58 Pa. Stat. § 4
Upon abandoning or ceasing to operate any well or wells which shall have been drilled or put down on lands within this Commonwealth for the purpose of exploring for or producing oil or gas, the person, firm, or corporation, drilling or owning the wells, shall plug said wells in the following manner: First. Fill up the well with rock sediment to a point twenty (20) feet above the top of the lowest oil or gas bearing strata or formation encountered, and drive a round, seasoned, wooden plug, at least three (3) feet in length, equal in diameter to the diameter of the well below the casing, and shall, in like manner, keep plugging and filling until all producing sands have been plugged, when a final plug must be anchored approximately ten (10) feet below the bottom of the largest casing, and filled in with such an amount of rock or rock sediment that may be necessary to completely shut off any water bearing sands or strata; said fill, however, shall in no event be less than thirty (30) feet in depth. All plugs used in said wells shall be well seasoned, round, wooden plugs of the diameter of the well at the point at which said plug shall be located. They shall be at least three (3) feet in length, and the lower end thereof tapered for a distance of eighteen (18) inches. In abandoning any well which has been drilled through marketable coal, after the inside casing has been drawn, there shall be placed a two (2) inch vent pipe extending from a point thirty (30) feet below the coal bed for a distance of eighty (80) feet in height; said pipe to be encased in cement, after which the outside casing may be drawn.
58 P.S. § 4