Composite structure of the magnesium ball valve element for a drilling well

Abstract

In the oil industry, balls are used in the process of hydraulic fracturing (HF). The material that meets the basic requirements for HF balls is magnesium. Soluble magnesium balls are designed to activate HF couplings. When the coupling seat is reached, during the pumping of HF fluid, the ball temporarily blocks the passage section inside the shank column, which makes it possible to create excess pressure and open the windows of the HF coupling. However, since magnesium has a low density, in drilling fluids with a high density, leaky contact of the ball with the valve seat is possible due to insufficient gravity. This may lead to leakage of the working fluid. The purpose of the work is to create and study a method of manufacturing a ball aimed at weighing it down. The developed method of manufacturing a two-layer ball valve element by stamping is described. The two-layer ball consists of a magnesium shell, inside which a steel ball is placed. A steel ball is placed in a magnesium cylindrical glass with a bottom, the glass is closed with a magnesium lid. The resulting composite assembly is deformed by being compressed with two punches with ends in the form of hemispheres until the ends of the cylindrical cup are tightly closed. As a variant, the shell of the ball is proposed to be made of Mg90 grade magnesium. It is theoretically established that the mass of a bimetallic ball is 2.74 times larger than a magnesium ball. Modeling of stamping of a composite billet is performed in order to establish the possibility of obtaining a ball according to the proposed method. The stress-strain state of a composite billet in the process of shaping is considered. Successful computer simulation of the process gives grounds to recommend the proposed method for implementation in a real experiment. The smallest value of the ratio of the cylinder wall thickness to its height is also established, which ensures the stability of the cylinder wall during deformation.