Stability analysis of seabed strata and casing structure during the natural gas hydrates exploitation by depressurization in horizontal wells in South China Sea     

Peng-fei Xie  Lin Yang  Qian-yong Liang  Xu-hui Zhang  Liang-hua Zhang  Bin Zhang  Xiao-bing Lu  Hui-ce He  Xue-min Wu  Yi-fei Dong 《China Geology》2022,5(2):300-309

Natural gas hydrates (NGHs) are a new type of clean energy with great development potential. However, it is urgent to achieve safe and economical NGHs development and utilization. This study established a physical model of the study area using the FLAC^3D software based on the key parameters of the NGHs production test area in the South China Sea, including the depressurization method, and mechanical parameters of strata, NGHs occurrence characteristics, and the technological characteristics of horizontal wells. Moreover, this study explored the law of influences of the NGHs dissociation range on the stability of the overburden strata and the casing structure of a horizontal well. The results are as follows. With the dissociation of NGHs, the overburden strata of the NGHs dissociation zone subsided and formed funnel-shaped zones and then gradually stabilized. However, the upper interface of the NGHs dissociation zone showed significant redistribution and discontinuity of stress. Specifically, distinct stress concentration and corresponding large deformation occurred in the build-up section of the horizontal well, which was thus prone to suffering shear failure. Moreover, apparent end effects occurred at the end of the horizontal well section and might cause the deformation and failure of the casing structure. Therefore, it is necessary to take measures in the build-up section and at the end of the horizontal section of the horizontal well to prevent damage and ensure the wellbore safety in the long-term NGHs exploitation.©2022 China Geology Editorial Office.  相似文献   

An analytical model for evaluating the dynamic response of a tunnel embedded in layered foundation soil with different saturations     

Di  Honggui  Guo  Huiji  Zhou  Shunhua  Wang  Binglong  He  Chao  Zhang  Xiaohui 《地震工程与工程振动(英文版)》2022,21(3):663-681

Earthquake Engineering and Engineering Vibration - This paper proposes an analytical model for evaluating the dynamic response of an underground railway tunnel in layered foundation soil with...  相似文献   

Projection of droughts and their socioeconomic exposures based on terrestrial water storage anomaly over China     

Yin  Jiabo  Guo  Shenglian  Yang  Yan  Chen  Jie  Gu  Lei  Wang  Jun  He  Shaokun  Wu  Boyang  Xiong  Jinghua 《中国科学:地球科学(英文版)》2022,65(9):1772-1787

Science China Earth Sciences - Global warming has altered the thermodynamic and dynamic environments of the climate system, thus affecting the energy budget and water cycle process of the...  相似文献   

南海天然气水合物资源勘查战略接替区初步分析与预测          下载免费PDF全文

何家雄  宁子杰  赵斌  万志峰  孟大江 《地球科学》2022,47(5):1549-1568

二十多年来,南海天然气水合物勘查评价均主要集中在南海北部大陆边缘陆坡深水区,且先后在珠江口盆地神狐、珠江口盆地东部海域调查区和琼东南盆地陵水-松南调查区取得了天然气水合物勘查试采的重大突破及进展,陆续发现了两个大规模的天然气水合物藏,初步评价预测南海天然气水合物资源规模达800亿吨油当量左右,取得了南海天然气水合物勘探的阶段性重大成果.然而,南海天然气水合物资源进一步深化和拓展勘探的有利领域在哪里？尤其是可持续滚动勘探的战略接替区及选区在何处？其与目前陆坡深水油气及水合物勘探紧密相邻的外陆坡-洋陆过渡带（OCT）乃至洋盆区是否具有天然气水合物形成的地质条件？根据海洋地质调查及初步的地质综合分析研究,认为外陆坡-洋陆过渡带乃至洋盆区具备天然气水合物成藏的基本地质条件,可作为南海未来天然气水合物勘查的战略接替区和可持续滚动勘探的战略选区及资源远景区.针对这些影响和决定将来天然气水合物勘探决策部署及走向等关键问题进行初步分析与探讨,抛砖引玉希望能够对未来南海天然气水合物资源勘查评价及战略接替区之选择有所裨益！   相似文献   

