| DGD(dual gradient drilling)resolved the high risk and negative economic issues compared with the conventional drilling in deep water drilling process.Among the DGD methods,the EC-Drill technology based on the drilling method without risers was extensively applied in engineering and gained significant economic and environmental benefits.This work focuses on the power transmission unit and control unit of EC-Drill in DGD drilling.(1)The scheme of EC-Drill technologyConsidering the operational environment over 500-1500 m deep water in China and the advanced foreign technology,the EC-Drill scheme for both shallow water and the deep water was proposed which includes the introduction of the scheme,study on critical equipment and operational process and the analysis on technology characteristics.The systems elements,operation procedure and the characters of well control operations in EC-Drill were studied.(2)The design of the power transmission system in EC-Drill technologyThe scheme of the power transmission system in EC-Drill technology was designed according to the principal of power transmission system design.The output power of the power transmission system in EC-Drill technology was obtained by calculating the location of the lift pump arrays below the sea bed based on the hydraulics theories.The communication system was designed upon the equipment of the drive transmission system and the operational environment.(3)The design of the experimental platform in EC-Drill systemThe experimental platform of EC-Drill system was established by improving the SMD experimental platform.The anti-jamming system was designed considering the operational environment,which on the foundation of the SMD experimental platform.The data acquisition and storage unit,serial communication unit and control unit of the experimental platform were developed on LabVIEW software.Experiments were conducted to test the operation conditions and the efficiency of the control results.(4)The design of the controller in EC-Drill systemThe low order mathematic model of EC-Drill system was constructed by law of conservation of mass and law of conservation of momentum.The minimum order observer of observation-state feedback controller was designed through the modern control theory which transferred the math modelling to state-space equations.The control effect was reflected by the simulation analysis on the controller. |
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