白云岩的残余结构及其沉积相的意义——以塔中地区中-下奥陶统为例

发布时间：2018-04-21 07:28

本文选题：白云岩 + 残余结构　；参考：《石油与天然气地质》2017年04期

【摘要】：白云岩虽然是一种沉积岩,原生、同生或准同生时期形成的泥晶-粉晶白云岩也常被视为局限-蒸发环境的指示标志,但埋藏条件下形成的交代白云岩或热液改造白云岩则不能直接作为沉积相标志,必须辨别白云岩的残余结构,并恢复原始灰岩的沉积环境。这对确定其沉积相及开展储层成因研究至关重要。以塔中地区中-下奥陶统白云岩发育段为例,这些白云岩就常被认为是局限-蒸发台地的标志。通过对取心段岩石类型的详细鉴定,以云质灰岩中的云化部分与未云化部分进行对比,建立了白云岩残余结构的识别标准。识别了白云岩的3种残余结构,发现白云岩以残余影像结构为主,残余粒屑结构和残余粒形结构很少,由此认为白云岩的原岩主要是一套颗粒滩相灰岩。中央隆起带早-中奥陶纪不属于前人所认为的局限-蒸发台地相,而是开阔台地相,且以发育台内滩亚相-高能砂屑滩微相为主。
[Abstract]:Although dolomite is a sedimentary rock, primary, syngenic or quasi-syntectic mudstone is often regarded as an indicator of limit-evaporation environment. However, metasomatic dolomite formed under burial conditions or hydrothermal altered dolomite cannot be used as a direct indicator of sedimentary facies. It is necessary to distinguish the residual structure of dolomite and restore the sedimentary environment of the original limestone. It is very important to determine the sedimentary facies and study the reservoir genesis. Taking the middle and lower Ordovician dolomite formation in the central Tarim area as an example, these dolostones are often regarded as a sign of limit-evaporation platform. Based on the detailed identification of the rock types in the core section, the identification criteria for the residual structure of dolomite are established by comparing the clouded part with the unclouded part of the dolomite. Three kinds of residual structures of dolomite are identified. It is found that the residual image structure is the main structure of dolomite, and the residual grain debris structure and residual granular structure are few. It is concluded that the original dolomite is mainly a set of granular beach limestone. The central uplift zone did not belong to the limit-evaporative platform facies in early and middle Ordovician, but was open platform facies, and was dominated by the subfacies of the developed platform and the microfacies of the high-energy sand debris beach.
【作者单位】：北京大学地球与空间科学学院石油与天然气研究中心;中国石油海外勘探开发公司;中国石化西北油田分公司;陕西延长石油国际勘探开发工程有限公司;
【基金】：国家自然科学基金项目(41672123,41002029,41272137,41572117)
【分类号】：P588.245;P618.13

【相似文献】