An Analysis&Caculation Of Rock Mechanic Parameters In Sulige

With the ever-development of petroleum drilling technology, the techniques of MWD.LWD. FEWD and real-time measurements of downhole parameters have been improved andput into wide use in oil field, with which a great deal of downhole information are obtained.Evaluation and calculation of rock mechanic parameters with the downhole information arevery important for drilling with safety and high speeds. For this purpose, the methods toevaluate and calculate rock mechanic parameters with information are completely analyzedand studied in this paper. Some models to calculate and evaluate rock mechanic parameters inSulige gas field and criteria to describe wellbore stability are developed. The main contents ofthis paper are as follows.In the first, the methods, published out of the world, to calculate and evaluate theformation rock mechanic parameters and earth stresses in situ with data from MWD&LWDare analyzed to a large extent. Some calculation mathematics models for those parameters arechosen.The second point of the paper is how to calculate the rock mechanic parameters.usingexsisting logging information.The third pari of this paper lies in studying and analyzing the wellbore instability criteiraand their application in oilfield. The stress distributions around the wall of wellbore aredetermined. The results calculated from More-Colum, Drager-Prager, and Lade criteria areanalyzed and compared, the results of which prove that the modified Lade criterion is themost suitable one in wellbore stability analysis. Many data from oilifelds support the aboveconcludes.As the fourth aspect of this paper, the above theories, methods, models and criteria arestudied and put into wide application. The calculation and evaluation of formation rockmechanic parameters and the determination of wellbore stability by the means of data fromdrilling in Sulige oilifeld are carried out. Comparison of calculation results to practicalmeasurement results shows that calculation is confident and with very high precise. Theproper limits of drilling fluid density are calculated to enable the wellbore of drilling stable.