West Virginia Code of State Rules › Agency 35 - Oil And Gas › Title 35 - LEGISLATIVE RULE DIVISION OF ENVIRONMENTAL PROTECTION OFFICE OF OIL AND GAS › Series 35-03 - Coalbed Methane Wells Rule › Section 35-3-5 - Casing Requirements - Coalbed Methane Wells

Current through Register Vol. XLI, No. 28, July 12, 2024
5.1. Fresh Water Casing - For each coalbed methane well, the operator shall run and permanently cement a string of casing through the fresh water bearing strata. The fresh water protective casing shall extend at least thirty (30) feet below the deepest fresh water horizon (that being the deepest horizon which will replenish itself and from which fresh water or usable water for household, domestic, industrial, agricultural, or public use may be economically and feasibly recovered) and shall have cement circulated in the annular space outside the casing. The volume of cement needed shall be calculated using approved engineering methods to assure the return of the cement to the surface. In the event cement does not return to the surface, the district Inspector shall be notified. If the top of cement cannot be located using sound engineering practices approved by the chief or his authorized representative, then an electric log or similar technology approved by the chief shall be used. Sound engineering practice approved by the chief or his authorized representative shall be used to fill the annular space back to the surface. Requests to approve methods, other than pre-approved practices, shall be acted upon by the chief or his authorized representative within twelve (12) hours of actual notice to the chief or his authorized representative, otherwise the request will be deemed approved. In no case shall the fresh water casing penetrate salt water or extend below sea level. There shall be no oil and gas production through the fresh water casing for new wells or the redrilling of existing wells permitted on or after August 1, 1993. Variances from the requirements of this section shall be granted on a site specific or area basis in accordance with section 16 of this rule.
5.2. Casing When Drilling Encounters Coal Seams.
5.2.a. Coal Protection String - Except for those coalbeds which the coalbed methane operator proposes to complete for production or produce from, or where a ventilation hole is being converted to a well, when a well penetrates one or more workable coalbeds, the well operator shall run and cement a string of casing in the hole through the workable coalbed or beds in such a manner as will exclude all oil, gas or gas pressure from such coalbed or beds, except such oil, gas or gas pressure as may be naturally present in each coal seam. Such string of casing shall have cement circulated in the annular space outside the casing. The casing shall either be cemented to the surface or at least into the fresh water casing to at least 100 feet above the uppermost workable coal seam. If the casing is not cemented to the surface, the operator will demonstrate that the casing has been cemented to 100 feet above the uppermost workable coal seam. The volume of cement needed shall be calculated using approved methods to assure cementing to the required level. In the event cement does not return to the required level, every reasonable attempt will be made to fill the annular space by introducing cement from the surface.
The fresh water casing may be extended through the workable coal seams and also serve as the coal protection string provided the casing is cemented as required in subsection 5.1 through the fresh water horizons, and subsection 5.2 through the workable coal seams, and subdivision 5.2.b regarding when a worked-out coal seam is encountered.
5.2.b. When Drilling Encounters a Mined Zone - Except where the horizon of a previously mined coalbed and its associated gob are expected to be the producing zone, when a coalbed methane well is drilled through the horizon of a coalbed from which the coal has been removed, the hole shall be drilled at least thirty feet below the coalbed, of a size sufficient to permit the placing of a liner which shall start not less than 20 feet below the coal seam and extend not less than 20 feet above the void created by the mined area. This liner, which may be welded to the casing being used, shall be centered in the borehole, and the space between the liner and casing shall be filled with cement as they are lowered into the hole. Cement shall be placed in the bottom of the hole to a depth of at least 20 feet to form a sealed seat for both liner and casing.
Following the setting of the liner, drilling shall proceed in the manner provided in subdivision 5.2.a. Should it be necessary to drill through the horizon of two or more workable coalbeds from which the coal has been removed, such liner shall be started not less than 20 feet below the lowest such horizon penetrated and shall extend to a point not less than 20 feet above the highest such horizon, provided that, where two or more horizons from which the coal has been removed are sufficiently far apart, separate liners for each horizon or combination of horizons from which coal has been removed may be used. In any event, each segment of liner shall start not less than 20 feet below the lowest such horizon penetrated and extend to a point not less than 20 feet above the highest such horizon.