The Design Of The Automatic Ball Dropper For Horizontal Wells Staged Fracturing

As a new clean energy, Shale gas is becoming a hot spot of global energy development. Compared with the conventional natural gas, the resource potential of Shale gas may be greater than the conventional natural gas. But Shale gas reservoir has the characteristics of extremely low porosity and low permeability. The flow resistance of Shale gas is bigger than conventional natural gas and it is without natural capacity or low yield, so recovery efficiency is very low and it is unable to realize economical mined on a large scale. If we employ the traditional production way, it will increase the difficulty of Shale gas reservoir’s development. In order to achieve economic exploitation, Shale gas reservoir is needed to be fractured. The exploitation ways of Shale gas is mainly horizontal well staged fracturing, this way of exploitation can communicate natural micro fracture and artificial fracturing cracks maximally thus increasing the production of Shale gas. The stratified horizontal well fracturing technology have many kinds of technology, each technology has its corresponding fracturing tools. Pitching fracturing technology is one of the main technology of horizontal well staged fracturing, pitching fracturing technology rely on ball dropper to complete fracturing, therefore ball dropper has played a big role in the horizontal well staged fracturing.This paper analyses the deficiency of domestic existing ball dropper and the advantages of foreign ball dropper. Combining the characteristics of shale gas and exploitation conditions, On the basis of the original ball dropper, the paper has designed a ball dropper which can pitch continuously and automatically. This type of ball dropper will change the domestic original manual type of drive mode. The ball dropper not only can save the time of pressure relief, improve the efficiency of fracturing operation, but also can reduce labor intensity, the cost of production. In order to ensure the safety of workers, the ball dropper is able to work remotely under harsh environment. This ball dropper can change the situation that we must rely on foreign expensive wellhead ball dropper to complete fracturing. The paper introduces the design process of the parts of ball dropper and the control system in detail, and analyses the feasibility of the ball dropper. The paper makes finite element analysis for its major parts, and selects new materials or optimizes the results of the parts of insufficient strength. At last, this paper has successfully designed a new ball dropper which can meet the need of Shale gas’ s exploitation way.