Overcoming Marginal Load Limits in Small Diameter Tubing Operations by Using Strain Gauge Measurements

Abstract

Because wells are becoming increasingly longer and more complex in trajectory and construction, safe operating limits for running pipe are becoming increasingly smaller. Because of narrow buckling margins in small diameter drillpipe and tubing, an accurate measurement of pipe tension is critical to ensure success when running this pipe. Severe buckling could result in tubing damage or failure, generating potentially significant non-productive time (NPT) or loss of the wellbore. Unreliable surface measurements for hookload and the need to measure minor changes in weights have created a need for the means to measure them. A fully validated and applicable solution is available to overcome these challenges. When run in conjunction with a measurement-while-drilling (MWD) toolstring, including a pressure-while-drilling (PWD) sensor, directional sensor, a controller module and pulser, the tool containing strain gauges provides real-time updates and stores data in memory, with tension readings at the sensor depth, to represent the weight of the string below that point. This paper presents two cases in which this solution was successfully applied, using strain gauges to measure tension below a point of interest in a string of pipe or tubing in non-drilling applications. Accurate torque and drag modeling with tripping-in weights and buckling limits plotted against real-time updates from the strain gauge tool provided continuous updates on the load regime downhole. This enabled the tension to be maintained above the buckling limits. Where the tension fell below the limits, remedial actions were taken or operations were carefully continued with extra vigilance for any signs of a deteriorating situation or of string lockup. The benefits of using strain gauges have been found in yet another non-drilling application described in this paper. Technology to measure tension that has been traditionally used in the improvement of drilling performance can also be applied to improve the performance in activities that pose the challenges of overcoming low operational margins.