To find out if laser drilling is feasible, the Gas Technology Institute, the U.S. Department of Energy's National Energy Technology Laboratory, and several project partners have joined in a new research effort that builds on a more basic study completed by the gas industry in 1999.
If drilling with lasers ultimately proves viable, it could be the most radical change in drilling technology in the last century.
It was at the turn of the 20th century when rotary drilling supplanted cable tool drilling as the petroleum industry's standard method for reaching oil and gas formations.
While major improvements have occurred since then, the basic mechanical drilling method has remained essentially the same.
Using lasers to bore a hole offers an entirely new approach. The novel drilling system would transfer light energy from lasers on the surface, down a borehole by a fiber optic bundle, to a series of lenses that would direct the laser light to the rock face.
Drilling 10 to 100 Times Faster:
The concept of laser drilling was largely confined to the imagination of petroleum engineers until significant advances in laser technology were made in the 1980s and 1990s as part of the military's missile defense research.
Now, researchers believe that state-of-the-art lasers have the potential to penetrate rock at 10 to 100 times faster than conventional boring technologies – a huge benefit in reducing the high costs of operating a drill rig.
Today, a typical land-based oil or gas well costs around $400,000 to drill, while costs for an offshore well average nearly $4.5 million.
But in some deeper or more difficult drilling terrains, costs can be much higher. Reducing the time a drill rig remains on site can lower costs and make previously uneconomic gas or oil deposits commercially attractive.
The earlier study by the Gas Research Institute showed that laser systems now can provide more than enough power to cut rock. Because the laser head does not contact the rock, there is no need to stop drilling to replace a mechanical bit.
Moreover, researchers believe that lasers have the ability to melt the rock in a way that creates a ceramic sheath in the wellbore, eliminating the expense of buying and setting steel well casing.
A laser system could also contain a variety of downhole sensors – including visual imaging systems – that could communicate with the surface through the fiber optic cabling.
The Energy Department selected the laser drilling project last year in a competition for new ideas to improve the way companies find and produce natural gas.
The proposal was originally submitted by the Chicago-based Gas Research Institute which subsequently combined with the Institute of Gas Technology, also of Chicago, to form the Gas Technology Institute.
"We are pleased to include the laser drilling study in our portfolio of advanced drilling technology development efforts. Currently we are investigating a wide range of new and in a few instances, novel drilling completion and stimulation technologies," said Bill Gwilliam, project manager at DOE's National Energy Technology Laboratory.
"We are convinced that breakthroughs in rate-of-penetration or extended drill bit life will contribute to our overall efforts to improve the economics of drilling for natural gas and oil in the United States."
Changing Conventional Wisdom:
While the lure of laser drilling has been its speed, one major drawback has been the large amounts of energy experts assumed would be required.
The 1997-99 Gas Research Institute study indicated, however, that conventional wisdom – much of it based on 20-year-old calculations – may have significantly overestimated the energy required to break, melt or vaporize rock.
One of the primary objectives of the new study will be to obtain much more precise measurements of the energy requirements needed to transmit light from surface lasers down a borehole with enough power to bore through rocks as much as 20,000 feet or more below the surface.
Another aspect of the study will be to determine if sending the laser light in sharp pulses, rather than as a continuous stream, could further increase the rate of rock penetration.
Pulsed laser have been used for better performance in cutting steel, for example. It may be likely that the pulsing action will flex and break the physical bonds between the rock grains, boosting the cutting effectiveness.
A third aspect of the new project will be to determine if lasers can be used in the presence of drilling fluids.
In most wells, thick fluids – called "drilling muds" – are injected into the borehole to wash out rock cuttings and keep water and other fluids from the underground formations from seeping into the well.
The technical challenge will be to determine whether too much laser energy is expended to vaporize and clear away the fluid where the drilling is occurring.
Later in the project, researchers could examine other ways to use lasers in oil and gas drilling. For example, after a well is drilled, perforations are created into the formation to start the flow of hydrocarbons. Part of the research effort will study ways lasers could be used to create these perforations.
The federal government will contribute about $500,000 to the 3-year feasibility study while the Gas Technology Institute and its partners will contribute another $214,000.
Joining the research effort will be the Colorado School of Mines, Argonne National Laboratory (Laser Applications Laboratory), Halliburton Energy Services, and Petroleos de Venezuela, SA.
Source: United States Energy Information Ad
© 2001 Mena Report (www.menareport.com)
