ANALYSIS AND CALCULATION OF VERTICAL WELL PRODUCTION STRING STRESS BASED ON THE FRICTION GAP ELEMENTS.

In view of the problem of tubing breaking, based on the situation that real contact state of the oil production pipe strings could only be classified into 3 categories and 4 kinds, a double layer static force model is set up for analysing the contact system between sucker rod, tubing strings, and casing. The general balance equations and the conditions for the solution of the system are given. The comparison has been made between the calculated value based on the model and the measured values of the suspended point load. The error is with 15%, which meet the engineering requirement. [ABSTRACT FROM AUTHOR]