hard rock of the basement augengneiss. However, the rock proved so hard that it was impossible to achieve the rates of penetration required for the various tests which were planned, according to Rolv Rommetveit, the research manager for drilling and well technology. The project is now to be restructured with part of the testing transferred to Advanced Drilling in Montrose, Scotland.
A lot of work has been carried out on hammer drilling in hard rock, including testing hammers developed by the Swedish company G-Drill and Austria's SDS, giving the institute a good grasp on the necessity of directing all the vibration energy into crushing the rock without destroying the drillstring. "From this work, we have come to understand the physics involved," Rommetveit says. "Now, we are putting this knowledge into optimizing the hammering effect."
The institute has also developed an understanding of the frequency spectrum of the drillstring vibrations as a means of monitoring the condition of the drillstring, a capability which is of special importance to hammer drilling.
Alternative techniques such as putting jet pumps downhole to assist traditional tri-cone drilling are also being tested.
Another focus is on developing near-bit sensor technology, with the aim of providing more accurate information on drill bit position and behavior through real-time measurement close to the bit - in current configurations, MWD instruments can often be several tens of meters behind the bit.
The institute is also doing work on improved drilling data (IDD) under a JIP. The initial stage has led to the development of an IDD algorithm which has been incorporated in products now used by a number of service companies to provide improved logging data.
Another of Rogaland Research's assignments under the Thermie project is the testing of rotary steerable drilling systems which offer the much improved control over the placing of the bore which is necessary for long wells with complicated trajectories. The Baker Inteq rotary closed loop system which has now been launched as a commercial product underwent two tests at the Ullrigg center. The results in terms of quality of hole and penetration rate were very encouraging, according to Rommetveit.
The institute is also tackling the problems involved in the transport of cuttings out from the distant and often flat sections of long-reach wells. A small-scale flow loop is to be built and commissioned at the Ullrigg center in which the performance of drilling muds will be tested using gamma densitometers placed at a number of locations along the course.
Two muds will be qualified, one optimized in terms of cuttings transport properties, and the other in terms of environment-friendly properties. Testing is due to take place this autumn.
In a JIP funded by Shell and Agip and performed in conjunction with Transocean, Rogaland Research has also developed a method of window milling using abrasive fluid jets. This technology enables milling to be performed with very low side forces, in turn making it possible to use simple directional control equipment. Compared with equivalent mechanical tools, it requires a much smaller kick-off radius.
The method is suitable for through-tubing operations and enables side-tracks and lateral wells to be drilled more efficiently. It is due to be tested later this year, possibly at the Ullrigg center.
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