| Scientific drilling provides unprecedented opportunities to observe data and test key hypotheses for earth science research,and is the most direct and effective way for mankind to obtain information from the earth's interior at present.Turbodrill is one of the key technical equipment for deep and ultra deep hole drilling.Compared with similar foreign products,the overall level of turbodrills in China has a certain gap in both technical performance and service life,and the design and processing of small-diameter turbodrills are still in the initial state.Introducing and researching foreign small diameter turbodrill drilling technology will not only provide the scientific decision-making confidence and basis for our country's ultra-deep drilling of ten thousand meters,deep oil and gas fields and exploration and development of geothermal field,research and exploration of hot dry rock resources which have far-reaching influences on the basic sciences and sustainable development in China,and will also play an important role in promoting independent research and development and improving the comprehensive level of turbine drill design,manufacturing and application in China.In order to explore the scientific operating rules of turbine core drilling,and to make technical reserves for further research on the acquisition of various drilling tools conditions in well and the remote transmission of signals,the acquisition and analysis system for the condition of turbine drilling bottom was trial-produced in the "Research and Application of High-temperature Downhole Dynamic Coring Drilling System for Geological Exploration".The core technology of the system is the downhole acquisition,storage and surface playback of the pressure drop,axial pressure,output torque,output speed and temperature of the turbine drill,as well as the designs for the conditions of vibration,high temperature and high pressure,and the analysis software of the turbine drilling condition was developed.First of all,this paper summarized the purpose,significance and development history of several scientific drilling engineerings at home and abroad in recent years,and elaborated the characteristics and difficulties of scientific drilling construction,which leads to the urgency of research on high-temperature bottomhole dynamic coring drilling system.In addition,the turbodrill drilling technology used to solve the problems of low rock-breaking efficiency in the deep drilling process was summarized,and the requirements for acquiring the operating parameters of the downhole turbodrill in Well Songke-2 were put forward.Then,the research status and development trend of measurement while drilling and downhole engineering parameter detection technology at home and abroad were summarized respectively,and the research methods and ideas of acquisition and analysis system for bottomhole turbodrill working condition in scientific drilling were clarified.Secondly,it introduces the basic information of Well Songke-2,including well location selection,formation conditions,well structure,as well as the technical performance parameters,structure and working principle of the bottomhole turbodrill used.According to the requirements and characteristics of complex environment such as high temperature,high pressure and strong vibration,the overall design of the principle of the detection system was made.The engineering parameters needed to be tested for turbodrill working condition analysis were defined,and the detection methods of speed,pressure,torque,axial compression and temperature were designed.The rotational speed was obtained indirectly by calculating the centrifugal force with the accelerometer.Drilling fluid pressure was obtained through a special pressure sensor.Torque and axial compression were obtained by full bridge strain gage combination.Temperature was obtained by thermal resistance detection.Thirdly,the downhole detection sub was designed,including the installation position of the detection sub and the design of a new mechanical structure suitable for the reasonable arrangement of each detection sensor.Both theoretical calculation and software simulation were used for checking the mechanical strength of the designed joint.Because the sub will run into the bottom of the well with the drilling tool,it will face the harsh environment,so it is necessary to design the sealing and pressure resisting structure of the sub and carry out several rounds of testing.The new circumferential three-cavity structure,inner and outer cylinder thread connection,conical sealing surface and 6 high-temperature resistant fluorine rubber O-ring seals were adopted to meet the requirements of complex underground conditions.In the fourth chapter,the detection circuit was designed,focusing on the optimization of the high-temperature resistant components of the detection circuit,acquisition plate and strain gauge adhesive.A complete set of electronic measuring system suitable for deep drilling engineering is formed by the combined methods of high temperature resistant centrifugal accelerometer for measuring speed,high temperature resistant strain sensor and operational amplifier,and high temperature resistant microprocessor and memory chip.In the fifth chapter,the surface analysis system is designed.By playing back the data collected by the downhole sub,the theoretical calculation model of the working condition analysis software of the turbine drill was established according to the torqueaxial compression coupling analysis,the modeling of the temperature field distribution of circulating well slurry with large temperature difference and the new frictional calculation analysis of the drilling fluid's pressure.According to the difference between the measured data of the acquisition module in the hole and the theoretical calculated data,the error of the theoretical model was compared and corrected,and the influence of multiple factors on the output characteristics of the turbine drill was analyzed.The theoretical calculation model of coupling and inversion analysis of multi-measurement parameters was established to provide a basis for optimizing surface parameters and maintaining and adjusting drilling fluid system in the future.The sixth chapter introduces the laboratory test and field application of the testing system.The laboratory test includes torque and speed test,axial compression and pressure test,temperature and anti-vibration test,and sealing performance test.Through repeated tests,it is ensured that the detection sub can work normally for more than 36 hours continuously in the high temperature and high pressure environment of no less than 175? and 80 MPa in the Well Songke-2.Some test results are obtained by field calibration and instrument connection installation.To sum up,this paper focuses on acquisition and analysis system for working condition of turbodrill in deep drilling downhole,and has carried out a series of theory and practice research.It is a combination of multi-disciplinary theory and technology,and a typical interdisciplinary application of relevant theoretical research.The experimental results proved that the system has basically met the expected design requirements.It provides technical support for the follow-up research on acquisition and signal remote transmission of drilling tool's condition downhole,development of turbine bottom drive of high speed drilling coring drilling system.At the same time,there are still more research needs to be in the follow-up work for further exploring. |
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