Geothermal Drilling Topics
January 5, 2009
Virginia's Fall Meeting Highlights Geothermal DrillingOn Oct. 10, more than 140 drillers and suppliers attending the Virginia Water Well Association Fall Meeting and Field Day were treated to a geothermal drilling and grouting demonstration. Also attending the demo were representatives of the Virginia Department of Health, the Department of Occupational and Professional Regulation, and the Southeast Rural Community Assistance Project.
The demo was held at Creason and Sons Well Service in Zuni, Va. John O’Dell, Well Water Solutions, and his crew provided the rig and drilled the 100-foot hole, and Scott Miller of Northern Virginia Drilling provided the grouting equipment and performed the grouting. They were joined by Mark Whittle, Baroid IDP, who conducted a class on the hows and whys of correctly grouting a geothermal well.
Afternoon classes on different aspects of geothermal installation of ground water source heat pumps were held at the Hilton Garden Inn, Suffolk, Va. Experienced geothermal drillers Cliff Bunn, Pinckney Well Drilling, David Kelly, Jones Well Drilling and Scott Miller conducted the classes. They were joined by Baroid’s Whittle.
Geothermal well drilling and installation are a natural diversification for well drillers who are interested in new sources of income. While there are some instructional courses that drillers entering this field should take, much of the equipment that is needed already is available in a well drilling contractor’s existing inventory. The biggest investment is the investment of time it takes to learn the techniques and formulas required for successful job.
More Than 190 Million Acres Planned for Geothermal PowerThe U.S. Department of the Interior plans to make more than 190 million acres of federal land in 12 western states available for geothermal energy development. Department of Interior’s Final Geothermal Programmatic Environmental Impact Statement (PEIS) identifies 118 million acres of public lands managed by the Bureau of Land Management and 79 million acres of National Forest System lands that could be opened to future geothermal leasing, potentially leading to 5,540 megawatts of new geothermal power capacity by 2015.
The PEIS excludes wilderness areas, wilderness study areas and national parks. It will amend 122 Bureau of Land Management land use plans to allow for geothermal development, while allowing the Forest Service the discretion of evaluating geothermal leasing, and considering whether to amend its land-use plans. The document also includes site-specific environmental analyses for 19 pending geothermal lease applications for seven sites in Alaska, California, Nevada, Oregon and Washington.
The plan will take effect via a Record of Decision, which will not be issued until the governors of the 12 states – Alaska, Arizona, California, Colorado, Idaho, Mon-tana, Nevada, New Mexico, Ore-gon, Utah, Washington and Wyo-ming – are able to review the document, and resolve any conflicts with state plans, programs or policies.
The Interior Department’s estimates of potential geothermal power production actually may be low, according to the United States Geological Survey (USGS). In late September 2007, the USGS released its first assessment of geothermal resources in more than 30 years. The study found that identified geothermal resources in the West could produce 9,057 megawatts of power, while another 30,033 megawatts of power could be generated from conventional geothermal resources that have not yet been discovered.
The use of Enhanced Geo-thermal Systems, which involves creating or expanding a geothermal resource through the high-pressure injection of a fluid, opens another 517,800 megawatts to potential development in the region.
Raft River Project Wins EGS GrantU.S. Geothermal Inc., a renewable energy company focused on the production of electricity from geothermal energy, recently won a grant from the U.S. Department of Energy (DOE). The DOE has chosen U.S. Geothermal’s Raft River site in Idaho to demonstrate the viability of Enhanced Geothermal Systems (EGS). The Raft River EGS program totals up to $9 million, with the DOE providing up to $6 million as part of the cost-sharing arrangement. U.S. Geothermal will provide in-kind contributions to the program through the use of several existing wells and technical data. The remaining team members are providing key contributions to the program. The program is designed to perform a monitored thermal stimulation of an existing injection well to improve permeability within the geologic horizon that hosts the Raft River geothermal reservoir.
U.S. Geothermal, the University of Utah, APEX Petroleum Engineering Services, and HiPoint Reservoir Imaging were selected as a team to negotiate with the DOE for work in 2009 to apply EGS stimulation techniques at Raft River.
The Raft River site was chosen for EGS development and has potential to access the typical range of production temperatures in EGS projects. Currently, U.S. Geothermal has a spare injection well and several monitoring wells that can be used for the demonstration. The program will study the in-place permeability of the geologic horizon that hosts the geothermal reservoir, and then will measure the impact of thermal fracturing using three different temperatures of fluid. Fracturing can occur when cold water is injected into a well where the hot rock exists. If targeted results are not achieved after thermal fracturing, hydraulic fracturing using pressurized fluids may be studied. In each case, the increase in permeability due to fracturing will be measured.
Successful completion of the DOE program at Raft River will provide key information on the future development of the Raft River resource to reduce the probability of drilling non-commercial production and injection wells. In addition, the data will provide new information on the successive changes in fracturing and permeability due to increasing differences between the temperatures of the in-place rock and the temperatures of the injected fluid.
The Raft River Unit One geothermal power plant has operated at 99.9 percent availability for the past 6 months. With the arrival of cooler temperatures, power generation is increasing, with current production in the range of 11.0 megawatts to 11.5 megawatts net. A reverse osmosis filtering unit is being installed, which is expected to significantly reduce chemical treatment costs in the cooling tower, and to reduce elevated levels of dissolved chloride from the cooling tower feed water. High chloride levels may be detrimental to the power plant condensing units. The project also is in discussions with several parties to look at the viability of cascade use of the geothermal energy, including year-round heating for greenhouse operations and other uses.