摘要
天然气水合物储层精确评价关系到储层的生产与开发过程.由于储层微观结构具有非均质性,且水合物合成分解过程中分布形式复杂,水合物储层物性变化规律尚不明晰,从而难以对储层水合物饱和度进行准确预测.为明确水合物赋存模式对电性特征的影响规律,本文基于石英砂样品采用随机模拟的方法实现了颗粒包裹型、孔隙填充型和团簇状分布三类赋存模式的水合物数字岩心构建,并进一步提取孔径分布分析不同水合物分布模式下的微观结构变化特征,利用有限元方法对含水合物数字岩心进行电性模拟,结合阿尔奇公式得到适用于含水合物石英砂介质的经验参数取值,并采用实验室内水合物合成实验电阻率测量数据与实际储层电阻率测井数据对比验证了阿尔奇经验参数取值的正确性及有效性.结果表明,随着水合物饱和度逐渐增加,在相同水合物饱和度下,颗粒包裹型生长引起的微观结构变化对电传导过程的影响最为显著;孔隙填充型水合物生长引起的孔隙结构变化对电传导过程影响最小;不同水合物赋存形式下,沉积物孔径分布变化规律从微观角度解释了三类分布模式的电性差异.研究结果有助于研究储层内含水合物沉积物合成分解过程中的电性特征演化规律.
The accurate evaluation of natural gas hydrate reservoirs is related to the production and development process of reservoirs.Due to the heterogeneity of the reservoir and the complex morphologies of hydrate during formation and dissociation,the physical properties evolution of hydrate reservoirs is not clear yet,and it is difficult to accurately predict the hydrate saturation of the reservoir.In order to clarify the influence of hydrate morphologies on electrical properties,the stochastic simulation method is used to construct hydrate digital rocks based on quartz sand samples with three types of hydrate morphologies:Grain-Coating,Pore-Filling and Patchy.The pore size distribution is extracted to analyze the microstructure evolution under different hydrate distribution patterns,and the finite element method is used to simulate the electrical properties of hydrate digital rocks.The Archie empirical parameters for hydrate-bearing quartz sands are obtained,and the Archie empirical parameter values are verified by using the resistivity data of hydrate formation experiments in laboratory and reservoir resistivity logging data.The results show that with the increase of hydrate saturation,the changes of microstructure caused by Grain-Coating hydrate growth have the most significant effect on electrical conduction process at the same hydrate saturation;The pore structure changes caused by Pore-Filling hydrate growth have the least influence on electrical conduction process;The different pore size distributions of sediment explain the electrical differences among the three types of hydrate morphologies.The results help to study the evolution of electrical properties during the formation and dissociation of hydrate-bearing sediments.
作者
田海涛
刘乐乐
夏宇轩
徐赛
韦伟
蔡建超
TIAN HaiTao;LIU LeLe;XIA YuXuan;XU Sai;WEI Wei;CAI JianChao(Institute of Geophysics and Geomatics,China University of Geosciences,Wuhan 430074,China;Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266237,China;School of Earth Resources,China University of Geosciences,Wuhan 430074,China;State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第4期1439-1450,共12页
Chinese Journal of Geophysics
基金
国家自然科学基金(41872136,42172159)资助.
关键词
天然气水合物
水合物赋存模式
电性特征
有限元模拟
数字岩心
微观结构
Natural gas hydrate
Gas hydrate morphology
Electrical properties
Finite element simulation
Digital rock
Microstructure