川东南盆缘常压区页岩裂缝脉体特征及古压力演化          下载免费PDF全文

曾宇  侯宇光  胡东风  何生  刘若冰  董田  杨锐  李欣诚  叶云飞 《地球科学》2022,47(5):1819-1833

为了查明川东南盆缘常压页岩气区五峰组页岩裂缝脉体记录的古温度及古压力特征,揭示常压页岩气区储层压力降低的主要影响因素和页岩气散失机理.以松坎地区五峰组黑色碳质页岩裂缝脉体内的流体包裹体为主要研究对象,通过显微镜光学观察、阴极发光测试、包裹体测温和激光拉曼分析,结合埋藏-生烃-热史模拟,对裂缝脉体中的气-液两相盐水包裹体和高密度甲烷包裹体进行了系统研究.研究表明:松坎地区五峰组裂缝中主要存在着两期脉体充填,M1裂缝脉体形成时间距今约103~86 Ma,脉体较宽、阴极发光颜色为橘红色,其内甲烷包裹体捕获压力为82.6~91.5 MPa,反映燕山中期盆缘地区页岩气藏处在超压状态;M2裂缝脉体生长于M1裂缝脉体两侧,形成时间距今约90~72 Ma,脉体较窄、阴极发光颜色为暗红色,其内甲烷包裹体捕获压力为43.6~47.3 MPa.综合分析认为,川东南盆缘松坎地区五峰组在燕山期经历了由超压至常压的转变.燕山期以来的抬升剥蚀与褶皱变形导致地层内大量页岩气沿着滑脱层发生侧向运移和散失,地层压力快速下降.燕山晚期时,盆内稳定构造区页岩气藏仍处于超压状态,而盆缘地区已降至常压.   相似文献   

Directional Support Method for Tunnel Jointed Rock Mass     

Wu  Xu  Xu  Jinliang  Zhang  Liyuan  Sun  Jinglai  He  Zhengyu  Gao  Jun 《Geotechnical and Geological Engineering》2022,40(8):4171-4182

Geotechnical and Geological Engineering - In order to explore the directional support method of jointed rock mass and ensure the stable operation of roadway, the support effect of jointed rock mass...  相似文献   

珠Ⅰ坳陷油源对比及恩平组烃源岩的相对贡献          下载免费PDF全文

国朋飞  何生  柴德蓉  殷世艳 《地球科学》2015,40(7):1177-1186

恩平组烃源岩成藏贡献研究对于拓展珠Ⅰ坳陷勘探新领域以及发现新的储量具有重要的应用价值, 目前相关研究较少.在油源对比的基础上, 将生标绝对含量与端元油配比实验相结合, 研究了珠Ⅰ坳陷恩平组烃源岩对单井油样的相对贡献.油源对比结果指示, 研究区原油可分为3类: 第1类源自始新统文昌组中深湖相烃源岩, 主要分布在惠陆低凸起、番禺4洼、流花凸起等地区; 第2类源自始新统-渐新统恩平组湖沼相烃源岩, 仅分布在惠州凹陷北部; 第3类为混源油, 发现于惠州凹陷南部和恩平凹陷.甾萜类绝对含量等7个指标建立的混源比例图版适用于计算油样中前两类烃源岩的相对贡献.计算结果表明, 文昌组烃源岩是珠Ⅰ坳陷的主力烃源岩, 恩平组烃源岩仅对惠州凹陷和恩平凹陷中的部分油样存在贡献.   相似文献   

