The Application Of Finite Element Method In The Strength Analysis Of Casing After Hydraulic Sand Blast Slotting And The Optimization Of Its Technological Parameters

In order to answer the question if hydraulic sand blast slotting will lead to casing damage and how to optimize the technique to diminish its influence on the strength of casing , they studied by limited element numerical modeling and field test. First, they had a cement target test. From this test, they obtained the accurate slot shape in casing and formation. On this basis, they calculated separately the effect of Hydraulic Sand Blast Slotting and shaped charge shooting on the Strength of Casing. By comparison, their effects on the strength of casing are almost identical. At the same time, they optimizing the technological parameters (the length of slits, 2 or 3 slits in a group, the minimum distance between two consecutive groups, the phase angle between two consecutive groups). They got such conclusions: in order to protect casings , the biggest length of every slits would be less than 20 cm, the amount of slits in every group would be 2, the distance between two consecutive groups would be from 37cm to 100 cm , two consecutive groups of slits would be crossed. Because some wells are designed as 2 slits in a group, and others are designed as 3 slits. With limited element program, they studied not only their effect to the strength of casings, but also their liquid-producing capacity. These comparison will be important to the optimization of two styles.All these studies in this paper will lay a theoretical foundation for the extensive application of hydraulic sand blast slotting .