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  4. US Potential

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- [Voiceover] Figure one here was, that's a heat flow map of the United States. It was constructed by Blackwell and Richards in 2006, and Blackwell and Richards used extensive thermal data sets and other heat flow data sets, one which included a 1974 AAPG study using bottom hole temperatures. And this data allowed for heat flow to be determined in the geographic range within the United States. And as we can see, we have highest areas of heat flow throughout the western U.S., down in Texas and Louisiana, we have high heat flow areas and some selective areas in the eastern states. Looking at figure two, this is a map showing bottom hole temperatures using the AAPG data and others, this again was produced by Blackwell in 2006 and others. We see Wyoming, Texas, and Louisiana are all areas where we have temperature ranges between 76 and 150 degrees Centigrade. Southern Texas, we have a cluster of bottom hole temperatures indicating temperatures of 150 degrees to 260 degrees Centigrade, and it's important to note that these temperatures are comparable to those used in developing enhanced geothermal systems, and these wells may be more than suitable for exploiting geothermal energy in this method. Blackwell and others also produced high-grade EGS area temperature maps at certain depths, and at four kilometers here, we have again, over 100 degrees Centigrade and areas of over 150 degrees Centigrade, at four kilometers depth. If we go to six kilometers depth, we see significantly higher temperatures over 200 degrees Centigrade and possible modification to these wells could, obviously, reduce costs for reaching these depths instead of upright financing or up costs for EGS drilling. Now, some of the positive aspects of EGS development is that there's a wide potential and a huge energy potential for the United States. It can be, like I said, potentially developed by utilizing abandoned wells within depleted hydrocarbon reservoirs. It can be built upon, and it obviously is built upon oil and gas production methods, for example drilling and hydrofracturing. It's reliable and it produces very low emissions. Possible negative aspects of EGS is the availability of water in the western states and in arid regions. Also, as we can see from a study in the Basil Field in Switzerland, there may be an increased seismic risk potential as water is injected to depths, and like I said from two slides ago from themap, drilling depths could limit development, as heat is obtained greater than 5,000 depths on average in the western states. In eastern U.S., we obviously would expect to find larger drilling depths, which would increase costs. Some examples of EGS development in the United States. We can see the Coso geothermal project, located un the Coso volcanic field, about 100 miles north of Los Angeles. We have temperatures ranging from 200 to 238 degrees at less than two kilometers of depth. EGS is considered an enhanced geothermal system as it was refractured. The reservoirs were extended through hydrofraction. Initial, traditional production began in 1987 and over 100 wells have been drilled. It currently produces about 270 megawatts of energy and is currently operated by Caithness Energy. Other EGS development is located in the Geysers in California, located about 20 miles north of San Francisco. It's the world's largest dry stream field, and it was one of the primary sites selected for testing EGS technology. Its traditional peak production was in 1987, and EGS installations began in 2001. The injection of municipal waste water is part of the specific aspects of this EGS system because it collects municipal waste waters from outlying communities and the injection depths are about 7,000 to 10,000 feet, and these injection rates are centered around 11 million gallons per day. Currently, this total field produces approximately 900 megawatts of energy. Looking internationally at the developing EGS projects, we can look at the Cooper Basin in Australia. The Cooper Basin was explored for oil and it lies above a granitic basement. It has a very large potential of five to 10 gigawatts of energy. It is currently in development, in terms of enhanced geothermal systems development. An injection well was installed in 2003, October 2003, and it was drilled to a depth of about 4400 meters. And it was placed in proximity to a known historic oil exploration well, and it was built upon that. The first well was drilled next to the historic oil well and it found bottom hole temperatures of around 250 degrees Centigrade. And very high pressures, 5,000 psi above hydrostatic. Second injection well, Habenero-2, was drilled and it was to intersect fractures stimulated from Habenero-1. Approximately a four kilometer-squared reservoir was created.