Method of Evaluation of Deposits and Opening of Productive Formations

Abstract

In a method of evaluation of deposits and opening of productive formations in recovery of oil or gas, a previously drilled well is located and investigated to determine at least one first zone which is not productive for oil or gas extraction and at least one second zone which is productive for oil or gas extraction; the at least one first zone which is not productive for oil or gas extraction is skipped, while hydroslotting is performed in the at least one second zone by making a plurality of slots and thereby producing unloaded regions so as to provide again a flow of oil or gas in the previously drilled well which was not in operation.

What is desired to be protected by Letters Patent is set forth in particular in the appended claims: 
     
         1 . A method of evaluation of deposits and opening of productive formations in recovery of oil or gas, comprising the steps of locating a previously drilled well from which oil or gas was previously extracted and which is no longer in operation; investigating at least one formation in said previously drilled well from which oil or gas was previously extracted; determining by the investigation in said at least one formation at least one first zone which is not productive for oil or gas extraction; determining by the investigation in said at least one formation at least one second zone which is productive for oil or gas extraction; skipping in said at least one formation said at least one first zone which is not productive for oil or gas extraction; and hydroslotting in said at least one formation said at least one second zone by making a plurality of slots and thereby producing unloaded regions so as to provide again a flow of oil or gas in said previously drilled well which was not in operation. 
     
     
         2 . A method as defined in  claim 1 , wherein said investigating of said at least one formation in said previously drilled well which is not in operation includes using a radioactive method of investigation via which said at least one first zone and said at least one second zone are determined in said at least one formation. 
     
     
         3 . A method as defined in  claim 1 , wherein said investigating of said at least one formation in said previously drilled well which is not in operation includes using a method of nuclear logging via which said at least one first zone and said at least one second zone are determined in said at least one formation. 
     
     
         4 . A method as defined in  claim 3 , further comprising providing in said method of nuclear logging transmission of signals to said at least one formation, receiving signals reflected from said at least one formation and evaluating the reflected signals to determine said at least one first zone and at least one second zone. 
     
     
         5 . A method as defined in  claim 1 , further comprising performing said hydroslotting by making said slots extending in a direction which is perpendicular to a direction of maximum stresses in near-well zone of said previously drilled well which is not in operation. 
     
     
         6 . A method as defined in  claim 1 , further comprising performing hydrosolotting by making said slots extending in direction which is perpendicular to a directions of cracks in a near-well zone of said previously drilled well which is not in operation. 
     
     
         7 . A method as defined in  claim 1 , wherein said determining includes evaluation of costs of extraction of oil or gas from said at least one first zone and at least one second zone, evaluation of quantities of oil or gas which can be excavated from said at least one first zone and said at least one second zone, considering said at least one first zone as a not productive zone when the cost of the quantity of oil or gas extracted from it is lower than the cost of extraction of oil or gas from it, and considering said at least one second zone a productive zone when the cost of the quantity of oil or gas extracted from it is higher than the cost of extraction of oil or gas from it. 
     
     
         8 . A method as defined in  claim 1 , further comprising extending from said previously drilled well which is not in operation an additional inclined well going to said at least one second zone, and extracting oil or gas from said at least one second zone via said additional inclined well.