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1.
Natural gas hydrates (NGHs) are globally recognized as an important type of strategic alternative energy due to their high combustion efficiency, cleanness, and large amounts of resources. The NGHs reservoirs in the South China Sea (SCS) mainly consist of clayey silts. NGHs reservoirs of this type boast the largest distribution range and the highest percentage of resources among NGHs reservoirs in the world. However, they are more difficult to exploit than sandy reservoirs. The China Geological Survey successfully carried out two NGHs production tests in the Shenhu Area in the northern SCS in 2017 and 2020, setting multiple world records, such as the longest gas production time, the highest total gas production, and the highest average daily gas production, as well as achieving a series of innovative theoretical results. As suggested by the in-depth research on the two production tests, key factors that restrict the gas production efficiency of hydrate dissociation include reservoir structure characterization, hydrate phase transition, multiphase seepage and permeability enhancement, and the simulation and regulation of production capacity, among which the hydrate phase transition and seepage mechanism are crucial. Study results reveal that the hydrate phase transition in the SCS is characterized by low dissociation temperature, is prone to produce secondary hydrates in the reservoirs, and is a complex process under the combined effects of the seepage, stress, temperature, and chemical fields. The multiphase seepage is controlled by multiple factors such as the physical properties of unconsolidated reservoirs, the hydrate phase transition, and exploitation methods and is characterized by strong methane adsorption, abrupt changes in absolute permeability, and the weak flow capacity of gas. To ensure the long-term, stable, and efficient NGHs exploitation in the SCS, it is necessary to further enhance the reservoir seepage capacity and increase gas production through secondary reservoir stimulation based on initial reservoir stimulation. With the constant progress in the NGHs industrialization, great efforts should be made to tackle the difficulties, such as determining the micro-change in temperature and pressure, the response mechanisms of material-energy exchange, the methods for efficient NGHs dissociation, and the boundary conditions for the formation of secondary hydrates in the large-scale, long-term gas production.©2022 China Geology Editorial Office. 相似文献
2.
【研究目的】中国地质调查局先后于2017年、2020年在南海北部神狐海域成功实施两轮水合物试采,创造了产气时间最长、产气总量最大、日均产气量最高等多项世界纪录,了解和掌握南海天然气水合物开采储层相变与渗流机理,有助于进一步揭示该类型水合物分解机理、产出规律、增产机制等,可为中国海域水合物资源规模高效开采提供理论基础。【研究方法】基于两轮试采实践,笔者通过深入研究发现,储层结构表征、水合物相变、多相渗流与增渗、产能模拟与调控是制约水合物分解产气效率的重要因素。【研究结果】研究表明,南海水合物相变具有分解温度低,易在储层内形成二次水合物等特点,是由渗流场-应力场-温度场-化学场共同作用的复杂系统;多相渗流作用主要受控于未固结储层的物性特征、水合物相变、开采方式等多元因素影响,具有较强的甲烷吸附性、绝对渗透率易突变、气相流动能力弱等特点;围绕南海水合物长期、稳定、高效开采目标,需要在初始储层改造基础上,通过实施储层二次改造,进一步优化提高储层渗流能力,实现增渗扩产目的。【结论】随着天然气水合物产业化进程不断向前推进,还需要着力解决大规模长时间产气过程中温度压力微观变化及物质能源交换响应机制以及水合物高效分解、二次生成边界条件等难题。创新点：南海水合物相变是由渗流场-应力场-温度场-化学场共同作用的复杂系统;南海泥质粉砂储层具有较强的甲烷吸附性、绝对渗透率易突变、气相流动能力弱等特点,多相渗流机理复杂。 相似文献
3.
叶建良 秦绪文 谢文卫 卢海龙 马宝金 邱海峻 梁金强 陆敬安 匡增桂 陆程 梁前勇 魏士鹏 于彦江 刘春生 李彬 申凯翔 史浩贤 卢秋平 李晶 寇贝贝 宋刚 李博 张贺恩 陆红锋 马超 董一飞 边航 《中国地质》2020,47(3):557-568
泥质粉砂型天然气水合物被认为是储量最大开采难度亦最大的水合物储层,2017年南海天然气水合物试采,初步验证了此类水合物储层具备可开采性。在总结前次试采认识的基础上,对试采矿体进行优选、精细评价、数值与试验模拟和陆地试验,中国地质调查局于2019年10月—2020年4月在南海水深1225 m神狐海域进行了第二次天然气水合物试采。本次试采攻克了钻井井口稳定性、水平井定向钻进、储层增产改造与防砂、精准降压等一系列深水浅软地层水平井技术难题,实现连续产气30 d,总产气量86.14×104m3,日均产气2.87×104m3,是首次试采日产气量的5.57倍,大大提高了日产气量和产气总量。试采监测结果表明,整个试采过程海底、海水及大气甲烷含量无异常。本次成功试采进一步表明,泥质粉砂储层天然气水合物具备可安全高效开采的可行性。 相似文献
4.
