A Research Of Well-bore Stability Theory In Drilling Process Of Erdos Basin Shale

Recently, the discovery of traditional energy resources is out of planned, therefore, thekey point of the energy’s management in nowadays society is exploring new kinds of energy.For now, developing the unconventional resources, like deeply oil&gas energy and shale gasenergy, is the best and the most effectively method to solve the lack of energy problem.Although the mud shale layer is the main constitution of shale gas, due to the well-boreinstability problem which mostly occurred in mud shale layer, it causes numbers of difficultiesto explore the shale gas energy. However, the purpose of this paper is going to study the theoryof well-bore instability, predict the rock mechanics parameters and give a better solution tosolve the instable problem in the process at drilling field.Based on the experimental and theoretical study of core and the combination of theprediction model of geological mechanics parameters, I am studying the well surroundingstress of mud shale stratum structure, summarying a systemed prediction method about thepressure of well-bore instability and collapse pressure in drilling process. There are thedetailed study contains:(1) through the data that come from the roch mechanics parameters from coreexperiments, the variety specific features of mud shale layer are summarized. Under the rockbreaking rules, analyzing the rocks’ compression pressure from different angles of core.(2) According to the study of stratum stress parameters, to get the magnitude anddirection of overburden pressure,pore pressure and crustal stress. All those data will be used tosupport the analysis of the well surrounding stress and the specific prediction of the drillingwell-bore stability.(4) Calculating the prediction profile of the three main pressures of vertical well is on thebasic analysis of the surrounding stress. In the mean time, providing the change regulation ofcollapse pressure by the changing of deviation and azimuth for the directional well.Furthermore, this paper also provides study about the changing regulation of collapse pressurewith borehole drilling changes of open time, and this study could make contributions to prevent the well-bore instability problem in the oil field process.The contains of this paper will make great contributions to the exploration of mud shalegas, and have a great influence on the effective developing of unconventional resources.