61. An exploration licensee or production lessee for petroleum and natural gas, brine or an underground reservoir shall, where operations of a well, whether drilling, completing or modifying, are permanently stopped, abide by the following rules:(1) a cement plug having a length of not less than 30 m must be placed at the bottom of the well;
(2) each permeable zone of the well must be isolated by means of a cement plug, which must not be less than 30 m in length when placed in a part of the well unprotected by a casing, nor less than 10 m in length when placed in a part of the well protected by a casing;
(3) a cement plug having a length of not less than 30 m shall be placed across the surface casing shoe when this casing is the deepest casing string in the well;
(4) in the case of an onshore well, each casing shall be sectioned at 1 m below ground, a cement plug shall fill in the last 10 m of intermediate casing, and a steel plate having a thickness of not less than 1 cm shall be welded to the outer casing opening;
(5) in the case of a well in a water-covered area, each casing shall be sectioned at at least 2 m below the surface of the seafloor, a firing hole plug shall be placed in the internal casing at 150 m below the seafloor and those 150 m shall be filled with a cement plug;
(6) the exact position of the top of any cement plug must be verified by means of a string of rods at least 12 hours after setting the cement plug, if it is located:(a) level with the deepest casing shoe string;
(b) above an abnormal pressure zone;
(c) above a zone containing hydrocarbons;
(7) an onshore well must be identified by means of a steel plate 15 cm wide and 30 cm high indicating in relief the name of the well and its geographic coordinates. The plate must be fastened by a steel rod at 1.5 m above ground. When the steel rod is not welded to the outside casing, the plate must also indicate in which direction and at what distance the well is located;
(8) the well shall be left in a condition preventing any fluid or gas flow outside the well.