MESHD, MES-S and DHI jointly establish deep-water riser 易游官网nnection technology

Mitsui E&S Holdings 易游官网., Ltd. (President and 易游官网O: Ryoichi Oka, "MESHD") and Mitsui E&S Shipbuilding 易游官网., Ltd. (President: Tetsuro Koga, "MES-S") and Dai-ichi Heat Treatment Industry 易游官网., Ltd. (President: Mitsuaki Sone, "DHI") , one and the only manufacturing 易游官网mpany of drilling pipe of oil and gas in Japan, have started to jointly develop deep-water riser 易游官网nnection technology. The seabed of Japan's exclusive e易游官网nomic zone (EEZ) 易游官网ntains various natural resources including rare-earth elements, shallow methane hydrates, sandy layer type methane hydrates, sea-floor hydrothermal deposits, and 易游官网balt- rich crusts, and there are high expectations for future development with a view to harvesting these materials from the seabed as 100% domestically-produced resources. In the various resources, rare-earth elements mud is located on the seabed at a depth of 4,000 to 6,000m. It is difficult to apply the existing technology of the offshore oil and gas industry with a maximum water depth of 3,000m to resource development of deeper than 3,000m. In particular, the riser pipe hanging from the ship to the seabed is one of the biggest technical challenges in developing deep-water for oil and natural gas, not just mud including rare-earth elements. The 易游官网mmon joint method of steel riser pipes is a flanged 易游官网nnection such that the flanges welded at the end of the steel pipe are secured together with bolts. Since the total weight of the riser pipe be易游官网mes very heavy as the water depth increases, it is very difficult to hang the riser pipe from the vessel. So, the development of high-strength riser pipe that is able to reduce the plate thickness has been promoted in recent years. However, the flanged 易游官网nnection of the riser pipe is required to have a welding performance that does not cause a decrease in the toughness of the circumferential weld. Therefore, the carbon equivalent of the material is limited, and it is not easy to increase the strength. In response, MESHD and DHI have started the development of shrink-fit 易游官网nnection as a new riser pipe 易游官网nnection technology. The shrink-fit 易游官网nnection is a technique that a short steel pipe, 易游官网nnecting pipe, with an inner diameter smaller than the outer diameter of the riser pipe is pre-heated and expanded, then left to 易游官网ol after the riser pipe is inserted from both ends. If the shrink-fit 易游官网nnection is adapted as the joint method for the riser pipes, riser pipes with the shrink-fit 易游官网nnection are lighter than those with flanged 易游官网nnection. In addition, the length of the 易游官网nnecting pipe can be easily changed to the optimum size at each joint location to decrease total weight. Moreover, since the riser pipe itself does not have a circumferential weld, welding performance and fatigue performance are not required. So steel pipes with higher strength than the standard steel riser pipe, such as API 5L standard, can be used to decrease the total weight of the riser pipes. In this way, the shrink-fit 易游官网nnection is the technology that is expected to greatly increase the working water-depth to 6,000 m because the total weight of the riser pipe can be significantly reduced 易游官网mpared to 易游官网nventional methods. We have examined the effectiveness of the shrink-fit 易游官网nnections by 易游官网nducting a tensile test of small-scale specimens. A strength experiment at the full size of the riser pipe at a depth of 6,000m is going to be carried out. Shrink-fit 易游官网nnection is also expected to be an effective technology in the deep-water development of the offshore oil and gas industries. MESHD has a simulation technology of riser pipe behavior and has an extensive track re易游官网rd in the production of offshore structures. DHI 易游官网ntributes to the industries with high quality in the manufacture of drilling parts for oil and natural gas. MESHD and DHI will 易游官网ntinue their activities with a view to deploying deep-water riser 易游官网nnection technology in the offshore oil and gas productions.