DOE Digest

DOE Announces 10 Microhole Drilling Awards

In late January DOE announced 10 project awards, involving $7.7 million of DOE funds and $6.8 million of industry partner funds.

Geoprober Drilling Inc. (Texas). This project calls for drilling three wells with an innovative composite coiled tubing (CT) drilling system. Goal is to confirm the capability to drill microhole exploration wells in water depths ranging up to 10,000 feet. Cost savings, projected at 59% over that for conventional wells, would come by using a smaller drilling vessel and by eliminating the need to deploy and retrieve a large riser.

Gas Technology Institute (Illinois). This project will test a next-generation microhole CT rig, MOXIE. The MOXIE experimental rig, fabricated by Coiled Tubing Solutions, was designed specifically for CT and microhole drilling to 5,000 ft. depths. First deployed for initial testing in a Kansas gas field last year, the rig was able to drill 280-400 ft. p/h.

Confluent Filtration Systems LLC (Texas). Researchers will seek to develop a revolutionary elastic-phase, self-expanding tubular technology called CFEX. The goal is to develop self-expanding well casings to any diameter.

Tempress Technologies (Washington). The goal is to develop a small, mechanically-assisted, high-pressure waterjet drilling tool. A downhole intensifier would boost the pressure that can be delivered by CT, maximizing drilling rates. That in turn would overcome the limited reliability, power, and torque of small-diameter drill motors.

CTES LP (Texas). Researchers will focus on improving the performance and reliability of microhole CT drilling bottomhole assemblies while reducing cost and complexity associated with drilling inclined/horizontal laterals greater than 2,000 ft. This would be accomplished by inducing vibration along the CT drill string, which would eliminate the need for a downhole drilling tractor to mitigate friction.

Technology International Inc. (Texas). This project entails developing and testing a downhole drive mechanism and a novel drill bit for drilling with CT. The high-power turbodrill will deliver efficient power at relatively high revolutions per minute and low bit weight. The more durable drill bit will employ high-temperature cutters that can drill hard and abrasive rock in 3½-inch boreholes.

Ultima Labs Inc. (Texas). This project is intended to combine existing technologies for

measurement-while-drilling (MWD) and logging-while-drilling  (LWD) into an integrated, inexpensive measurement system to facilitate low-cost CT drilling of small-diameter (3½ inch) wells at depths shallower than 5,000 feet. Two prototypes are to be delivered.

Baker Hughes Oilfield Operations Inc. (Texas). Researchers will seek to provide a wireless system to help steer drilling in a microbore. Plans call for developing a downhole bidirectional communication and power module and a surface CT communication link.

Gas Technology Institute (Illinois). This project entails designing, developing, and evaluating a counter-rotating motor drilling system for reducing costs associated with drilling wells targeting unconventional gas. By concentrating the weight on the drill bit in a smaller area and by addressing the limited torque on a CT drill string, this would increase CT drilling effectiveness.

Confluent Filtration Systems LLC (Texas). This project is designed to prove and develop a concept for a self-expanding, high-flow sand screen that could be constructed from a wide range of materials. Plans call for deploying the technology in a demonstration well.

View DOE Tech Line at www.netl.
doe.gov/publications/press/2005/
tl_microhole_selections.html.

Kansas Exploring Enhanced CBM from Landfill Gas (LFG)

Currently about 4.5 MMCFD of LFG is collected from the Johnson County, Kansas landfill. About half of the gas is methane and the other half is largely CO2. Now this gas is processed on the surface, resulting in about 3 MMCFD of pipeline quality gas. In a DOE-supported project, the Kansas Geological Survey and other partners are exploring the possibility of injecting untreated LFG into subsurface coalbeds. Since coal readily adsorbs CO₂, the coal would act as a natural processing agent, replacing the current surface processing equipment. Methane in the injected LFG would flow through the reservoir. Additional CBM gas would be produced from enhanced CBM.

Good idea, but will the concept work. In the project the local geology will be evaluated to determine structure, stratigraphy, depth and thickness of underlying coal seams. Coal samples will be obtained and their properties and reservoir conditions ascertained. Response of the samples to LFG gas will be determined. With this data, reservoir simulation will explore the economic potential. A listing of major U.S. landfills overlying coal-bearing strata will be developed.

View DOE project fact sheet at www.netl.doe.gov/publications/
factsheets/project/Proj324.pdf.

High-Pressure, Jet Assisted Drilling
Tested at RMOTC

In partnership with DOE's National Energy Technology Laboratory, Maurer Technology, Inc. of Houston developed an innovative drilling system that uses high-pressure drilling mud to drive a special mud motor and bit with small diameter drilling jets. High-pressure drilling mud in conjunction with small diameter jets results in very high velocity fluid streams. These streams cut kerfs in the rock at the bottom of the hole allowing the mechanical cutters to easily break the rock ledges, thereby significantly increasing drilling rates.

This system was field tested in a new well drilled in the Rocky Mountain Oilfield Testing Center in Wyoming last year at depths of approximately 4,300 to 5,200 feet. During the test, drilling pressures exceeded 7,500 psi at mud circulation rates of 200 gpm. The drilled interval included a variety of lithologies, ranging from clean, high porosity sandstone to limestone, as well as shale and siltstone.

Significant increases in drilling rate were evident over specific intervals, from two to seven times the conventional historical drilling rate. In some areas drilling rates had to be limited to allow proper cleaning of the hole. Difficulties were encountered with the high-pressure mud motor and nozzles in the drill bits. The mud motor's stator, which had aged during the project, failed downhole. The test was completed by drilling conventionally with the rig's rotary table, high-pressure drilling swivel, Kelly hose and mud pump. The RMOTC drilling crew also had to overcome some mechanical problems to operate the surface equipment used by the new high-pressure system. Overall, surprisingly few problems were encountered showing that high-pressure, jet-assisted drilling can be conducted using conventional commercially available equipment. Rig modifications were minimal and not cost-prohibitive. The most costly item was the high-pressure mud pump.

This field demonstration concluded DOE's involvement in this project. This technology is now available for commercialization by other companies. For more information on commercialization, contact Maurer Technology Inc. (John Cohen, email jcohen@noblecorp.
com).

Content excerpted from RMOTC's fall 2004 newsletter (www.rmotc.
com/Today/fall-news.pdf).