Development and Use of a Downhole System for Measuring Drilling Engineering Parameters

A system capable of operating in downhole conditions at depths of several thousand meters is developed for measuring drilling engineering parameters (DEP) in real time. The aim is to monitor DEP during drilling, including the weight on the drill bit (WOB), torque on the drill bit (TOB), and lateral force on the drill bit. The design of the structure and parameters of the sensors, calibration of the sensors, and the field test results are described. Four separate strain gages and a measuring system are designed to measure DEP in the downhole during drilling in real time. The field tests show that the designs are sound. The measured axial force is greater than the calculated value, which means that the real WOB is higher than the logging WOB and the real TOB is greater than the logging torque. Thus, the survey instruments can meet the requirements for rotary steerable drilling and conventional drilling. The measured WOB and TOB data can also be used to analyze drill string vibrations.