继我国在神狐海域两次天然气水合物试采成功之后,近几年来在琼东南盆地的勘探证实了天然气水合物的存在,而且钻探表明其与浅层气具有复杂的共生关系.为揭示琼东南盆地深水区天然气水合物与浅层气共生体系成藏特征,结合岩心、测井及三维地震数据,阐明了天然气水合物与浅层气的空间分布特征,研究结果表明,天然气水合物主要赋存在海底以下200 m范围内的沙质沉积物中,且其形成过程与浅层气的垂向运移有关.对天然气水合物与浅层气共生体系成藏特征的深入分析表明,深部热成因气和浅部生物成因气是其重要的气体来源,第四系未固结沙层是良好的储层,且天然气水合物和浅层气共生体系的分布主要受深部气烟囱和断层的控制.浅层气藏为天然气水合物提供稳定的气源条件;第四系块体流沉积与含天然气水合物地层能有效地封堵浅层气的纵向运移,进一步促进浅层气的成藏.因此,天然气水合物的形成与浅层气的发育具有正反馈的相互作用关系,有利于形成更大规模的天然气水合物矿体和浅层气藏,具有良好的商业开发潜力. 相似文献
5.
中国南海北部陆坡区是天然气水合物成藏的理想场所,资源潜力巨大。文章基于天然气水合物勘探成果,结合南海北部天然气水合物成藏地质背景,从天然气水合物成藏的温压稳定条件、气源形成条件、构造输导条件和沉积储集条件4方面,系统分析了南海北部天然气水合物成藏的基本地质条件,探讨了南海北部陆坡中部神狐海域、南海北部陆坡西部海域和南海北部陆坡东北部海域天然气水合物的成藏类型与成因模式。结果认为,南海北部陆坡中部神狐海域主要发育扩散型水合物,而南海北部陆坡西部海域主要发育渗漏型水合物,南海北部陆坡东北部海域则发育兼具扩散型与渗漏型特征的复合型水合物。 相似文献
6.
深海水合物赋存于一定的温度和压力环境下,降压开采时降压速率对分解产气速率和储层变形特性影响显著。利用浙江大学自主研发的水合物降压开采试验装置,通过伺服控制降压速率,初步开展了水合物储层模型降压开采试验,研究了储层温度场、孔压场、产气量等的响应特性,探讨了降压速率对产气效率和储层变形特性的影响规律。试验表明：水合物竖井降压开采时,开采井周围储层温度率先下降,分解域由井周逐步向周围发展。适当提高降压速率能够提高储层开采效率,但降压速率过快时易导致水合物重生成,反而不利于水合物高效持续稳定开采,开采时应选择合理的降压速率以达到最优产气效率。开采过程中根据储层孔隙与外界连通程度,储层孔隙状态可分为完全封闭型、局部封闭型和开放型3种类型。储层开采试验完成后,浅层土体出现 3 种不同变形特征的区域：I 区为井周土层,呈漏斗型下陷;II 区土层平坦,无明显扰动痕迹;III 区为边界土层,该处水气产出受阻导致部分气体向上迁移引起土丘状隆起带出现。这些变形特征与气体在储层中的迁移路径和运移模式相关。通过相似性分析,给出了模型与原型分解时间和产气量等的对应关系。 相似文献
7.
人为控制性放气是杭州地铁工程施工前防治浅层气地质灾害的必要措施。通过对浅层气藏形成中的水气运移过程分析可知,气藏原始包气带内的水压力和吸力沿厚度呈线性分布,孔隙水压力的大小与其相同位置处的静水压力相当;借助储层土体的室内土-水特征曲线并结合现场勘探资料,能够获得气藏初始饱和度分布。在分析有控放气措施下气藏内部水气运移基础上,利用GDS非饱和应力路径三轴系统地研究了气体释放过程中储气砂土的湿化变形,并给出了气体释放引起的含气地层沉降变形的预测方法。结果表明,在经历了形成过程中的自然脱湿后,储集层砂土被进一步压密,而工程放气措施引起的水浸或再吸湿过程中,单由饱和度或吸力减小所引起的砂土湿化变形量很小,可忽略其工程影响;有控放气措施下,由气体释放引起的浅层含气地层沉降沿气藏厚度自上而下依次递减,总沉降量约为气藏总厚度的1‰～5‰。 相似文献
8.
