The Method Of Three Pressure Visualization Based On 3D Geologic Model

Wellbore stability is an important issue in drilling technology that specialists has been working on for decades.The scientific basis of keeping wellbore stability is building accurate profile of pore pressure(P_p),collapse pressure(P_c)and fracture pressure(P_f).Most previous researches and solutions only focus on 2D display which is not intuitive enough for the whole development block.Therefore,this thesis carrys out researches about how to calculate and display P_p,P_c,P_f of a 3D geologic model,proposes individual well data extraction method based on the results,which can be the basis of wellbore stability analysis and drilling fluid design.The achievements of this thesis are as follows:(1)Theoretical models of predicting P_p,P_c,P_f.Abnormal pressure forming mechanism and prediction method of P_p using Eaton formula is expounded.Based on the wellbore surrounding rock stress expression of both vertical well and directional well,as well as Mohr-Coulomb strength failure criteria,the prediction models of P_c and P_f are formed.(2)3D geologic model establishment and meshing.In this thesis,the software GiD is chosen for 3D geologic model establishment and meshing.For improving the efficiency,two methods are built for automatic modeling using GiD,which are 1)sending commands to GiD from external Python program and 2)generating the inner macro of GiD using Python and run it manually.(3)P_p,P_c,P_f calculation and display of the 3D geologic model.Logging data of the geologic model is generated from all the individual well logging data using inverse distance weighted interpolation(IDW).With the pore pressure coefficient results,structural stress coefficient results and strength coefficient of the study area,P_p,P_c,P_f of the3D geologic model are calculated.Through Mayavi,highly customized,interactive display of the prediction results can be easily made.In terms of individual well,this study forms a data extraction method and error analysis is carried out of the extraction result.(4)Software programming.Based on the theories and results above,a well-organized,concise and easy-to-use software is made for P_p,P_c,P_f calculation and display of the 3D geologic model,which can be a reliable tool for implementation of the methods dicussed in this thesis.The function modules are as follows:1)logging data tidy module,2)parameter calculation module,3)GiD macro generating module,4)inp file tidy module,5)pressure calculation and display module,6)well track display and data extraction module.The UI code and logical code of the software are seperated.