Prototype Development And Key Technology Study On Deepwater Pipe Flange Automatic Connection Tool

Along with the gradual reduction of onshore oil reserves, countries all over the world have paid more and more attention to offshore oil exploitation. Meanwhile, the progress of the oil exploitation technology has been promoting the development of the offshore oil exploitation from shallow sea to deep sea regions. Subsea oil pipeline is an important part of construction project of deepwater oil and gas exploitation and the safest, most rapid, most reliable and most economical way of continuous transmission. However, the connecting of deepwater oil pipelines depends on an automation connection machines to connect the oil pipeline. This dissertation is part of the project "Deep sea pipeline technology" sub-project "Deepwater submarine pipeline tie-ins technology and AUT inspection equipment research at home" supported by national 863 hi-tech projects of China. According to the requirements for deepwater pipe connection, applied research on exploitation deepwater pipeline flange automatic connection tool was carried out. Therefore, in order to enhance our country's technology level in the field of offshore oil exploitation and decrease the costs of oil exploitation, it is very important to develop the deepwater subsea pipe automatic connection machine with proprietary intellectual property rights.The development of submarine pipeline connection technology was reviewed in this paper. As a major concern, the recent trend of the deep water pipe flange automatic was emphasized. The advantages and disadvantages of the connection tool were analyzed.The overall design scheme of deepwater pipe flange automatic connection tool was proposed based on the technical requirements of pipe flange automatic connection and the foreign design experience in the field of automatic connection tool and the current technical conditions in China, including the design of mechanical body structure, hydraulic system and control system. The machine structure, including the bolts magazine, nuts magazine, bolt tensile mechanism, was designed using the modular design method. Based on the structural design of machinery, pipe flange automatic connection tool operating procedures was planned.According to the deepwater operational requirements of subsea oil pipe tie-ins, a hydraulic circuit docking device scheme for remotely operated vehicle (ROV) and deepwater pipe flange automatic connection tool was proposed. The study solves the problem of mechanical connection and oil circuit docking for ROV and underwater operation equipment. In order to reduce the positioning accuracy requirements of the early docking, compliant hydraulic connector with adjust dado was designed. The compliant hydraulic connector can compensate the early docking errors, which ensured oil circuit docking precision by the mechanical structure. Based on the probability theory, the probability model of oil docking was established, and the relationship of docking probability and the oil pin tolerance in size and position was gained. The precision of oil pin was calculated by Matlab, the calculation results show the docking probability of the device was high.To solve the problem of 20 bolts synchronous lead-in nuts for deepwater petroleum pipeline flange connection tool, bolts lead-in mechanism was designed according to the operational requirements of deepwater pipeline flange connection tool. By setting the spring, polytetrafluoroethylene(PTFE) jacket and rubber support ring, bolt could be reliable lead-in the nut. For the deepwater environment, the mathematical model of collision that the bolt lead-in the nut was set up. The multi-body dynamic model of bolt lead-in mechanism system was built by ADAMS, and the speed and displacement curve of nut was gained by the study of its operating process dynamic simulation. The results provide basis for actual motion control. The experiment of bolt lead-in mechanism test prototype was performed. The experimental results showed that the bolt could successfully lead-in the nut, verify that the reasonableness of bolt lead-in mechanism design.Using multi-body kinematics theory to homogeneous transformation matrix, the error model of deepwater pipe flange connection tool was established through total differential of the machinery pose transformation matrix. The error model of the tool was calculated by computer simulation, and the effect of the structure parameters on the bolt end pose error was analyzed. Based on the method of error matching design, the error on the deepwater pipe flange automatic connection tool was designed. Considering the specific structure of the connection tool, the adjusting mechanism of bolt angle error was also designed. Therefore, the hardware compensation of bolt angle error was achieved successfully, which improved the positioning accuracy of the bolt end.The performance test of the automatic connection tool was performed in the prototype test platform of deepwater pipe flange automatic connection tool. The motor speed synchronization performance was investigated by the initial fluid resistance test of motor, mechanical friction test of nut wrench and speed synchronous debugging test. The results showed that the design of the nut magazine and the hydraulic control circuit could guarantee synchronous motor speed synchronization error of 20 was 0.0447, which met the flange automatic connection tool operational requirements. Land comprehensive debugging test was carried out, and the results showed that the design of pipe flange connection tool could complete two pipes connection under the remote video monitoring system. The pipe flange automatic connection tool prototype has laid a certain foundation for its engineering application, which has achieved the desired design goals.