NUMERICAL COMPUTATION STUDIES AND HYDRODYNAMIC ANALYSIS ON THE CUTTING-CARRYING AND LIFTING CAPACITY OF SPIRAL CENTRALIZER IN GAS DRILLING

摘要

For gas drilling, hole cleaning is a particularly critical problem. When the spiral centralizer is used in the down hole assembly of gas drilling, it will produce a powerful rotational flow which will be bond to have the influence of different level on the hole cleaning. For this matter, this paper has established a three-dimensional fluid dynamics model in the basis of gas-solid two-phase turbulent theory and got its numerical solution by using the finite volume method, therefore making a quantitative evaluation about the ability of cutting-carrying and lifting of the spiral centralizer. The results have shown that the spiral centralizer has the function of cutting-carrying and lifting; part of the rock debris pellet concentrates in the bottom of the blade, above less instead. The numerical calculation method has some guiding significance for spiral centralizer design in gas drilling.