Marine Steel Riser's Life Extension Technology Research Based On Non-Leaking Damage

With offshore oil and gas exploration to deep sea in the worldwide, deep sea engineering structure of service safety in extreme environment gets more and more attention, marine riser is an important part of platform system, How to realize to extend its service life is still a challenging problem for the development of offshore oil and gas resources. Compared with the onshore oil and gas pipelines, bearing characteristics, installation method, the inspection and maintenance technology and many other aspects of marine riser are quite different, sometimes, the new design concept, analysis method and the test technology etc. is needed. Although our country scholars and researchers have conducted many studies on offshore platform and system components, but it has not yet been made on the analysis of life extension technology of the damaged riser. Based on material the life extension idea which was proposed by some academicians such as Shi Changxu, Gan Yong,Zhou Lian etc. Life extension technology of marine steel riser mainly includes the composite repair technology of damaged riser and integrity management technology of marine riser. The main aims is to discuss the application research aspect of making composite to repair damage marine steel riser, and to promote the marine riser integrity management technology continues to improve.The purpose of this paper is to discuss feasibility of applying the technology of composite repair terrestrial pipeline to repair the marine riser by means of the comprehensive analysis and experimental study. At the same time, integrity management technology for marine risers are discussed and analyzed, non-leaking damage remaining strength assessment method and quantitative risk analysis method are established. First of all, at the part of life extension technology of composite repair steel riser, the typical case of marine riser under the independent or combined effects of internal pressure, tensile and bending is considered. Experimental evaluation of the traditional composite repair systems currently exist, the traditional type of composite repair systems at present are assessed through the experiment, on the basis of the work, system of novel carbon based composite material is developed, And geometry is optimized by mechanical analysis, numerical simulation and prototype testing in order to obtain a good reinforcement of repair system:hybrid carbon/glass fiber. Secondly, at part of life extension technology of the riser integrity management, riser strength design method based on reliability, non-leaking damage concept is proposed, residual strength assessment method of the corrosion and mechanical damage riser was initially established, and quantitative risk analysis is applied to the marine riser.In this paper, the material life extension concept is applied to the field of marine riser for the first time, and the steel riser life extension technology is divided into composite repair technology and Integrity management technology. At the same time, the concept of non-leaking damage was proposed, the corrosion damage and mechanical damage uniform classified as non-leaking injury. Combined with the typical mechanical analysis, finite element numerical simulation and full-scale test, state evaluation was used to the corrosion steel riser sample of using composite repair, and the carbon/glass fiber system after optimization are analyzed and tested. Composite repair technology as a feasible riser life extension technology is proved; the new type of CRA repair system has a good repair effect. Riser strength design method of based on reliability was initially established, and it is applied to residual strength assessment of non-leaking injury, at the same time, risk quantification analysis of riser are usedIn this paper, when it is to confirm prospective position of material life extension concept in marine riser, through the analysis and research on the composite repair technology and integrity management technology, the theoretical foundation and experimental results for riser composite repair technology is established, it also provides reference method and constructive guidance for marine steel riser material life extension.