Study On Parameters Design And Use Of Slim-hole Drilling Hydraulic

Variations in annular geometry, tool-joint, eccentricity and pipe rotational speed strongly affect pressure loss of a fluid flowing in the narrow annulus of a slim-hole well. Due to these factors, accurately calculating and controlling pressures in the slim-hole well are very difficult. Attempts to model non-Newtonian fluid flow in narrow annuli with high-speed pipe rotation have been hampered by the lack quality data. Accurate pressure calculations are crucial for safely controlling formation pressures and protecting wellbore integrity with the help of establishing a new model.Based on the domestic and foreign research material about the slim-hole well technology, we establish the mathematical model of forecasting the tool-joint effect on the annulus pressure-loss. Moreover, we get the pressure-loss calculation equation of H-B fluid model, including effects of eccentricity, drilling string rotation and. drilling pipe joints. Through the experiment, we further understand the tool-joint rotational speed strongly effect on the pressure loss in the narrow annulus of a slim-hole well. According to the analysis of the experiment data, we get a calculation equation of annulus pressure-loss considering the tool-joint rotational speed strongly. Aimed to the characteristics of slim-hole drilling, an optimum hydraulic parameters design model is studied, including the effects of laminar flow and turbulent flow. Based on this model, we consummate the theory of optimum hydraulic parameters design and make a program of the slim-hole well hydraulic parameters design. Then, get a comparison between computational data and field data of two wells. It is proved that using the theory of optimum hydraulic parameters design in the study is more accordant to that of product well.