25 Pa. Code § 78.97
Where strata bearing or having borne oil, gas or water in the well have been stimulated with explosives, thereby creating cavities which cannot be readily filled as described in §§ 78.92-78.95, the well operator shall place at the nearest suitable point, but at least 20 feet above the stratum, a plug of cement which extends at least 50 feet above that point. If the stimulation has been done above one or more strata bearing or having borne oil, gas or water in the well, plugging in the applicable manner specified in §§ 78.92-78.95 shall be done at the nearest suitable points, to at least 20 feet below and at least 20 feet above the stratum stimulated. From a point immediately above and below these plugs, the well shall be plugged under §§ 78.94 and 78.95 (relating to wells in noncoal areas-surface casing is not cemented or not present; and wells in noncoal areas-surface casing is cemented).
25 Pa. Code § 78.97
This section cited in 25 Pa. Code § 78.86 (relating to defective casing or cementing); 25 Pa. Code § 78.91 (relating to general provisions); and 25 Pa. Code § 78.407 (relating to plugging gas storage wells).