Laserfiche WebLink
Geothermal Rules <br />Effective Date: September 30, 2004 <br />9.4 Approved Grout and Placement- Only cement shall be used to grout a Type B <br />geothermal well, unless other grouts have been specifically approved by variance from <br />the State Engineer (see Rule 14). Cements and additives shall be selected to withstand <br />anticipated temperatures and corrosive fluids. A cement slurry shall be placed by <br />positive displacement in one continuous operation from the bottom of each interval or <br />stage. <br />9.4.1 Cement shall be placed immediately above the top of any potential <br />producing geothermal reservoir for a minimum interval of two hundred (200) feet or to <br />the surface if the depth of the reservoir is less than two hundred (200) feet. <br />9.4.2 A minimum of fifty (50) vertical feet of cement shall be placed opposite <br />each confining layer penetrated by the borehole (see Rule 4.2.7). <br />9.4.3 All cemented casing strings shall stand under pressure until the cement <br />reaches a compressive strength of five hundred (500) psi. The condition "under <br />pressure" will be complied with if a "float" or back pressure valve is used or if pressure <br />is otherwise held on the casing and no back flow is observed. <br />9.4.4 All casing and cements shall be tested prior to resuming well <br />construction operations. The test shall consist of applying a minimum pressure of five <br />hundred (500) psi to the casing and holding that pressure for thirty (30) minutes. Test <br />details shall be recorded and reported to the State Engineer. <br />9.5 Blowout Preventers - As soon as surface casing is set, a Type-B geothermal <br />well shall have blowout preventers or control heads installed. This equipment shall be <br />selected and designed to contain reasonably anticipated pressure and maintain control <br />of the well at all times, and shall be maintained in good working order. This requirement <br />for blowout preventers may be waived by variance from the State Engineer (see Rule <br />14) if the owner or operator can show from prior experience in the area that this <br />equipment is not necessary. <br />7ll��i[�>•�11►11►�11J►����_1�G7_\7��y�i7Zt7xi��a�7�1_\�:7�1�hlx��L�7�\�i�1���� <br />10.1 Well Construction - A geothermal reinjection well shall be classified as Type A <br />or Type B depending on the projected well depth and reservoir fluid temperature. The <br />respective construction and plugging standards for Type A and Type B geothermal wells <br />shall also apply to the construction and plugging of reinjection wells with the specific <br />additions and modifications provided in this Rule. <br />10.2 Mechanical Integrity Test - A fluid shall not be injected into a geothermal <br />reinjection well until a mechanical integrity test has been performed showing that the <br />injected fluid will be confined to the designated reservoir. At least ten (10) working days <br />23 <br />