四川盆地东部石炭系黄龙组岩溶角砾碳酸盐岩特征  

Characteristics of karst brecciated carbonate of Carboniferous Huanglong Formation in the eastern Sichuan Basin

作　　者：朱智鹏[1] 黄勇[1] 汪洋[2] 

机构地区：[1]西南石油大学资源与环境学院 [2]中国石油西南油气田公司重庆气矿

出　　处：《天然气工业》2013年第5期40-45,共6页Natural Gas Industry

基　　金：中国石油西南油气田公司科研项目(编号:XNS14NH2011-001)

摘　　要：四川盆地东部中石炭统黄龙组普遍发育的角砾碳酸盐岩主要为准同生与岩溶两种类型,为有效区分这两种角砾碳酸盐岩,加深对储层成岩演化的认识,重点研究了岩溶角砾碳酸盐岩的特征。根据该区89口井的岩心观察描述与测井分析结果及部分井的碳—氧稳定同位素分析结果,认为黄龙组岩溶角砾碳酸盐岩具有如下特点:①主要为岩溶角砾白云岩,发育崩坍型、运积型与缝溶型3种类型,并以运积型为主,且局限分布于黄龙组中上部;②角砾与基质的碳氧同位素特征差异较大,基质不纯,角砾间充填较多的泥质或含泥质、铁质的碳酸盐岩胶结物;③具有高自然伽马值与低电阻率特征。综合分析后的结论认为:崩坍型岩溶角砾白云岩厚度较大,但仅局限分布,且储集性能极差;运积型岩溶角砾白云岩虽层薄,但部分在流水溶蚀作用下可以发育成较好的储集体;缝溶型岩溶角砾白云岩溶蚀孔缝发育,是有利的储集体,但分布较少。Brecciated carbonates were widely developed in the upper Carboniferous Huanglong Formation of the eastern Sichuan Basin, and they include two main types： penecontemporaneous brecciated carbonates and karst brecciated carbonates. In order to effectively distinguish the said two types of brecciated carbonates and recognize diagenesis evolution of reservoirs, this study focuses on the characteristics of the latter type. Therefore, all types of data were first collected in this study area： the observation and descrip tion of core samples from 89 wells, well logging interpretation, and carbon and oxygen stable isotopes. On this basis, an in-deep in- vestigation was then made into the characteristics of karst brecciated carbonates in the Huanglong Formation. a. The karst brecciated carbonates can be further divided into slacktip packing type, transport packing type and crack-corrosion type, and the second type is the dominant one confined to the upper and middle parts of the Huanglong Formation. b. There is a big difference in the features of carbon and oxygen isotopes between matrix and breccia： compared to the impure matrix, there filled in breccia with muddy, argillaceous, or argilloferruginuous carbonate cement, c. The karst brecciated carbonates presents a high gamma ray value and low resistiv ity. Finally, through a comparative study of the said three types of karst breceiated carbonates in this study area, the following findings were concluded： The slacktip packing type brecciated dolomites are rather thick but is only distributed in a limited area, thus are not favorable reservoirs; the transport packing type brecciated dolomites are much thinner, but some of them can be possibly devel- oped as favorable reservoirs through water dissolution; the crack-corrosion type brecciated dolomites are most favorable reservoirs with developed corroded pores and fissures but distributed in a small area.

关 键 词：四川盆地 石炭纪 黄龙期 角砾碳酸盐岩 岩溶角砾 碳氧同位素 电性特征 白云岩 

分 类 号：P618.13[天文地球—矿床学]