Yan Li Yun-Xin Fang Qian-Zhi Zhou Xiang-Po Xu Jin-Zhong Liu Guo-Yi Zhou Jiang-Hai Wang 《地学前缘(英文版)》2021,12(6):394-403
Methane hydrate in the South China Sea(SCS)has extensively been considered to be biogenic on the basis of itsδ13C and δD values.Although previous efforts have greatly been made,the contribution of thermogenic oil/gas has still been underestimated.In this study,biomarkers and porewater geochemical parameters in hydrate-free and hydrate-bearing sediments in the Taixinan Basin,the SCS have been measured for evaluating the contribu-tion of petroleum hydrocarbons to the formation of hydrate deposits via a comparative study of their source inputs of organic matters,environmental conditions,and microbial activities.The results reveal the occurrence of C14-C16 branched saturated fatty acids(bSFAs)with relatively high concentrations from sulfate-reducing bacteria(SRBs)in hydrate-bearing sediments in comparison with hydrate-free sediments,which is in accord with the positive δ13C values of dissolved inorganic carbon(DIC),increasing methane concentrations,decreasing alka-linity,and concentration fluctuation of ions(Cl-,Br,SO2-,Ca2+,and Mg2+).These data indicate the relatively active microbial activities in hydrate-bearing sediments and coincident variations of environmental conditions.Carbon isotope compositions of bSFAs(-34.0％o to-21.2％o),n-alkanes(-34.5％o to-29.3％o),and methane(-70.7％o to-69.9％o)jointly demonstrate that SRBs might thrive on a different type of organic carbon rather than methane.Combining with numerous gas/oil reservoirs and hydrocarbon migration channels in the SCS,the occurrence of unresolved complex mixtures(UCMs),odd-even predominance(OEP)values(about 1.0),and biomarker patterns suggest that petroleum hydrocarbons from deep oil/gas reservoirs are the most probable carbon source.Our new results provide significant evidence that the deep oil/gas reservoirs may make a contribution to the formation of methane hydrate deposits in the SCS. 相似文献
9.
With the implementation of the production tests in permafrost and offshore regions in Canada, US, Japan, and China, the study of natural gas hydrate has progressed into the stage of technology development for industrial exploitation. The depressurization method is considered as a better strategy to produce gas from hydrate reservoirs based on production tests and laboratory experiments. Multi-well production is proposed to improve gas production efficiency, to meet the requirement for industrial production. For evaluating the applicability of multi-well production to hydrate exploitation, a 2D model is established, with numerical simulations of the performance of the multi-well pattern carried out. To understand the dissociation behavior of gas hydrate, the pressure and temperature distributions in the hydrate reservoir are specified, and the change in permeability of reservoir sediments is investigated. The results obtained indicate that multi-well production can improve the well connectivity, accelerate hydrate dissociation, enhance gas production rate and reduce water production as compared with single-well production. 相似文献
10.
海洋含水合物地层往往是具有渗透性的多孔介质体,钻井过程中钻井液不可避免地会与它发生能量和物质交换,水基钻井液驱替侵入水合物地层和温差下热传导导致的水合物分解这二者是耦合在一起的,其侵入可描述为一个包含相变的非等温非稳态渗流扩散过程。在综合分析钻井液侵入含水合物地层特性的基础上,结合水合物开采数值模拟以及常规油气藏钻井液侵入模型,建立了一维径向钻井液侵入含水合物地层的侵入模型。利用编程,分析了钻井液侵入水合物地层时地层压力、各相饱和度和温度的分布规律。 相似文献
11.
