High torque-and-drag (T&D) values can increase the difficulty of installing tubing in extended reach steam-assisted gravity drainage (SAGD) wells. Extra surface applied compressional force (tubing jacks) is often needed to land the tubing, leading to increased completion operation time and costs, and increased hazard potential. In many cases the likelihood of sinusoidal and helical buckling of the production tubing is also significant. A method of running tubing in extended-reach horizontal wells is presented which uses pipe floatation to reduce sliding friction in the lateral section. For SAGD wells in the subject area, the operator was able to eliminate the use of tubing jacks to run production tubing to the toe of the well. Data was acquired that allowed the comparison of tubing load conditions, both with and without the floatation method. This data was also compared with torque-and-drag (T&D) modeling results to illustrate the reduction in friction that was achieved and quantify the benefit of the method.
The method adapts principles used to float casing into wells to SAGD tubing installation, and moreover uses specifically designed floatation subs to increase the efficiency of the method. The floatation subs are used to trap air in sections of the tubing string in order to improve running forces. Once the tubing is landed, applied pressure is used to burst fragmentation domes within the floatation subs, leaving no obstructions in the tubing string.
In all trials of the float-in method, tubing was landed under its own weight, without using tubing jacks. In all of the conventional method wells, tubing jacks were needed to successfully land the tubing. Torque-and-drag models accurately predicted the point at which conventionally deployed tubing reached a neutral hookload.