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Geothermal Rules <br />Effective Date: September 30, 2004 <br />pressure for a minimum of thirty (30) minutes, and/or to the pipe manufacturer's testing <br />specifications, whichever is greater. Pressures shall not decline by more than ten (10) <br />percent during the test. <br />8.7 All geoexchange systems shall be equipped with a pressure shutdown switch. <br />8.8 Limits of a Type A Geothermal Well Exceeded - All well construction <br />operations shall be suspended and the State Engineer shall be notified immediately <br />when geothermal fluid temperature greater than two hundred and twelve (212) degrees <br />Fahrenheit is encountered during the construction of a Type A geothermal well. No <br />further construction shall be allowed unless a permit for a Type B geothermal well has <br />been approved by the State Engineer and the well complies with the construction <br />standards for a Type B well. <br />•11I i Ii Ill III i� •' • <br />9.1 Well Construction - The construction standards of the Water Well Construction <br />Rules, 2 CCR 402-2, shall apply to the construction of a Type B geothermal well, with <br />the additions and modifications stated in this Rule. However, a Type B geothermal well <br />need not be constructed by or under the supervision of a contractor licensed by the <br />State Board of Examiners of Water Well Construction and Pump Installation <br />Contractors. <br />9.2 Surface Casing - Steel surface casing must be set at least twenty-five (25) feet <br />into impervious and competent bedrock to insure a solid anchor for blowout prevention <br />equipment. Sufficient cement shall be used to seal the entire length of the surface <br />casing. <br />9.2.1 In areas where subsurface formations and pressures are not known, <br />surface casing shall not be set less than ten (10) percent of the proposed total depth of <br />the well or a minimum of fifty (50) feet, whichever is greater. <br />9.2.2 In areas where subsurface conditions have been established by prior <br />well construction, the surface casing shall be set at a depth to protect all known and <br />potential aquifers and to prevent blowouts or uncontrolled flows, but in no instance shall <br />the depth of steel surface casing be less than fifty (50) feet. <br />9.3 Protection or Production Casing - The setting depths and cementing intervals <br />for each proposed well shall be designed and selected to prevent fluids from migrating <br />through the annulus between the casing and the borehole. All well casings shall be <br />selected and designed to protect against failure due to internal pressures, collapse due <br />to external pressures, or corrosion. <br />22 <br />