Auxiliary Fracturing and Testing of Gas in Shale Gas Well with Coiled Tubing

Coiled tubing has been widely used in shale gas development in China, there have been significant difficulties, such as tubing collapse, deformation, self-locking, low efficiency in drilling and milling, getting stuck and falling into the hole. Aiming to mitigate or eliminate these problems, relative analysis and technical investigation have been conducted at home and abroad, especially by using the high performance compound connector with small size, anti-drop PDM, five-blade concave mill, hydraulic oscillator and fishing accelerator, a integrated coiled tubing technology for supplementary fracturing and gas testing has been formed in shale gas development, including plug setting in long horizontal section, a drilling bridge plug, perforating, fishing and sand washing in an extended horizontal well. Field application demonstrated that by using the new techniques, the time of drilling one plug was reduced from 70 min to 40 min, the drilling plug cycle in a well reduced from 9 days to 5 days, drilling and removing rate of plugs raised from 97% to 100%, tubing collapse has not happened in perforating, the success rate of fishing and setting plug reached to 100%. All in all, the practice showed that the integrated technology could improve the success rate of fracturing and gas testing in shale gas wells.