Research On Stress Measurement While Drilling Technology

Weight on bit,torque and bending moment are important parameters in the drilling process.Due to the complex actual situation in the well,the acquisition of these engineering parameters facilitates the ground technicians to make correct decisions on the downhole conditions,thereby promoting the smooth progress of the drilling project.According to the background of the current stress measurement while drilling technology,this paper studies a design scheme of downhole engineering parameter measurement sub,which is used to collect and store the stress of drill collars in real time.For this measurement pup system,the layout and design of the sensor are first studied,and the same 15-15 HS MAX non-magnetic stainless steel as the drill collar material is selected as the base material.The sensor determines that the patch mode of the strain gauge on the short joint is orthogonal four holes.The pattern of the strain rosette and various parameters of the strain resistance grid are designed,and the ANSYS software is used for simulation analysis under different loads,so that the output response of the sensor can be optimized.Secondly,the measurement algorithm of tensile pressure,bending moment and bending moment direction is deduced through theoretical research,and the problem of the influence of structural coupling and environmental coupling on the measurement results is solved.The output response characteristics of the sensor and the compensation algorithm under the influence of temperature and hydraulic pressure are studied.In order to overcome the influence of the harsh underground environment,a relatively novel compensation algorithm,namely the dual excitation power supply method,is studied,which realizes the comprehensive compensation of temperature and hydraulic strain by supplying dual power supply to the Wheatstone bridge.Finally,the hardware design of the measurement system is studied,and the limiting factor of downhole high temperature should be considered in the process of device selection.It mainly introduces the six-way measuring bridges of tension,bending moment,torque and temperature,the amplification circuit of small signal,the power conversion circuit,and the data acquisition circuit,storage circuit,communication circuit and voltage controlled by the microprocessor chip SM470R1B1 M.compensation circuit.