Method and relative system for the identification of malfunctionings of the drill bit during the drilling of hydrocarbon wells

Method for the identification of malfunctioning of the drill bit during the drilling of hydrocarbon wells with the following steps:

• measurement of the drilling depth, obtaining a first time series of the values assumed by said drilling depth, said first time series being stored in a computer;
• measurement of the rate of penetration of the auger during drilling, obtaining a second time series of the values assumed by said rate of penetration, said second time series being stored in a computer;
• extraction of the drilling mud;
• degassing of said drilling mud;
• wherein the method further comprises the following steps:
• measurement of the concentration in the drilling mud of at least one gas species belonging to the group of the alkenes, obtaining of at least one third time series of the values assumed of said concentration of said at least one gas species, said at least third time series being stored in a computer;
• for each sample of said second time series, comparison of the value of the rate of penetration corresponding to said sample, with a first threshold value, said step of comparison being carried out by the processor of a computer;
• if the value of said rate of penetration, at a time sample, is below said first threshold value, performing of the following operations:
• calculation of the mean value of said rate of penetration, over a time interval, said interval beginning at said time sample and said interval and comprising a sufficient number of time samples for covering an interval of drilling length greater than or equal to a second threshold value, said operation of calculating the mean value being performed by a processor of a computer;
• comparison of said mean value with said first threshold value, said operation of comparison being performed by a processor of a computer;
• for each sample of said third time series comprised in said time interval, comparison of the value of concentration of said at least one gas species with a third threshold value, said operation of comparison being performed by a processor of a computer.