Or. Admin. Code § 632-020-0095 - Casing Requirements

(1) The permittee of any geothermal well or prospect well must properly case the well with adequate grade casing and cement the casing where necessary to provide adequate anchor for blowout preventers. Casing design must take into account stress imposed by the maximum expected temperature and the physical effects of produced fluids and gases on casing durability. Surface casing for any well with a proposed depth of more than 500 feet must be set at a depth of at least ten percent of the proposed total depth of the well, or at least 25 feet into consolidated, competent rock, whichever is deeper, unless otherwise approved by the department. In areas with no nearby drilling history, surface casing must be set to a minimum of 300 feet into consolidated, competent rock or confining clay layer, unless otherwise approved by the department.

(2) The permittee of a geothermal or prospect well must prevent commingling of fluids. The permittee of a geothermal or prospect well that penetrates a fresh water aquifer must set casing or tubing through this formation and cement such casing or tubing from bottom to top unless the department approves a different program.

(3) Casing and casing seals used for prospect wells, where the temperature of groundwater does not exceed 250°F, must comply with the general standards for the construction and maintenance of water wells set by the State Water Resources Department.

(4) Each fluid-bearing zone above the producing horizon in a geothermal resources well must be cased and sealed off to prevent the migration of formation fluids to other areas. Such casing and sealing off must be completed and tested using the methods and means prescribed by the department.

(5) Cements used in cementing casing and sealing formations must be of a grade and type best suited for expected reservoir temperature, formation water chemistry and bonding properties. Cements acceptable for use in high-temperature holes include Modified Type A or G, Alumina Silica Flour, Phosphate Bonded Glass, or other equivalent high-temperature design cement.

Notes

Or. Admin. Code § 632-020-0095

GMI 4, f. 7-20-72, ef. 8-1-72; GMI 4-1980, f. & ef. 10-2-80; GMI 1-1983, f. & ef. 9-30-83; GMI 2-1995, f. & cert. ef. 3-10-95; DGMI 1-2010, f. & cert. ef. 6-22-10; DGMI 3-2013, f. & cert. ef. 3-21-13

Stat. Auth.: ORS 522

Stats. Implemented: ORS 522.305