FIELD: well boring technology. SUBSTANCE: method includes step of determining time derivative of torque of boring pipes string during well boring at given time, when irregular rotation of boring pipes string base equipment occurs, step of determining nominal speed of pipes string rotation at its upper portion at given time, and a step of determining rotation rigidity of boring pipes string on basis of selected dependence between said time derivative of torque of boring pipes string and said nominal speed of pipes string rotation at its upper portion. System for measuring rigidity of boring pipes string, said string having boring pipes string base equipment and being driven into rotation at upper portion by means of rotation drive system. Said system includes means for determining time derivative of torque of boring pipes string during well boring at given time, when an irregularity occurs in rotation of boring pipes string base equipment, means for determining nominal speed of pipes string rotation at its upper portion at given time, and means for determining rotation rigidity of boring pipes string on basis of selected dependence between said time derivative of torque of boring pipes string and said nominal speed of pipes string rotation at its upper portion. EFFECT: increased precision of determining rotation rigidity of boring pipes string. 2 cl, 2 dwg
