§ 78a.85. Cement standards.
(a) When cementing surface casing or coal protective casing, the operator shall use cement that meets or exceeds the ASTM International C 150, Type I, II or III Standard or API Specification 10. The cement must also:
(1) Secure the casing in the wellbore.
(2) Isolate the wellbore from fresh groundwater.
(3) Contain any pressure from drilling, completion and production.
(4) Protect the casing from corrosion from, and degradation by, the geochemical, lithologic and physical conditions of the surrounding wellbore. For wells employing coal protective casing, this includes, but is not limited to, formulating cement to withstand elevated sulfate concentrations and other geochemical constituents of coal and associated strata which have the potential to adversely affect the integrity of the cement.
(5) Prevent gas flow in the annulus. In areas of known shallow gas producing zones, gas block additives and low fluid loss slurries shall be used.
(b) After the casing cement is placed behind surface casing, the operator shall permit the cement to set to a minimum designed compressive strength of 350 pounds per square inch (psi) at the casing seat. The cement placed at the bottom 300 feet of the surface casing must constitute a zone of critical cement and achieve a 72-hour compressive strength of 1,200 psi and the free water separation may be no more than 6 milliliters per 250 milliliters of cement. If the surface casing is less than 300 feet, the entire cemented string constitutes a zone of critical cement.
(c) After any casing cement is placed and cementing operations are complete, the casing may not be disturbed for a minimum of 8 hours by doing any of the following:
(1) Releasing pressure on the cement head within 4 hours of cementing if casing equipment check valves did not hold or casing equipment was not equipped with check valves. After 4 hours, the pressure may be released at a continuous, gradual rate over the next 4 hours provided the floats are secure.
(2) Nippling up on or in conjunction to the casing.
(3) Slacking off by the rig supporting the casing in the cement sheath.
(4) Running drill pipe or other mechanical devices into or out of the wellbore with the exception of a wireline used to determine the top of cement.
(d) Where special cement or additives are used, the operator may request approval from the Department to reduce the cement setting time specified in subsection (c).
(e) The operator shall notify the Department a minimum of 1 day before cementing of the surface casing begins, unless the cementing operation begins within 72 hours of the start of drilling.
(f) A copy of the cement job log shall be available at the well site for inspection by the Department during drilling operations. The cement job log must include the mix water temperature and pH, type of cement with listing and quantity of additive types, the volume, yield and density in pounds per gallon of the cement and the amount of cement returned to the surface, if any. Cementing procedural information must include a description of the pumping rates in barrels per minute, pressures in psi, time in minutes and sequence of events during the cementing operation.
(g) The cement job log shall be maintained by the operator after drilling operations for at least 5 years and be made available to the Department upon request.
Cross References This section cited in 25 Pa. Code § 78a.81 (relating to general provisions); 25 Pa. Code § 78a.102 (relating to criteria for approval of inactive status); and 25 Pa. Code § 78a.103 (relating to annual monitoring of inactive wells).
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