Key Techniques for Eliminating Resistance while Running Liner with Circulation in Long Horizontal Openhole Wells in the Western Sichuan

In order to solve the problems of resistance encountered while running liner and the fact that it is often hard to run liner through the full extent of long horizontal openhole wells in the Western Sichuan Area, cementing pipe string liner was optimized to improve the reliability of liner cementing tools and to enhance the mobility of the liner cementing pipe string. Key tools such as pressure-balanced liner hanger, integral elastic centralizer, and elastic/buoyant floating collar were adopted, and the technical measures that can reduce the resistance encountering probability of liner and increase the success rate of resistance removal were formulated, through which the mid-way resistance removal technology for running liner in long openhole horizontal wells was formed with large flowrate circulation. The pressure-balanced liner hanger can eliminate the risk of premature setting caused by the pressure build-up during circulation or abnormal high pressure. In this case, the minimum resetting force of integral elastic centralizer is about 2 times that of the conventional single-bow elastic centralizer, and that can improve the casing centering. In the meantime, the elastic/buoyant floating collar can solve the problems of spring fatigue failure due to large flowrate long-term circulation and the erosion failure of back pressure valve seal in conventional spring-type floating collar. The resistance removal technology by mid-way large flowrate circulation has been applied to 50 shallow horizontal wells for running liners in long openholes in the Western Sichuan Area, and it solved the problems of getting hung up and getting out of design position in running liner. Using the new technique, the liner succssfully arrived at the end of the hole at the rate of 98%. The research results showed that this technology could solve the problems of running liner in long horizontal openhole wells in the Western Sichuan Area.