Study On Layout Scheme Of Distributed Optical Fiber Sensing System For Submarine Pipeline

With the development of global economy, the demand of energy sources grows day and day. Submarine pipeline is one of the most important manners for offshore oil and gas transportation, as it works in formidable natural conditions, the inactivation accidents happen sometimes. Not only the accidents of submarine pipeline have effect on regular production of offshore oil and gas field, but also the leakiness of oil and gas pollute ocean environment badly, and the accidents will make huge economic losses and adverse society influence. Therefore, effective measures must be adopted to prevent the inactivation accidents of submarine pipeline.In recent years, distributed optical fiber sensing technology has been applied more and more widely in structural health monitoring because of many advantages. In order to apply it to submarine pipeline, a subject named "Distributed Optical Fiber Sensing Technology for Long Distance Submarine Pipeline" which is sponsored by Hi-Tech Research and Development Program of China ( 863 ) has undertaken by Zhejiang University, to monitor the healthy state of submarine pipeline through building distributed optical fiber sensor system. Based on this subject, some research has been performed in this paper. Under the background of laying B-DOFS system on submarine pipeline of QK17-2 oil field, complete and feasible offshore construction scheme has been designed to lay the monitoring system on submarine pipeline safely and availably, and it can ensure the system enough reliably during the working period.On the basis of analyzing disadvantages of present inspection techniques and problems on distributed optical fiber sensing technology for submarine pipeline, aiming the difficulty in project application, the preliminary plan of adopting air-blow method in internal pipe and glue connection method on external pipe has been putted forward. Through air-blow performance experiment, mixture proportion test of grouting material and vacuum grouting test for long distance microtubule, the model of optical fiber and microtubule has been selected, the grouting material has been compounded, the construction technology of air-blow and vacuum grouting has beenconsummated, and the aim of air-blow optical fiber and vacuum grouting in microtubule exceeding 500m one-time has come true. Finally, complete and feasible layout scheme of distributed optical fiber sensing system for submarine pipeline has been designed and applied in actual project, and the economy feasibility of this scheme has been analyzed.Optical fiber sensing technology is the developing direction for health monitoring in the future. The research in this project aims at submarine pipeline, but the applicability of the technology is not only localized in submarine pipeline, it can also apply in health monitoring for urban tap water pipeline, gas pipe, bridge and dam, etc. The development potential of optical fiber sensing technology is very well.This research work is sponsored by Hi-Tech Research and Development Program of China ( 863 ) ( Grant No. 2004AA602210-1 and 2001AA602022-1 ) .