Study on dynamic transport characteristics of cuttings during drilling and washing of long horizontal wells

In order to simulate the influence of well inclination angle on cuttings transport in the whole inclined section and horizontal section, we use cubic spline interpolation method to carry out curve fitting on the well trajectory, and establish a two-layer dynamic model of cuttings transport in long horizontal wells considering the actual well trajectory, and use MATLAB to simulate it. This study simulates the process of drilling and washing, analyzes the influence of the flow rates, the drilling fluid density, and the rate of penetration (ROP). Research results demonstrate that, under drilling conditions, cuttings are difficult to deposit in the section with small deviation angle, the degree of hole cleaning increases with the flow rates and the drilling fluid density, and lower ROP is helpful in hole cleaning. Under washing conditions, the smaller the deviation angle is, the worse the erosion effect is; the degree of hole cleaning increases with the flow rates and the drilling fluid density. The research results have guiding significance for hole cleaning of long horizontal wells.