| Natural gas hydrate is recognized as one of the important follow-up alternativeenergy with a good prospect by scientists from all over the world. Under specialformation and storage conditions, that is, high pressure with low temperature, theexploration and development technology of natural gas hydrate are different from thatof conventional energy, which is also different in the ocean and land.Drilling sampling is a very important part in the exploration of natural gashydrate, and plays an important role to evaluate accurately for hydrate reserves, whichis the most direct, reliable and effective way to study hydrates. However, formed andexisted in the special environment of high pressure in low temperature caused that thenatural gas hydrate drilling process is different from conventional geological drilling,which should formulate the special drilling regulation accord with the characteristicsof hydrate formation and scientific drilling condition. Therefore, we need to detectaccurately drilling process parameters in the process of scientific drilling, andconclude and summarize the drilling process parameters to got gas hydrate scientificdrilling regulation.In this paper, gas hydrate scientific drilling parameters monitoring system isdeveloped according to the need and law of scientific drilling process of natural gashydrate. The control system of this detection system composes of various sensors andadopts two level distributed control structures; the first level is the upper industrialcontrol, and the second is the down machine.First, the hardware of the system of drilling parameters monitoring is designed.The need to detect of27parameters is determined, they are hole depth, drilling rate,hook load, bit pressure, spindle speed, rotary torque, Mud pump pressure, motorpower, Mud pump flow, circulating mud volume, circulating mud quality changevalue, mud volume,#1box volume,#2box volume,#3box volume, combustiblegas concentration,2#combustible gas concentration, inlet mud temperature, outlet mud temperature, inlet mud cooling temperature, outlet mud cooling temperature,penetration length, drive shaft speed, drilling pressure and hydraulic A, drillingpressure and hydraulic B, motor current and motor voltage.And in view of thedifferent parameters, the sensors are selected, we choose the10kinds of sensor fortesting. The sensors including oil pressure sensor, proximity switch, flow sensor, pullon the rope sensors, current sensors, gas concentration sensor, power transducer,ultrasonic liquid level sensor, temperature sensor, tension sensor. Introducing thevarious sensors, it including measure the parameters, working principle, workingprocess and working methods of the sensors. In addition to we design industrialcomputer hardware, including the main hardware structure, hardware configurationand hardware installation requirements. Because of the system using environmentbadly, we research the system hardware adaptation, in difference temperature、humidness and sunlight, explosion-proof technology, signal anti-jamming technology,conservation technology about power cuts, over-voltage, over-current andunder-voltage，earthquake proofing technique and aseptic technology, and so on.Then we carried out software design for the drilling parameters monitoringsystem. The drilling parameters monitoring system is designed on the basis ofWindows operating system, and developed with the help of Microsoft’s Visual BASICvisual development tools. To complete the final design requirements based on theresearch of six aspects: software architecture of the system, formulation and algorithmrealization of the software, interference filter algorithm of the software, application ofdata stored in the database, software function design, printing software. Systemsoftware include two parts of data acquisition and man-machine interface. Designrequirements for acquisition software: can ensure the acquisition precision, speed, andensure the authenticity, accuracy, reliability of parameters through various numericalcalculation of numerical data acquired; and for man-machine interface: that requirethe interface is simpler, easy to understand, easy setting and can achieve a variety offunctional requirements. Data storage need to be convenient query, playback andprinting.The drilling parameters monitoring system in this paper was designed for MK-2 Scientific Drilling Project to find permafrost gas hydrate. The physical geographycondition, surface surveys and geological condition of MK-2Scientific DrillingProject was also introduced. Project design for MK-2was based on the geologicalstratigraphy, MK-2depth was2300m and the end borehole diameter was77.5mm, thecoring for the whole hole is carried by wire-line coring. As to drilling equipment, weused the HXY-8-type drill rig, SG-24-type derrick, well control system and a series ofits auxiliary equipment. The system composition, working principle and actualapplication result of mud cooling system for gas hydrate core drilling was illustrated.The drilling parameters montoring system used in the MK-2project was especiallyexpatiated, including installation situation on site, service condition and meaningful ofall monitoring parameters.The field test data obtained at MK-2science test well are analyzed by gashydrates drilling parameters monitoring system, including rotate speed, drilling speed,drilling pressure, torque, mud pump, mud pumping pressure, combustible gas contentand mud temperature. And the drilling problems of the various parameters and itsreason are studied. In the process of drilling, the abnormal gas bearing strata arepredicted through the combustible gas detection; the pipe broken accident are avoidthrough the real-time detection of pump pressure; and the relationship betweenformation and rotate speed and drilling pressure are studied by combining statementsand stratigraphic data. Moreover, the mutual influence and the relationship betweeneach parameter are study.The basic evaluation of the parameters monitoring system was given based on itsactual application result in the field, which included well-constructed, fast and rightwhen monitoring and stable and reliable operation. So it can complete the monitoringjob for drilling parameters high quality and efficiency, provide reliable guarantee forScientific Drilling Project. |
PDF Full Text Request