Research On The Data Monitoring And Analysis System Of The Downhole Microsphere MWD Instrument

In recent years,with the increasing demand for oil and natural gas resource yet the gradually reducing reserves of conventionally exploitable oil and gas resources,China gradually shift its priority of mining to drilling operations under unconventional complex geological conditions such as deep drills and ultra-deep drills.The development of such complex oil and gas resources is not only difficult to operate,but also lacks effective monitoring methods for wellbore annulus parameters.What's worse,various types of drilling accidents occur frequently,and well control safety faces enormous challenges.The wellbore pressure,temperature and drilling fluid variation parameters are one of the premise and key content of reservoir parameter evaluation and bottom hole working condition judgment,as well as the key to accurately grasp the wellbore flow condition and the safety control of annulus flow.The abnormal changes of various parameters are often the signs of drilling accidents.However,in the mainstream methods of downhole temperature and pressure monitoring in the world,both online monitoring systems and underground storage monitoring systems can only measure the parameter changes of a fixed position.That means the complete full wellbore annulus profile parameters can't be provided;For drilling accidents,it can only be judged by detecting bottom hole pressure,drilling fluid flow rate,drilling fluid density,etc.,which entails hefty hysteresis and has trouble in accurately determining the stratum where the accident occurred.In order to come up with solution to this problem,based on the comprehensive consideration of economic cost and test efficiency,this paper designed and completed a new type of downhole microsphere type while drilling tester data monitoring and analysis system.The system consists of two parts:hardware and master computer software.A new type of downhole microspherical measurement while drilling(MWD)that integrates pressure,temperature,accelerometer and gyroscope and other sensor components with main control circuit and power supply circuit,and a data reading base for realizing data communication betvreen the measuring instrument and the master computer.The software part is adopted.Net architecture and SQL Server database technology,using c#language to write a set of PC software for reading,analyzing and demonstrating data.Firstly,the parameters and errors of the new instrument are set up,and the temperature compensation model is established by fitting the curve with least square method;Then the measurement is put into the drill pipe,and the temperature,pressure,triaxial acceleration,angular velocity and other data in the annulus are collected in real time during the downhole circulation process along with the circulation of drilling fluid.The data are recovered and read after being returned to the ground.Secondly,the master computer corrects the read data according to the established temperature compensation model,and performs data processing by Kalman filtering.Then,according to the inertial navigation theory,the attitude data such as acceleration and angular velocity are obtained by the quaternion attitude calculation and integral calculation.By doing so,the changes of the parameters such as the moving speed,the horizontal swing frequency and the rotation frequency of the measuring instrument in the vertical direction of the wellbore will be obtained.Data such as temperature and pressure are plotted together to form a continuous trend curve of the parameters of the whole wellbore annulus profile,When aceidents sueh as well leakage,overflow and blowout occur in underground,the formation annulus profile parameters measured by the measurement will have corresponding abnormal changes,which can be displayed intuitively on the parameter change trend chart,providing reference for well condition judgment.This technology is an innovative technology for oil drilling condition detection,which provides a new detection method for well control safety and underground accident judgment,and promises broad market prospects.