摘要
南海北部天然气水合物勘探与钻探揭示天然气水合物与下伏浅层气具有复杂的共存关系,而天然气水合物与浅层气的共存区是未来非常规资源联合开发的目标。为查明琼东南盆地砂质储层高富集水合物与浅层气有利目标区,结合已有钻探结果及三维地震数据,通过频谱分解-RGB振幅属性融合刻画了砂质储层水合物与浅层气的空间分布特征。研究结果表明,第四纪以来块体搬运沉积体底界海底扇体为良好的富砂质储层,局部位置位于气烟囱构造顶部,受深部高通量流体运聚控制,为高富集水合物的主要目标区。研究区浅层气潜力区主要位于水道末端扇体和水道-天然堤沉积体系,多层浅层气在水合物层下方发育,浅层气藏为上方水合物提供充足的气源条件,同时浅层块体搬运沉积体与含水合物地层为浅层气发育提供良好盖层,因此,琼东南盆地存在水合物与浅层气共存的有利砂质储层勘探靶区。此外,受浅层块体搬运沉积体厚度影响,局部浅层气异常区位于水合物稳定带底界附近,有利于更大规模的水合物成藏,该目标具有良好的商业开发潜力。
Gas hydrate exploration and drilling in the northern slope of the South China Sea have revealed a complex coexistence of gas hydrate and underlying shallow gas reservoirs.This coexistence area presents a promising target for future unconventional resource development and test production.This study aims to identify favorable target areas for high-concentration gas hydrate and shallow gas accumulations in sandrich reservoirs in the Qiongdongnan basin.We use well log data and three-dimensional seismic data to characterize the spatial distribution of these reservoirsby spectral decomposition and RGB color blending techniques.Our findings show that sand-rich reservoirsare predominantly located within submarine fans located at the base of Quaternary mass transport deposits(MTDs).High gas hydrate accumulation sare locally observed at the top of gas chimney structures,which are controlled by high-flux fluid migration from deep sediments.Shallow gas,exhibiting multiplelayers,is trapped at the end of submarine fans and within channel-levee systems beneath the gas hydrate layer.This shallow gas acts as a significant source for overlying gas hydrate accumulation.Conversely,the formation of gas hydrate reduces sediment permeability,hindering upward gas migration and contributing to the enrichment of shallow gas reservoirs.Therefore,the Qiongdongnan basin presents favorable sand reservoir exploration targets characterized by the coexistence of gas hydrate and shallow gas.In addition,due to the changing of thickness of MTDs,local shallow gas anomaly area locate at the base of gas hydrate stability zone,creating conditions conducive to the formation of massive gas hydrate accumulations.This presents a highly promising target for future commercial development and exploration efforts.
作者
周吉林
李丽霞
朱振宇
王秀娟
靳佳澎
王耀葵
张正一
ZHOU Jilin;LI Lixia;ZHU Zhenyu;WANG Xiujuan;JIN Jiapeng;WANG Yaokui;ZHANG Zhengyi(State Key Laboratory of Offshore Natural Gas Hydrates,Beijing 100028,China;Frontiers Science Center for Deep Ocean Multispheres and Earth System,Key Laboratory of Submarine Geosciences and Prospecting Techniques,MOE and College of Marine Geosciences,Ocean University of China,Qingdao,Shandong 266100,China;CNOOC Research Institute Co.,Ltd.,Beijing 100028,China;Deep-sea Multidisciplinary Research Center&Laboratory for Marine Mineral Resources,Laoshan Laboratory,Qingdao,Shandong 266237,China)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2024年第9期2630-2640,共11页
Acta Geologica Sinica
基金
天然气水合物国家重点实验室开放基金(编号2022-KFJJ-SHW)
国家自然科学基金项目(编号42376058,42206063)联合资助的成果。
关键词
天然气水合物
浅层气
砂层
扇体
琼东南盆地
gas hydrate
shallow gas
sand-rich
submarine fan
Qiongdongnan basin
作者简介
周吉林,男,1997年生。博士研究生,从事天然气水合物储层特征研究。E-mail:zhoujilin@stu.ouc.edu.cn;通讯作者:李丽霞,女,1972年生。教授级高工,从事深水沉积与水合物成藏研究。E-mail:lilx@cnooc.com.cn。
