Analysis of influencing factors on suction capacity in seabed natural gas hydrate by cutter-suction exploitation

Abstract

The mathematical and simulation models of working head in the deep-sea working environment were built to analyze the effects of cutter-suction flow, cutter-head rotating speed, cutting depth and suction port position on the cutter-suction capacity. The efficiency of the cutter-suction is analyzed based on the analysis of the variation law of the solid-phase volume fraction of the flow field, the variation law of the velocity distribution in the flow field and the distribution law of the solid-phase concentration. The results show that the increase of cutter-suction flow can significantly improve the cutter-suction efficiency when it is less than 1000 m³/h. However, when it is more than 1000 m³/h, it is helpless. When the cutter-head rotate speed is within the range of 10–25 r/min, the cutter-suction efficiency stabilizes at about 95%. While the speed is greater than 25 r/min, the cutter-suction efficiency decreases sharply with the increase of cutter-head rotate speed. With the increase of cutting depth, the cutter-suction efficiency first increases and then remains stable and finally decreases. The cutter-suction efficiency remains at about 94% when the suction port position deviation ranges from 0° to 30°, but it has a sharply reduction when the deviation angle is more than 30°.

Keywords

seabed natural gas hydrate / working head / solid-liquid two-phase flow / cutter-suction capacity / influencing factor

References

[1] MakogonY F, HolditchS A, MakogonT Y. Natural gas-hydrates—A potential energy source for the 21st Century [J]. Journal of Petroleum Science & Engineering, 2007, 56(1–3): 14-31

[2] BoswellR, CollettT S. Current perspectives on gas hydrate resources [J]. Energy & Environmental Science, 2011, 4(4): 1206-1215

[3] TianGong. New sources of energy after shale gas—natural gas hydrate [J]. Natural Gas Industry, 2016, 36(5): 24

[4] LiPengStudy on hydraulic lifting law of coarse grain vertical pipe [D], 2007, Beijing, Tsinghua University

[5] YoonC H, ParkJ M, KangJ S. Shallow lifting test for the development of deep ocean mineral resources in Korea [C]//Proceedings of the 9th ISOPE Ocean Mining Symposium. Hawaii: International Society of Offshore and Polar Engineers, 2011, 145149-152

[6] ParkS J, YeuT K, HongS, ChoiJ S, KimhWDesign of a Hardware-in-the-loop Simulation (HILS) of control and monitoring system for deep-seabed manganese nodule miner [C]//Proceedings of the 7th ISOPE Ocean Mining Symposium, 2007, Portugal, Lisbon

[7] ZhuC, ZhangM, LiuX. Gas hydrates: Production, Geohazards and Monitoring [J]. Journal of Catastrophology, 2017, 32(3): 51-56

[8] LiuYi. The perspective of natural gas industry chain overall planning in 12th five-year [J]. Natural Gas Industry, 2013, 33(2): 105-109

[9] ZhouS, ChenW, LiQ, ZhouJ, ShiHe. Research on the solid Fluidization well testing and production for shallow non-diagenetic natural gas hydrate in deep waterarea [J]. China Offshore Oil and Gas, 2017, 29(4): 1-8

[10] SongY, YangL, ZhaoJia. The status of natural gas hydrate research in China: A review [J]. Renewable & Sustainable Energy Reviews, 2014, 31(2): 778-791

[11] XuH, YangF, WuBoA method of submarine natural gas hydrate cutter-suction: China, 2015201509

[12] XuH, LinL, WuW, WuBo. Research on cutter-suction mining method for submarine natural gas hydrate [J]. Acta Scientiarum Naturalium Universitatis Sunyatseni, 2011, 50(3): 48-52

[13] LiL, XuH, YangFang. Three-phase flow of submarine gas hydrate pipe transport [J]. Journal of Central South University, 2015, 22(9): 3650-3656

[14] ChenXiaoAnalysis of rock cutting for large-sized cutter suction dredger [D], 2012, Shanghai, Shanghai Jiao Tong University

[15] LingLiang. Analysis on cutting forces and influence factors of the suction dredger’s cutter [J]. Ship & Ocean Engineering, 2014, 43(4): 156-159

[16] ZhangDeCutting force calculation based on 2-D soild-cutting theory and stress analysis of cutterhead by ANSYS [D], 2007, Nanjing, Hohai University

[17] WuK, JiaT, LianD, YanC, DaiMao. Research on design of mining tools of marine gas hydrate reservoirs [J]. Mechanical Science and Technology for Aerospace Engineering, 2017, 36(2): 225-231

[18] DekkerM A, KruytN P, BurgerM D, VlasblomW J. Experimental and numerical investigation of cutter head dredging flows [J]. Journal of Waterway, Port, Coastal and Ocean Engineering, 2003, 129(5): 203-209

[19] LiuY, ZhuH, WuY, ZhengLiang. Numerical simulation of influencing factors on sediment intake of cutter suction dredger [J]. Ship & Ocean Engineering, 2016, 45(4): 166-169

[20] FangY, NiFu. Numerical simulation of 2-D water flow in and around cutter of a dredger [J]. China Harbour Engineering, 2011, 23(2): 4-7

[21] WeiX, ZhangY, FanS, XiongTing. The efficiency optimization of cutter suction dredger’s suction system based on differential envolution [J]. Ship & Ocean Engineering, 2017, 46(2): 143-147

[22] PadsalgikarA. Particle transport in stratified gas-liquid-solid flow [D]. Gradworks, 2015

[23] LiuJ, ShaoZ, ZhengYong. Numerical simulation of the decomposition of natural gas hydrates by depressurization [J]. Journal of Southwest Petroleum University (Science & Technology Edition), 2017, 39(1): 80-90

[24] ChengX R, LiR N, GaoY, GuoW L. Numerical research on the effects of impeller pump-out vanes on axial force in a solid-liquid screw centrifugal pump [J]. Iop Conference Series: Materials Science & Engineering, 2013, 33(1): 257-260

[25] ChengX R, ZhangN, ZhaoW. Pressure fluctuation features of sand particle-laden water flow in volute of double-suction centrifugal pump [J]. Journal of Drainage and Irrigation Machinery Engineering, 2015, 33(1): 37-42

[26] RichardsP J, HoxeyR P. Appropriate boundary conditions for computational wind engineering models using the k-ϵ turbulence model [J]. Journal of Wind Engineering & Industrial Aerodynamics, 1993, 47(93): 145-153

[27] LuB, LiG, SunD, HuangS, ZhangFu. Acoustie-physical properties of seafloor sediments from nearshore southeast China and their correlations [J]. Journal of Tropical Oceanography, 2006, 25(2): 12-17