Research On Monitoring Of Force Deformation Of Wellbore In Deep Vertical Wellbore Based On Optical Fiber Sensing Technology

The vertical shaft is the throat of the mine and an important channel connecting the ground and underground for the transportation of personnel and materials and equipment.In recent years,with the gradual development of coal resources in China from shallow mining to deep mining,the excavation depth of vertical wellbores has also increased year by year,and the safety of deep wellbores is facing more and more severe tests.Therefore,effective monitoring technology and theory are urgently needed to monitor the deformation of the well wall in real time,and judge the safety status of the well wall according to the monitoring data,so as to meet the needs of real-time and all-round early warning of the vertical wellbore under the current deep mining conditions.Based on optical fiber sensing technology,this study mainly conducts the following studies by means of theoretical analysis,numerical simulation,on-site monitoring and other means of theoretical analysis,numerical simulation,on-site monitoring and other means of monitoring the force deformation of the wellbore wellbore:(1)theoretical force analysis of the wellbore,(2)numerical simulation of the circumferential force of the wellbore,(3)on-site monitoring of the wellbore of the vertical wellbore,and the following conclusions are obtained:(1)Through the theoretical force analysis and research of the wellbore,the stress value of the inner edge of the wellbore under the action of horizontal uniform load and the horizontal non-uniform load is derived,and the internal force expression of the wellbore is deduced with the non-uniform load formula,and then under the action of uniform load and non-uniform load,respectively,the calculation and comparative analysis are carried out through engineering examples,under the action of horizontal nonuniform load,the circumferential stress distribution is uneven,between 0 and 90 degrees,the circumferential compressive stress value of the inner edge of the wellwall decreases with the increase of angle,and the maximum value is obtained at the 0 degree position.Therefore,0 degrees is also the most vulnerable location for damage to the well wall.(2)Through the numerical simulation study of the circumferential force of the wellwall,it is found that under the horizontal uniform load,there is no tensile stress in the wellbore at depths of 485 m,545m and 588 m,and the circumferential compressive stress value of the wellwall increases with the increase of depth.The internal force of the well wall under the action of non-uniform load is more significant than the force under the action of uniform load,the distribution of the circumferential compressive stress size of the inner edge of the well wall has a certain relationship with the angle,with the increase of the degree of unevenness,the numerical simulation calculation is carried out at the depth of 588 m,the circumferential compressive stress value at the 0 degree position of the inner edge of the well wall increases,there is no tensile stress inside the well wall,and the maximum compressive stress value is still within the bearing capacity range,indicating that the wellbore is always in a safe state.(3)The force deformation monitoring of the wellbore adopts three sets of monitoring systems,namely steel string sensor,fiber grating sensor and distributed optical fiber,which monitors the concrete ring and vertical strain of the well wall in real time,collects data regularly for analysis,calculates the early warning value of different depths of the well wall and the monitoring results is compared and analyzed,and the force state of the well wall is determined,and finally the well wall is always in a safe state.Figure[61] table[14] reference[83]...