塔里木盆地寒武—奥陶系深层白云岩储层物性高压模拟实验及其孔隙特征研究  

High Pressure Simulation Experiment and Porosity Characteristics of Cambrian-Ordovician Deep Buried Dolostones in Tarim Basin

作　　者：谭俊英[1] 朱井泉[1] 刘玲[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029

出　　处：《现代地质》2015年第3期653-664,共12页Geoscience

基　　金：国家科技重大专项"深层有效储集体形成;分布规律与预测技术"(2008ZX05008)

摘　　要：塔里木盆地寒武—奥陶系白云岩埋藏深、地质年代老,是重要的油气储层。根据初步的物性测试从中挑选出具有较好孔渗性的白云岩类型:叠层石白云岩、重结晶白云岩和斑状白云岩。为了充分考虑埋藏深度、岩石成分及结构构造对其储层物性的影响,特设计原位模拟实验,研究白云岩的孔渗性在埋藏条件下的变化规律,并分析其原因和影响因素,同时通过光学显微镜和扫描电镜观察等手段研究其岩石学特征和储集空间类型。在参与实验的所有样品中,叠层石白云岩显示出良好的孔渗性,由窗格孔和晶间孔组成的孔隙体系具有优良的连通性和抗压性,在深埋藏条件下能较好地保持其孔渗性。重结晶白云岩也具有较好的储层物性,这得益于其较大的晶间孔,而晶间孔的大小取决于白云石晶体的含量、大小以及自形程度。斑状白云岩在深埋藏条件下的储层物性较差,其缝合线孔隙在高围压下很难保存。Cambrian-Ordovician dolostone in Tarim Basin is an important oil and gas reservoir with the characteristics of deep buried depth and old geological age. According to the preliminary tests of properties,several dolostones with good porosity and permeability： stromatolite dolostone,crystalline dolostone and patchy dolostone,are chosen. In order to fully consider the impact of buried depth,rock composition and structure on reservoir physical property,an in situ simulation experiment to research the permeability changing law of these dolostones under the buried condition is designed,and the causes and influence factors are analyzed. At the same time,its petrology characteristics and pore types are studied by means of optical microscope and scanning electron microscope. Of all the samples for this experiment,stromatolite dolostone shows the best permeability,whose pore system has good connectivity and compressive resistance,and is composed of fenestral pores and intercrystal pores,so its good permeability can be maintained under the deep buried condition. Crystalline dolostone with good permeability owes to its larger intercrystal pores,which depends on the content,size and crystal shape of the dolomite. Patchy dolostone reviews poor permeability under the deep buried condition,as its stylolite pores under high confining pressure is difficult to preserve.

关 键 词：白云岩 深埋藏 模拟实验 渗透率 孔隙 

分 类 号：TE122.2[石油与天然气工程—油气勘探]