Great advancement has been made on natural gas hydrates exploration and test production in the northern South China Sea.However,there remains a lot of key questions yet to be resolved,particularly about the mechanisms...Great advancement has been made on natural gas hydrates exploration and test production in the northern South China Sea.However,there remains a lot of key questions yet to be resolved,particularly about the mechanisms and the controls of gas hydrates enrichment.Numerical simulaution would play signficant role in addressing these questions.This study focused on the gas hydrate exploration in the Shenhu Area,Northern South China Sea.Based on the newly obtained borehole and multichannel reflection seismic data,the authors conducted an integrated 3D basin modeling study on gas hydrate.The results indicate that the Shenhu Area has favorable conditions for gas hydrate accumulation,such as temperature,pressure,hydrocarbon source,and tectonic setting.Gas hydrates are most concentrated in the Late Miocene strata,particularly in the structual highs between the Baiyun Sag and the Liwan Sag,and area to the south of it.It also proved the existence of overpressure in the main sag of source rocks,which was subject to compaction disequilibrium and hydrocarbon generation.It also shown that the regional fault activity is not conducive to gas hydrate accumulation due to excess gas seepage.The authors conjecture that fault activity may slightly weaken overpressure for the positive effect of hydrocarbon expulsion and areas lacking regional fault activity have better potential.展开更多
Upper Gotvand Dam is constructed on the Karun River at the south west of Iran.In this paper,2D and 3D models of the dam together with the foundation and abutments were established,and several seepage analyses were car...Upper Gotvand Dam is constructed on the Karun River at the south west of Iran.In this paper,2D and 3D models of the dam together with the foundation and abutments were established,and several seepage analyses were carried out.Then,the gypsum veins that are scattered throughout the foundation ground were included in the models,and the seepage pattern,considering the dissolution law of gypsum,was analyzed.It was disclosed that the discharge fluxes obtained from 2D and 3D analyses are not similar,and the discharge flux in 3D model is about four times that of the 2D model.Also,the 3D model locates the phreatic surface somewhat higher than the 2D model.This means that the 2D model estimates lower pore water pressure pattern in comparison with the 3D model.These may be attributed to the fact that with 2D model the lateral components of vectors of seepage velocity are ignored.In the current case,the rate of increase of discharge flux due to dissolution of gypsum veins was obtained to be a thirdorder function of the aperture width.In spite of the fact that the grout curtain is designed to be about 170 m deep,however,complete dissolve of gypsum will severely increase the discharge flux through the foundation ground.展开更多
基金funded by Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0201,GML2019ZD0104)Finance Science and Technology Project of Hainan Province(ZDKJ202019).
文摘Great advancement has been made on natural gas hydrates exploration and test production in the northern South China Sea.However,there remains a lot of key questions yet to be resolved,particularly about the mechanisms and the controls of gas hydrates enrichment.Numerical simulaution would play signficant role in addressing these questions.This study focused on the gas hydrate exploration in the Shenhu Area,Northern South China Sea.Based on the newly obtained borehole and multichannel reflection seismic data,the authors conducted an integrated 3D basin modeling study on gas hydrate.The results indicate that the Shenhu Area has favorable conditions for gas hydrate accumulation,such as temperature,pressure,hydrocarbon source,and tectonic setting.Gas hydrates are most concentrated in the Late Miocene strata,particularly in the structual highs between the Baiyun Sag and the Liwan Sag,and area to the south of it.It also proved the existence of overpressure in the main sag of source rocks,which was subject to compaction disequilibrium and hydrocarbon generation.It also shown that the regional fault activity is not conducive to gas hydrate accumulation due to excess gas seepage.The authors conjecture that fault activity may slightly weaken overpressure for the positive effect of hydrocarbon expulsion and areas lacking regional fault activity have better potential.
文摘Upper Gotvand Dam is constructed on the Karun River at the south west of Iran.In this paper,2D and 3D models of the dam together with the foundation and abutments were established,and several seepage analyses were carried out.Then,the gypsum veins that are scattered throughout the foundation ground were included in the models,and the seepage pattern,considering the dissolution law of gypsum,was analyzed.It was disclosed that the discharge fluxes obtained from 2D and 3D analyses are not similar,and the discharge flux in 3D model is about four times that of the 2D model.Also,the 3D model locates the phreatic surface somewhat higher than the 2D model.This means that the 2D model estimates lower pore water pressure pattern in comparison with the 3D model.These may be attributed to the fact that with 2D model the lateral components of vectors of seepage velocity are ignored.In the current case,the rate of increase of discharge flux due to dissolution of gypsum veins was obtained to be a thirdorder function of the aperture width.In spite of the fact that the grout curtain is designed to be about 170 m deep,however,complete dissolve of gypsum will severely increase the discharge flux through the foundation ground.