This study, based on 3.5 kHz SBP, 3D seismic data and long piston cores obtained during MD179 cruise, elucidated the timing and causes of pockmark and submarine canyon formation on the Joetsu Knoll in the eastern margin of the Sea of Japan. Gas hydrate mounds and pockmarks aligned parallel to the axis on the top of the Joetsu Knoll are associated with gas chimneys, pull-up structures, faults, and multiple bottom-simulating reflectors (BSRs), suggesting that thermogenic gas migrated upward through gas chimneys and faults from deep hydrocarbon sources and reservoirs. Seismic and core data suggest that submarine canyons on the western slope of the Joetsu Knoll were formed by turbidity currents generated by sand and mud ejection from pockmarks on the knoll. The pockmark and canyon formation probably commenced during the sea-level fall, lasting until transgression stages. Subsequently, hydropressure release during the sea level lowering might have instigated dissociation of the gas hydrate around the base of the gas hydrate, leading to generation and migration of large volumes of methane gas to the seafloor. Accumulation of hydrate caps below mounds eventually caused the collapse of the mounds and the formation of large depressions (pockmarks) along with ejection of sand and mud out of the pockmarks, thereby generating turbidity currents. Prolonged pockmark and submarine canyon activities might have persisted until the transgression stage because of time lags from gas hydrate dissociation around the base of the gas hydrate until upward migration to the seafloor. This study revealed the possibility that submarine canyons were formed by pockmark activities. If that process occurred, it would present important implications for reconstructing the long-term history of shallow gas hydrate activity based on submarine canyon development. 相似文献
12.
LIU Liping SUN Zhilei ZHANG Lei WU Nengyou Yichao Qin JIANG Zuzhou GENG Wei CAO Hong ZHANG Xilin ZHAI Bin XU Cuiling SHEN Zhicong JIA Yonggang 《《地质学报》英文版》2019,93(3):731-755
Natural gas hydrates have been hailed as a new and promising unconventional alternative energy, especially as fossil fuels approach depletion, energy consumption soars, and fossil fuel prices rise, owing to their extensive distribution, abundance, and high fuel efficiency. Gas hydrate reservoirs are similar to a storage cupboard in the global carbon cycle, containing most of the world’s methane and accounting for a third of Earth’s mobile organic carbon. We investigated gas hydrate stability zone burial depths from the viewpoint of conditions associated with stable existence of gas hydrates, such as temperature, pressure, and heat flow, based on related data collected by the global drilling programs. Hydrate-related areas are estimated using various biological, geochemical and geophysical tools. Based on a series of previous investigations, we cover the history and status of gas hydrate exploration in the USA, Japan, South Korea, India, Germany, the polar areas, and China. Then, we review the current techniques for hydrate exploration in a global scale. Additionally, we briefly review existing techniques for recovering methane from gas hydrates, including thermal stimulation, depressurization, chemical injection, and CH4–CO2 exchange, as well as corresponding global field trials in Russia, Japan, United States, Canada and China. In particular, unlike diagenetic gas hydrates in coarse sandy sediments in Japan and gravel sediments in the United States and Canada, most gas hydrates in the northern South China Sea are non-diagenetic and exist in fine-grained sediments with a vein-like morphology. Therefore, especially in terms of the offshore production test in gas hydrate reservoirs in the Shenhu area in the north slope of the South China Sea, Chinese scientists have proposed two unprecedented techniques that have been verified during the field trials: solid fluidization and formation fluid extraction. Herein, we introduce the two production techniques, as well as the so-called “four-in-one” environmental monitoring system employed during the Shenhu production test. Methane is not currently commercially produced from gas hydrates anywhere in the world; therefore, the objective of field trials is to prove whether existing techniques could be applied as feasible and economic production methods for gas hydrates in deep-water sediments and permafrost zones. Before achieving commercial methane recovery from gas hydrates, it should be necessary to measure the geologic properties of gas hydrate reservoirs to optimize and improve existing production techniques. Herein, we propose horizontal wells, multilateral wells, and cluster wells improved by the vertical and individual wells applied during existing field trials. It is noteworthy that relatively pure gas hydrates occur in seafloor mounds, within near-surface sediments, and in gas migration conduits. Their extensive distribution, high saturation, and easy access mean that these types of gas hydrate may attract considerable attention from academia and industry in the future. Herein, we also review the occurrence and development of concentrated shallow hydrate accumulations and briefly introduce exploration and production techniques. In the closing section, we discuss future research needs, key issues, and major challenges related to gas hydrate exploration and production. We believe this review article provides insight on past, present, and future gas hydrate exploration and production to provide guidelines and stimulate new work into the field of gas hydrates. 相似文献
13.
