Modeling And Analysis Research Of Dynamic Cuttings Transport In Extended Reach Well

Cuttings transport is one of the key technologies of extended reach well drilling.The real-time and intelligent drilling technology has become the general trend in the industry.It is of great significance to carry out the research on the dynamic cuttings transport law,understand the real-time cuttings distribution profile of extended reach well and monitor the hole cleaning status in the wellbore in real time.Aiming at the problem of rock carrying in annulus,this paper takes the whole well section of extended reach well as the research content,consults the domestic and foreign literature,investigates the mechanism of cuttings transport,analyzes the flow pattern of cuttings transport,establishes the method of automatic flow pattern discrimination,comprehensively considers the flow pattern and flow pattern conversion conditions of cuttings transport,and uses the equations of mass conservation and momentum conservation to take the extended reach well as a whole,and establishes a simulation integration method Dynamic cuttings transport model of cuttings distribution,location and influence on annulus pressure in wellbore during drilling process,and the law of cuttings transport was studied through experiments.The main research work of this paper is as follows:(1)the first mock exam of the whole well section of the extended reach well is conducted to investigate the flow pattern transformation mechanism,and establish the automatic identification method of the cuttings transport flow pattern,which provides the basis for the unified model of dynamic cuttings transport.(2)Combined with the flow pattern of cuttings transport,the unified dynamic cuttings transport model of extended reach well is established by using the mass conservation and momentum conservation equations;(3)In view of the uncertainty of various parameters in real-time drilling process,a model self correction method is developed to make accurate and timely judgment and decision-making when there are certain uncertain factors in the input data;(4)The accuracy of the dynamic debris transport model is verified by the flow solid coupling intelligent experimental platform of Yangtze University.The effects of drilling fluid displacement,rotation speed,ROP and well inclination on cuttings transport and annulus pressure consumption are analyzed through experiments;(5)Based on the established model,the vs2017 integrated development environment is used to develop real-time monitoring software for borehole cleaning status,and the whole process and change rule of cuttings transport and accumulation in the borehole are monitored in real time in combination with field drilling data;Based on the research results,the distribution of cuttings in the wellbore can be monitored in real time,which is of guiding significance for the prevention of cuttings accidents in extended reach wells.