The National Energy Technology Laboratory (NETL) is launching a major research and development initiative to create a small, fast, inexpensive and environmentally friendly rig for drilling 5000 feet boreholes to investigate potential oil and gas reservoirs. Initial feasibility and proof of concept studies have indicated that wellbore diameters of 2-3/8 to 1-3/4 inches (microholes) using coiled tubing drill rigs are possible. Field tests have demonstrated that small diameter holes can be drilled to depths of 700 feet using a small-footprint coiled tubing unit. Positive results from these field demonstrations along with modeling and laboratory tests indicate that drilling microholes to depths of 5,000 feet can be achieved with relatively modest modification of existing drilling equipment and coiled tubing technology. Road Map for a 5000-FT Microborehole

Microdrilling technology along with micro-instrumentation could provide potentially low-cost wells for exploration, long-term reservoir monitoring, and production. Reduction in materials, labor, and support equipment all serve to reduce drilling costs by as much as one-fifth the cost of drilling a conventional well. Volumes of drilling fluids and cuttings can also be reduced by approximately one-fifth, reducing disposal costs. Smaller footprints and lower disposal volumes lower the environmental impact of drilling activities making microhole drilling applicable in environmentally sensitive areas.

To assist in the planning process for NETL's Microhole Technology Initiative, an Inital Market Evaluation Report, documenting the state of the coiled tubing market and trends in drilling costs in the U.S. was prepared. A meeting was held of petroleum industry operators, service companies and equipment suppliers on April 29-30, 2003 to provide input to the planning process and assist in developing a roadmap for the technology development. Topics discussed at the meeting included: the potential uses and benefits of microhole technologies; capabilities needed in terms of temperature, depth, pressure, etc; enabling technologies needed for microhole systems; technological barriers to developing critical technologies; target drilling and completion costs that would make this technology attractive; and barriers to market penetration.