MODERNIZATION OF THE LABORATORY BENCH FOR RESEARCHING THE STRESS AND DEFORMATION STATE OF THE MODEL OF THE DRILL STRING SECTION

Abstract

Evaluation of drill strings stress-strain state during their operation in the wells with random change of zenith and azimuth angles, non casing sections of well walls and dog-legs is very important scientific and practical prob-lem. One of the methods of its solution is the physical modeling of the "drill string – wellbore" system. On the basis of scientific works analysis in mentioned above field, aim of this article is formulated as modernization of the la-boratory test bench existing construction with the aim of explore stress-strain state of the drill string models in the wells with random curved axles with consideration of tension or compression forces and torque. In particular, support unit was rebuilt and made of steel profiles as rigid truss. Restriction of displacement of the one end of the drill string model was get as result. Also, loading unit is modified by the additional pulleys. As result we got possibility to load opposite end of the drill string model by the tension or compression axial force. Resistive foil strain gauge method is used for indirect measuring of the stresses in the drill string model cross section. Statistical anal-ysis of the results was operated by the Dixon’s criterion that is used for small experimental data samples. It gave possibility to separate incorrect values of the voltage on the resistive foil strain gauges and doesn’t use them for calculation of the stresses in the cross section of the drill pipe or its model. Was mentioned that further improving of the test bench construction will consist of adding of the electric motor for possibility of rotation of the drill string model and providing of the experiment in the dynamic mode.