The Research On Well Structure Design Technology Of Deep Water Drilling

With the continuous growth of oil and gas consumption,the deep water area become the focus of petroleum exploration and development.However,there are many problems and challenges in deep water drilling,such as narrow density window,conventional well body structure design technology can not meet the exploration of deep water oil and gas needs.Therefore it is very important for China's deep water oil and gas exploration and development to study the design technology of well structure that can be applied to the deep water area.In this paper,through the research and analysis of the relevant technology of the well structure design,expounds and analysis the application of the structure design technology for deep water drilling.The load and real-time capacity of catheter during the process of cementing in two extreme limiting condition is researched and analyzed;Combine with soil mechanics and pile foundation theory,the time effect of soil bearing capacity is considered,a depth calculation model of pipe based on two kinds of limit conditions is established;A new design method of the depth of the pipe is obtained through the software programming and the example verification.Through the research and analysis of conventional method for obtaining the formation pressure.And the pressure prediction method applied to deep water drilling is analyzed.The prediction of overburden pressure by using the density trend line method based on exponential model is proposed;The pressure prediction methods that based on probability statistics are used to predict the formation pore pressure,this method combines with the Eaton method and single point calculation model to establish the credibility of formation pore pressure profile curve and it improves the accuracy of the prediction model in Eaton index distribution model by joining the lognormal distribution model;The pressure prediction method based on probability statistics is used to predict the formation fracture pressure and caving pressure.The basic parameters of well structure design such as wave pressure coefficient are studied and analyzed,through the study of formation pressure prediction method based on probability statistics,the safety drilling fluid density window with confidence is studied and analyzed.For deep water drilling environment,based on conventional well structure design method,the design technology of deep water well structure is studied and analyzed,and the results are verified by an example.In this paper,the depth calculation model of the pipe into mud has been innovative and a new method for the design of the depth of the pipe into mud was obtained.But the reliability and accuracy of the results need to be further verified.