Research On Deepwater Key Technology And Experimental Study Of Pipeline Multifunctional Maintaining Tool

Submarine oil pipeline is an important component of the subsea oil exploitation system.Due to the complexity of the seabed environment,the oil pipeline would be broken and should be maintained in time to minimize the economic loss.In our country,the repair technology of oil pipeline is in the initial stage.In order to promote the development of pipeline repair technology,based on the study of pipeline multifunctional maintaining tool–onshore prototype,the deepwater key technology involved in multifunctional maintaining tool is studied and the deepwater part is designed.Finally,the corresponding experiments are conducted to validate the results.In this paper,based on the study of onshore prototype and the Ekman theory,the analysis and calculation of the ocean force of pipeline multifunctional maintaining tool in the deployment process is completed and the requirements of buoyancy system are put forward.The change of buoyancy of pipeline multifunctional maintaining tool is analyzed from three aspects of temperature,pressure and salinity.The value of buoyancy change is provided for the design of buoyancy system,and the general formula of buoyancy variation of underwater operating tool is deduced.Based on the static stability and the design requirements of the buoyancy system of pipeline multifunctional maintaining tool,the general adjustment formula of the buoyancy system of underwater operating tool is deduced.The underwater operations of pipeline multifunctional maintaining tool are divided into initial clamping state,tool operating state and crawling adjustment state.The states of maintaining tool are analyzed and simulated with ADAMS software.Through the simulation,the coordinate changes of the center of the front plate of the front clamping mechanism is obtained,and the dynamic stability of the maintaining tool is studied.Aiming at the requirement of deepwater hydraulic system for underwater operating tool and deepwater operating condition of maintaining tool,the key technology of deepwater hydraulic system for maintaining tool is studied.The design of deepwater hydraulic integrated system with compensation,the research of static and dynamic characteristics of pressure compensator and the dynamic analysis of clamping circuit are accomplished.The results ofAMESim software show that the pressure fluctuation and clamping pressure performance could meet the work requirements.In this paper,the experiments of deepwater hydraulic system are carried out.The correctness and rationality of deepwater hydraulic integrated system with compensation are verified by experiments.The performance of pressure compensator is tested and compared with the simulation result,and the expected effect is achieved.The performance of the clamping circuit is tested to verify the reliability of circuit.In this paper,the analysis,simulation and experimental research on deepwater key technologies of pipeline multifunctional maintaining tool and the mechanics analysis and stability simulation of maintaining tool for underwater operating conditions lay the theoretical foundation,which provides guidance for the design and reconstruction of pipeline multifunctional maintaining tool.