四川盆地下寒武统豹斑灰岩成因机理及其对储层的影响

发布时间：2018-03-08 21:31

本文选题：选择性白云化　切入点：豹斑灰岩　出处：《石油与天然气地质》2017年04期 　论文类型：期刊论文

【摘要】：豹斑灰岩(云岩)的广泛发育引起了地质学者的关注,目前其成因机理存在很大争议,因此研究豹斑灰岩(云岩)的特征、成因,以及与储层的关系,对于油气勘探具有重要意义。通过对4条基干剖面豹斑发育层段的宏观沉积相分析和镜下描述,结合X-射线衍射分析、扫描电镜、电子探针和同位素等分析手段,详细解剖了四川盆地下寒武统龙王庙组和天河板组豹斑灰岩的岩相及地球化学特征,并探讨了其成因机理。四川盆地下寒武统豹斑发育的基质灰岩主要有(含颗粒)泥微晶灰岩和砂屑亮晶灰岩,不同基质灰岩内的豹斑在斑块形态、泥质含量、白云石大小晶形方面具有较大差异,故可将豹斑分为3类:泥质云斑、含泥云斑和云斑。泥质云斑和含泥云斑主要发育于(含颗粒)泥微晶灰岩中,云斑内部由他形至半自形的泥粉晶白云石晶体组成;云斑主要发育于砂屑亮晶灰岩中,内部由自形-半自形粉细晶(部分中粗晶)白云石组成。(含颗粒)泥微晶灰岩的豹斑灰岩形成于海侵期潮下浅水低能环境,是交替沉积的灰泥质和云泥质软泥受后期风浪扰动或负载压实,再经历埋藏改造,形成纵向上具有韵律特征的云斑。亮晶砂屑灰岩的豹斑主要形成于浅埋藏期,与富镁高盐地层水沿孔渗较好的部位渗透至固结成岩地层中发生渗透回流白云化有关。豹斑内部粉细晶白云石的晶间孔十分发育,该类灰岩能否形成优质储层受控于豹斑在全岩中的含量。
[Abstract]:The widespread development of leopard porphyry (dolomite) has attracted the attention of geologists, and its genetic mechanism is controversial. Therefore, the characteristics, genesis and relationship with reservoir of leopard porphyry (dolomite) are studied. It is of great significance for oil and gas exploration. By means of macroscopic sedimentary facies analysis and microscopical description of 4 base-dry sections of Leopard development zone, combined with X-ray diffraction analysis, scanning electron microscope, electron probe and isotopic analysis, etc. The lithofacies and geochemical characteristics of the leopard porphyry of the lower Cambrian Longwangmiao formation and Tianheban formation in Sichuan Basin are dissected in detail. The genetic mechanism is also discussed. The matrix limestone developed in the Lower Cambrian Leopard in Sichuan Basin mainly consists of marl micrograined limestone and sandclastic lime-rock, and the leopard spots in different matrix limestone are in patch shape and mud content. There are great differences in crystal shape of dolomite, so leopard spots can be divided into three categories: muddy cloud spots, muddy cloud spots and cloud spots. Muddy cloud spots and mud cloud spots mainly develop in (granular) mud microcrystalline limestone. The interior of the cloud spot is composed of mudpowder dolomite crystals of anatomorphic to semi-automorphism, and the cloud spot is mainly developed in the sand-clastic bright grained limestone. The leopard porphyry composed of fine-grained (partially coarse) dolomite (partially coarse) in the inner part of the magnetomorphic powder. (containing particles) the leopard porphyry limestone formed in the shallow water low energy environment under the transgression period. The alternately deposited plaster and cloud mud were disturbed by the wind and waves or compacted by the load, and then underwent burial transformation to form longitudinal rhythmic cloud spots. The leopard spots of the bright grained sand limestone were mainly formed during the shallow burial period. It is related to the permeation and reflux dolomitization of the water along the pore and permeability in the high salt formation rich in magnesium and high salt. The intergranular pores of the fine dolomite in the interior of the leopard spot are well developed. Whether this kind of limestone can form high quality reservoir is controlled by the content of Leopard in the whole rock.
【作者单位】：中国地质大学(北京)能源学院;中国石化石油勘探开发研究院;中国石油大学(北京)地球科学学院;
【基金】：中石化科技部项目(G5800-15-ZS-KJB006) 国家自然科学基金重点资助项目(U1663209)
【分类号】：P588.2;P618.13

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