Study On Borehole Wall Stability In Haita Basin

The problem of borehole instability is an extremely complex problem in the drilling process.It will cause great difficulties for drilling engineering.It will not only prolong the drilling cycle,but also greatly increase the cost of drilling.In order to solve the problem of borehole instability,scientific drilling is required for this purpose.Scientific drilling design requirements not only ensure that the target layer is drilled quickly and safely,but also comprehensively consider various aspects such as reservoir protection.However,for scientific drilling,it is necessary to first understand the geological conditions of a certain area and carry out a large amount of experimental research and analysis to be able to realize the complex geological conditions of the Haita Basin,resulting in many problems in the drilling process.For example: a series of problems such as well leakage,well collapse,expanding well diameter,drilling speed,well inclination,and failure of deep well drilling tools.In the face of this situation,this paper studies the stability of borehole wall in the Haita Basin in order to find a solution.In view of the geological conditions of the Haita Basin,this paper mainly conducted indoor experiments such as cation exchange capacity CEC,zeta potential measurement,shale recovery rate,expansion rate experiment,rolling recovery experiment,and shale activity measurement.The fuzzy comprehensive evaluation method was used to evaluate the stability of shale.The principle,existing problems and how to improve the method were analyzed in detail.At the same time,an example application was made.In order to better solve the problem of borehole instability in the Haita Basin,this paper also conducted an indoor evaluation of the general performance,inhibition,and reservoir protection of the drilling fluid in the Haita Basin.Based on the fracture development characteristics of mud shale in the Haita Basin and the mechanism of mud shale collapse in the Haita Basin,the anti-slough measures and problems that should be noted in the construction process are made.