Large borehole with multi-lateral branches: A novel solution for exploitation of clayey silt hydrate
《China Geology》2019,2(3):333-341
ontact area are two main ways to raise the productivity of hydrate. An exploitation technique based on large borehole with multi-lateral branches (LB & MB) was proposed in this paper. This technique is mainly intended for the clayey silt hydrate reservoir in the South China Sea, and its main purpose is to alleviate the sand output from formation for maintaining the stability of the reservoir and to greatly increase the gas productivity of the reservoir. In this paper, the following aspects were mainly expounded: definition of the basic geometric parameters for layout of multi-lateral branches in clayey silt hydrate reservoir, simulation of the stimulation effect of a typical well profile with two branches, and prediction and simulation of the reservoir failure risk in a well profile with eight branches. The results show that the LB & MB effectively improves the flow field in the formation, raises the productivity of the reservoir and may also help to decrease the produced water-gas ratio (WGR). When the lateral branches spacing is too small, the failure zones around adjacent lateral branches overlap each other, possibly causing reservoir failure in a larger range. Therefore, the geometric parameters of multi-lateral branches depend on the dual control of the productivity and geotechnical risk factor of reservoir. Further study is being carried out, so as to obtain the optimal combination of parameters of multi-lateral branches. 相似文献
14.
《China Geology》2018,1(1):5-16
Natural gas hydrates (NGH) is one of key future clean energy resources. Its industrialized development will help remit the huge demand of global natural gas, relieve the increasing pressure of the environment, and play a vital role in the green sustainable growth of human societies. Based on nearly two decades’ studying on the reservoir characteristics in the South China Sea (SCS) and the knowledge of reservoir system, the China Geological Survey (CGS) conducted the first production test on an optimal target selected in Shenhu area SCS in 2017. Guided by the “three-phase control” exploitation theory which focused on formation stabilization, technologies such as formation fluid extraction, well drilling and completing, reservoir stimulating, sand controlling, environmental monitoring, monitoring and preventing of secondary formation of hydrates were applied. The test lasted for 60 days from May 10th when starting to pump, drop pressure and ignite to well killing on July 9th, with gas production of 3.09×105 m3 in total, which is a world record with the longest continuous duration of gas production and maximal gas yield. This successful test brings a significant breakthrough on safety control of NGH production. 相似文献
15.
南海北部陆坡区存在着有利天然气水合物的成藏条件,综合调查及钻探结果揭示南海北部陆坡区蕴藏着丰富的天然气水合物资源,天然气水合物多发育在构造活动复杂地区,同时也是灾害地质因素高发区,潜在的灾害地质因素对水合物的赋存及商业开发是极大的威胁。本文基于广州海洋地质调查局多年来在南海北部天然气水合物发育区采集的大量2D、3D、浅地层剖面及多波束测深资料对南海北部水合物发育区进行海底灾害地质研究,对研究区地形地貌特征、灾害地质因素类型、特征、成因及分布特征进行了综合分析,同时阐述了灾害地质因素与水合物的形成与分解之间的关系,研究结果对南海北部陆坡区天然气水合物区成矿预测、试采井布置及未来灾害风险评价提供了基础数据和决策依据。 相似文献
16.
LI Xiaoyang TIAN Yingying ZHANG Xin SONG Gang ZHAO Ming LIANG Jinqiang HUANG Wei MENG Fanle 《《地质学报》英文版》2022,96(2):701-712
A new gas hydrate reservoir stimulation method of in-situ fracturing with transient heating is proposed, in line with analysis of the technological bottlenecks faced by marine gas hydrate production. This method injects the developed chemical reagents into a hydrate reservoir through hydraulic fracturing, releasing heat during the chemical reaction to increase the hydrate decomposition rate. The chemical reaction product furthermore has a honeycomb structure to support fractures and increase reservoir permeability. Based on the geological model of natural gas hydrate in the South China Sea, three development methods are simulated to evaluate hydrate production capacity, consisting of horizontal well, fractured horizontal well and in-situ fracturing with transient heating well. Compared with the horizontal well, the simulation results show that the cumulative gas production of the fractured horizontal well in one year is 7 times that of the horizontal well, while the cumulative gas production of in-situ fracturing with transient heating well is 12 times that of the horizontal well, which significantly improves daily efficiency and cumulative gas production. In addition, the variation patterns of hydrate saturation and temperature-pressure fields with production time for the three exploitation plans are presented, it being found that three sensitive parameters of fracture conductivity, fracture half-length and fracture number are positively correlated with hydrate production enhancement. Through the simulations, basic data and theoretical support for the optimization of gas hydrate reservoir stimulation scheme has been provided. 相似文献
17.
