摘要
孔隙充填和裂隙充填是自然界中水合物赋存的两种基本形态,其类型判别对储量评价、钻井安全以及环境评估均具有重要影响。本文模拟南海孔隙充填和裂隙充填两种类型水合物储层,利用岩石物理模型和声学模拟实验获取声波速度和密度,对两种类型的识别方法进行了探索。结果显示,孔隙充填和裂隙充填型水合物沉积体系的纵波速度都随水合物体积分数的增大而增大,密度都随水合物体积分数增大而减小。将速度与密度参数结合计算两种类型水合物阻抗和ρ√Vp属性表明:对于含孔隙充填型水合物沉积体系的ρ√Vp属性,岩石物理模拟的计算结果与实验结果斜率均为正;而对于含裂隙充填型水合物沉积物的ρ√Vp属性,其斜率均为负。但当水合物体积分数小于40%时,含裂隙充填型水合物沉积物的理论计算结果与实验值存在偏差,因此,在计算低体积分数水合物的ρ√Vp属性时,需要对模型进行适当修正。本文利用ρ√Vp属性对GMGS2航次16井赋存的孔隙充填和裂隙充填型水合物进行了验证,结果表明井中上部分赋存的水合物以裂隙充填型为主,底部以孔隙充填型为主,验证结果与实际钻探结果一致,表明该方法用于识别水合物类型是可行的。
Pore-filling and fracture-filling are two of the basic occurrences of natural gas hydrates in nature.To discriminate the type of gas hydrate is critically important for resource assessment,drilling safety and environment evaluation.In this paper,simulation experiment was carried out for the pore-filling and fracture-filling hydrate reservoirs in the South China Sea.The acoustic velocity and density of the two kinds of hydrate are obtained by petrophysical simulation and acoustic experiment simulation.The results suggest that the P wave velocity of the depositional mediums containing pore-filling and fracture-filling hydrate tends to increase with the volume fraction of hydrate,while the density decreases.Furthermore,we tested the impedance and theρ√Vp property of the two types of hydrate by combining velocity and density parameters together.The results also show that for the pore-filling hydrates,the properties ofρ√Vp calculated by the petrophysical models and experimentalρ√Vp both show positive slope,while Theρ√Vp property of the fracture-filling hydrate shows negative slope.However,the differences between the model and experiment results of fracture-filling hydrate are obvious when the volume fraction of gas hydrate is less than 40%.It means that the petrophysical for fracture-filling hydrate needs to be further improved.In addition,pore-filling and fracture-filling hydrate in GMGS2-16 Site has been verified by the property ofρ√Vp The results show that the hydrate in the upper part of the well is mainly fracture-filling hydrate,as the bottom dominated by pore-filling hydrate.The verification has been confirmed by actual drilling results.
作者
景鹏飞
胡高伟
卜庆涛
陈杰
万义钊
毛佩筱
JING Pengfei;HU Gaowei;BU Qingtao;CHEN Jie;WAN Yizhao;MAO Peixiao(Laboratory of Gas Hydrate,Ministry of Natural Resources,Qingdao Institute of Marine Geology,Qingdao 266071,China;Chinese Academy of Geological Sciences,Beijing 100037,China;Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266071,China)
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2020年第6期208-218,共11页
Marine Geology & Quaternary Geology
基金
国家实验室开放基金“南海北部水合物多分支孔降压开采方法研究”(QNLM2016ORP0207)
国家重点研发计划项目“水合物试采目标综合评价技术应用示范”(2017YFC0307602)
国家自然科学基金“南海富含有孔虫沉积物中水合物形成及其声学响应机理研究”(41474119)
“裂隙充填型水合物声学响应机理研究”(41906067)
中国博士后科学基金“甲烷通量对南海沉积物中水合物形成及声学特性影响研究”(2018M632634)
山东省自然科学基金“基于声学-CT联合探测的水合物分解及其声学响应机理研究”(ZR2019BD051)
山东省博士后创新项目“裂隙充填型天然气水合物声学响应研究”(201902050)。
