INVESTIGATION OF THE STRESS STATE OF CASING PIPES IN DRILLED WELLS

The design features of casing pipe during descent and afloat are considered. A development model for studying the stress-strain state of the pipe in the zone of sticking with the bottom is presented. We consider design features of the casing during descent it afloat. The calculated model for the study of stress-strain state of pipes in the агеа of interface with the bottom.When drilling large-diameter wells, as a rule, the lifting capacity of the drilling rig is selected based on the weight of the casing string that is to be lowered into the well. If the weight of the string exceeds the lifting capacity of the drilling rig, three special methods of lowering the string are used: on an air cushion, afloat or in sections. Recently, the most common method of lowering strings in sections, but it is associated with a significant increase in the time of well casing, and cases of loose joining of sections are not excluded, which complicates plugging and subsequent operation of the wells. Lowering the string afloat is the simplest and most effective method, but is limited by the permissible external pressure on the string. Lowering the string on an air cushion is free from the disadvantages of the previous methods, but is associated with a reduction in the technology of lowering and the need to use special devices. Thus, the urgent task is to determine the most rational method of lowering depending on the mining and geological parameters of the well and the design features of the pipe. To solve this problem, it is necessary to study the stress-strain state of the pipe during the descent. Keywords: pipeline, external pressure, corpus column, tension, deformation, diameter, circumferential force.