回顾了25年来国内外水合物开采数值模拟研究的进展,分析了影响水合物开采过程的主要机理,即传热、气液流动和水合物分解。将已有的模型分为热力开采、降压开采和综合3种模型,并对各种模型所具有的特点进行了讨论。综合分析认为,TOUGH Fx/HYDRATE模型充分考虑了多相多组分并借鉴上述3类开采方式,可模拟开采过程中气液流动和相态变化,具有较高的应用价值。最后探讨了目前模型的主要问题以及发展方向,认为水合物矿藏岩石的绝对渗透率、相对渗透率、热传导系数等关键参数的测量及确定是精确模拟水合物开采过程的重要因素。 相似文献
18.
天然气水合物被誉为最有研究价值和开采价值的清洁能源,已经成为当今世界能源研究的热点。但到目前为止还未形成成熟稳定的天然气水合物开采技术体系,仍处于研究和试采阶段。陆域冻土天然气水合物开采与海域天然气水合物开采相比相对比较容易,在钻进过程中能够形成较稳定的孔壁。天然气水合物开采的主要方法有热激法、降压法、置换法和化学抑制剂法。SAGD（Steam Assisted Gravity Drainage）技术也叫蒸汽辅助重力驱油技术,在重油、油砂开采中得到了迅速发展,取得了非常有效的成果,被认为是目前重油开采最有效的方法。对SAGD技术应用到陆域冻土天然气水合物开采中进行理论分析研究,经过分析发现将SAGD技术应用到天然气水合物开采中是可行的,但确定两口水平井之间的距离是关键,且在应用时要将上部井变为生产井,下部井变为注汽井。 相似文献
19.
在陆相断陷盆地中,断裂与砂体是构成油气运移输导网络的主要要素。为了探究断砂组合输导条件控制下的油气运聚规律,本文对歧口凹陷埕北断阶区的断砂组合样式进行了划分,并通过断裂、砂体输导性的定量评价分析了不同样式断砂组合对油气运移成藏的控制作用。结果表明：依据断裂在油气成藏过程中的主要作用不同,划分了油源断裂与多套砂体上下叠置组合、输导断裂与砂体顺向或反向阶梯式组合、调节断裂与砂体"Y"字型组合,共3类4种断砂组合样式,在空间上形成了"接力式"的成藏模式。断砂组合对油气富集的控制作用主要体现在3个方面：①控制了油气藏的类型;油源断裂与多套砂体上下叠置组合主要控制形成岩性-构造、断块类油气藏,输导断裂与砂体顺向或反向阶梯式组合控制形成断块、断鼻和复合类油气藏,调节断裂与砂体"Y"字型组合控制形成断块类油气藏。②控制了油气的运移过程;油源断裂根部与大面积砂体组合沟通深层烃源,在油源断裂活动时,油气先沿断裂运移至浅层,并远距离运移至断阶区高部位富集,输导断裂与砂体顺向或反向阶梯式组合为油气提供阶梯式垂向-侧向运移通道,调节断裂与砂体组合则对油气富集起再调节分配作用。③控制了油气的聚集部位;当断裂输导概率f >50%,砂地比>0.50时,断砂组合起完全输导作用。在中浅层,油气沿输导断裂运移,输导断裂封堵性控制成藏;在中深层,油气富集程度则与砂地比值成正相关。 相似文献
20.
构造控制型天然气水合物矿藏及其特征 总被引：12，自引：4，他引：12
构造环境是天然气水合物富集成藏的重要控制因素,增生楔、断裂体系、褶皱、(泥)底辟、滑塌等特殊构造体是影响天然气水合物成藏的主要地质载体。通过对这些特殊构造体与天然气水合物成藏关系的研究,结合流体活动对水合物形成的影响,总结出陆缘地区有增生楔型、盆缘斜坡型、埋藏背斜型、断褶型、滑塌型及底辟型等六类构造控制型水合物矿藏。南海位于欧亚板块、太平洋板块及印澳板块的交汇处,早期为活动陆缘,晚期演化为被动陆缘,其构造活动具有早期张裂、后期挤压的特点,这既不同于被动陆缘,也有别于活动陆缘,可视为“复合型”大陆边缘,兼具了“被动陆缘沉积速率高、活动陆缘构造活跃”的优点,从而形成了“增生楔型、断褶型、底辟型、滑塌型、盆缘斜坡型”等多种构造控制型水合物矿藏,是“复合型”大陆边缘水合物成藏地质模式的典型代表。 相似文献