Research On Rock Drillability Prediction And Bit Selection Method

Rock drillability is a most comprehensive parameter reflection of the nature of the formation,is the drill bit selection and bit structure design of the important basis.In the process of drilling wells without adjacent well data,can not be calculated in real time rock drillability grade value;during the drilling of the development well,the geologic structure is complicated and the stratigraphic nature will change,causing the drill bit to not match the formation of real-time drilling.Therefore,it is necessary to obtain the real-time rock drillability grade value by analyzing the while drilling data,and use it for dynamic optimization of the drill bit.The emergence of logging-while-drlling technology provides the conditions for establishing a real-time calculation model of logging rock drillability.Based on the characteristics of nonlinear mapping ability of neural network,this paper establishes a logging drillability real time calculated neural network model.The model can be used in real-time calculation of rock drillability under the condition of with logging-while-drlling.Based on the real-time mud logging data of access route simple and convenient,a mud logging rock drillability real-time computational mechanics model can be established.The model only needs real-time mud logging data,which can be calculated without experimental data.The limited conditions are the least.In order to further improve the calculation accuracy and reduce the random error,the neural network model of mud logging rock drillability real-time calculation is built These two models can be used for rock drillability real-time calculation without logging-while-drilling data.According to the predictability of the rock drillability along the depth,the rock drillability real-time prediction model is established.The real-time prediction of the rock drillability grade value can be used to guide the bit selection of the undeveloped formation.By analyzing the rock drilling parameters and the rock mechanics parameters of the corresponding strata,the properties of the formation drilled by the drill bit are reflected by the rock mechanics parameters.The drill drilling parameters and the rock mechanics parameter database are established.Based on the established database and real-time calculation and predict rock drillability grade value is obtained,and the dynamic evaluation and dynamic optimization method of the drill bit are put forward.According to the above research,this paper in the Visual Studio 2013 development environment,the use of C#language software,the use of SQL Server 2008 for data management,developed a rock drillability prediction and bit selection software.The software can be based on logging data and mud logging data,real-time calculation and prediction the rock drillability,and will be used to guide the drill bit dynamic evaluation and dynamic optimization.Using the field data to verify the reliability of the model and the stability of the test software,the results calculated using the software are consistent with the actual situation,indicating that the established model has practical engineering significance,can be used to guide the construction site;the development of software can be stable operation Will provide technical support for shortening drilling time and reducing drilling costs.