摘要
基于中国南海北部神狐海域GMGS3钻探区内岩心、测井、二维及三维地震数据综合分析,对黏土质粉砂储集层高饱和度扩散型天然气水合物分布特征、差异聚集机理及其成藏机制进行研究。研究结果表明:高饱和度水合物通常对应着高电阻率、低声波时差,强似海底反射(BSRs),且在BSRs下部可能存在泥底辟及气烟囱等形式的流体渗漏现象;水合物储集层以黏土质粉砂细粒沉积物为主,局部存在具有较高孔渗性的粉砂细粒沉积物;水合物类型以Ⅰ型为主,在Ⅰ型水合物层的底部可能存在Ⅱ型水合物;水合物气源为热解气、微生物气混合成因,来自白云凹陷中心深部的热成因气通过断层和泥底辟及气烟囱向浅层运移并与原位生物气混合,直至运移至水合物温度、压力稳定区域中富集形成高饱和度水合物;流体运移输导系统影响和控制了高饱和度水合物差异聚集成藏。
Based on the comprehensive interpretation of cores, loggings and 2D/3D seismic data of Shenhu GMGS3 drilling area in the northern South China Sea, the distribution characteristics, differential accumulation mechanism and reservoir forming mechanism of diffusion type natural gas hydrate with high saturation discovered from clayey silt reservoirs were investigated. The following findings are reached through the research： （1） Gas hydrate with high saturation often displays high resistivity, low interval transit time, and strong bottom-simulating reflectors （BSRs）, and accompanies with fluid seepage phenomena beneath BSRs, such as mud diapiric structure and gas chimney. （2） The gas hydrate reservoirs are dominated by fine grained clayey silt sediments, and the reservoirs have higher porosity and permeability in local parts. （3） The gas hydrate is largely type I, whereas type II gas hydrate may exist below the type I gas hydrate. （4） The gas sources are mixed microbial and thermogenic gases, and the thermogenic gas originated from the deep formation in the center of Baiyun Sag migrated into shallow strata through faults, mud diapirs and gas chimneys, then was mixed with microbial gas in situ and continued to migrate until they accumulated in the temperature and pressure stability zone and formed diffusion type gas hydrate with high saturation finally. （5） The fluid migration system influenced and controlled the differential distribution of gas hydrate with high saturation.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2017年第5期670-680,共11页
Petroleum Exploration and Development
基金
国家水合物专项项目(GZH201100305)
国家自然科学基金青年科学基金项目(41602149)
关键词
天然气水合物
高饱和度
分布特征
成藏机制
神狐海域
珠江口盆地
南海北部
natural gas hydrate
high saturation
distribution characteristics
accumulation mechanism
Shenhu area
Pearl River Mouth Basin
northern South China Sea