南天山西段巴雷公花岗岩体的地质年代学及锆石Hf同位素特征——岩石成因及对构造演化的约束     

黄河  王涛  秦切  童英  郭磊  张磊  侯继尧  宋鹏 《岩石矿物学杂志》2015,34(6):971-990

位于中国南天山增生造山带西段的巴雷公岩体的岩石类型为黑云母二长花岗岩。岩体中2件样品的LA-ICP-MS锆石U-Pb年龄为291±3 Ma和283±3 Ma。该岩体具有较高的SiO2(65.88%~72.99%)、K2O(4.23%~6.86%)和全碱含量(K2O+Na2O=7.45%~9.96%),呈现明显的Ba、Nb-Ta、Sr、P和Ti的负异常,以及轻稀土元素相对于重稀土元素的轻-中度富集和明显的Eu负异常(δEu=0.27~0.60)。上述这些特征与A型花岗岩一致。其锆石的εHf(t)值为-4.3~+1.7,二阶段Hf模式年龄为1.20~1.58 Ga。锆石Hf同位素和全岩地球化学特征暗示岩体起源于高温、低压条件下的下地壳中元古代角闪岩相变质基性火成岩的部分熔融。巴雷公岩体的围岩属于代表了南天山洋残迹的蛇绿混杂岩的一部分。巴雷公岩体无变形,侵入至蛇绿混杂岩单元中,具有"钉合岩体"的特点,从而为进一步限定洋盆闭合于二叠纪之前提供了证据。南天山增生造山带二叠纪岩体的Hf同位素均显示古老物源,揭示该增生造山带深部均为古老物质,是塔里木古老基底物质大量卷入的反映。  相似文献   

红格铁矿三维反演与地质建模   总被引：1，自引：0，他引：1  

何敬梓 《地质与勘探》2015,51(6):1049-1058

四川红格钒钛磁铁矿是我国重要的岩浆岩型铁矿石产出基地。在过去几十年中,对红格地区进行了不同程度的勘探,积累了大量地质、物化探资料。但是,这些工作比较分散,不同单位不同时期用多种方法开展了多种比例尺的地质、物化探工作,资料零散的分布于不同单位,没有进行过系统的梳理及研究。本文对红格矿区进行有地质约束的三维磁异常反演,建立了三维地质模型,并实现了三维可视化。分析所建三维地质模型,从宏观上推测了红格铁矿的成矿控矿规律及岩浆运移通道,微观上预测了红格矿区矿体空间位置、形态及控矿、容矿、含矿地质体的分布规律。另外,结合地质模型还进行了找矿潜力评价,分析了矿区外围和深部的找矿前景。  相似文献   

Spatiotemporal variation of meteorological droughts based on the daily comprehensive drought index in the Haihe River basin,China   总被引：4，自引：0，他引：4  

Jun He  Xiao-Hua Yang  Jian-Qiang Li  Ju-Liang Jin  Yi-Ming Wei  Xiao-Juan Chen 《Natural Hazards》2015,75(2):199-217

Meteorological droughts can affect large areas and may have serious environmental, social and economic impacts. These impacts depend on the severity, duration, and spatial extent of the precipitation deficit and the socioeconomic vulnerability of the affected regions. This paper examines the spatiotemporal variation of meteorological droughts in the Haihe River basin. Meteorological droughts events were diagnosed using daily meteorological data from 44 stations by calculating a comprehensive drought index (CI) for the period 1961–2011. Based on the daily CI values of each station over the past 50 years, the drought processes at each station were confirmed, and the severity, duration and frequency of each meteorological drought event were computed and analyzed. The results suggest the following conclusions: (1) the use of the CI index can effectively trace the development of drought and can also identify the duration and severity of each drought event; (2) the average drought duration was 57–85 days in each region of the Haihe River basin, and the region with the highest average values of drought duration and drought severity was Bohai Bay; (3) drought occurred more than 48 times over the study period, which is more than 0.95 times per year over the 50 years studied. The average frequencies of non-drought days, severe drought days and extreme drought days over the study period were 51.2, 3.2 and 0.4 %, respectively. Severe drought events mainly occurred in the south branch of the Hai River, and extreme drought events mainly occurred in the Shandong Peninsula and Bohai Bay; (4) the annual precipitation and potential evapotranspiration of the Haihe River basin show decreasing trends over the past 50 years. The frequency of severe drought and extreme drought events has increased in the past 20 years than during the period 1961–1990. The results of this study may serve as a reference point for decision regarding basin water resources management, ecological recovery and drought hazard vulnerability analysis.  相似文献