Oriented and sand control hydra jet fracturing in coalbed methane horizontal wells and field applications

Coalbed methane resources is abundant in China. But low single well daily production，difficult stimulation and short stable production time are the bottlenecks for efficient development of coalbed methane. In addition，it is common to shut down Wells due to sand production，which seriously restricts the exploitation efficiency of coalbed methane. Hydrajet oriented multistage/multicluster fracturing technology is developed for pinpoint and oriented network fracturing. The abrasive jet perforation，hydraulic isolation，network fracturing，and precise orientation are integrated into this technique. Oriented perforation and fracturing are achieved by using the “antigravity”method to increase production and effectively control sand. No. 3 coal seam in Zhengzhuang block，Qinshui Basin，Shanxi Province is taken as the object of stimulation，2 Lshaped horizontal wells were fractured. Oriented perforation was carried out in the direction of 4 o’clock and 8 o’clock，which achieved a good dual effect of production enhancement and sand control. The results show that:① There are 10 fracturing stages in ZX-1L well and 10 fracturing stages in ZX-2L well (consists of two clusters in one stage，with a cluster spacing of 10 m). The average sand amount in each stage of the two wells is 50 m 3 and 800 m 3 respectively. The fracturing was successful，and there are no problems of fracturing fluid loss，interzonal crossflow and sand plugging. ② The stable daily gas production of the two wells is 10 100 m 3/d and 16 000 m 3/d，respectively，and the time for production increment is one month when the daily gas production reaches 10 000 m 3/d，which has the characteristics of fast production increment speed and high stable gas production. The daily gas production is 5-9 times that of vertical wells and 1.4-2.3 times that of horizontal wells in the same block. ③ The water samples taken from 2 wells showed that the water quality was relatively clear，and no sand was produced. The production equipment ran smoothly. This technology can be widely applied to roof and floororiented fracturing in tectonic coal seam and oriented crossseam fracturing in multilayer/thin interbed，which is expected to provide a new technical idea and stimulation method for the enhancement of coalbed methane production.