川中地区龙王庙组高频层序与沉积微相及其对有利储层的控制

为明确川中地区龙王庙组沉积微相时空分布及其对储层的控制，利用地震、钻井及岩心资料，开展了精细的沉积、层序和储层研究，深入讨论了高频层序与沉积微相对有利储层的控制.龙王庙组主要发育鲕粒颗粒云岩、砂屑颗粒云岩、花斑状粉晶云岩等8种岩相，垂向上发育深水台地-滩间海型、颗粒滩型和局限潮坪型等3种岩相组合.龙王庙组构成1个三级层序，可分为2个四级层序（SQ1和SQ2），各四级层序可分为3~5个五级层序.高频层序格架内，颗粒滩和局限潮坪具明显的加积和朝东南方向进积趋势，SQ2颗粒滩和局限潮坪的发育优于SQ1.局限潮坪微相的窗格孔细晶-粉晶云岩和花斑状粉晶云岩孔隙度最好，主要分布于四级和五级层序的顶部；其次为高频层序中-上部的颗粒滩微相.与高频海平面变化相关的早期溶蚀是优质储层形成的关键，并为后期储层改造奠定了基础. 

High-Frequency Sequence and Microfacies and Their Impacts on Favorable Reservoir of Longwangmiao Formation in Central Sichuan Basin

Based on seismic data, well-logging and cores, an integrated research on the microfacies and sequence stratigraphy and reservoir characteristics is made, in order to clarify the controls of the high-frequency sequence and microfacies on the reservoirs in the Longwangmiao Formaion, Central Sichuan basin. The Longwangmiao Formation is mainly composed of eight types of lithofacies such as ooid grainstone, intraclast grainstone and spotted-structure silt crystalline dolomite. They can be grouped into three types of facies associations which are deep-platform to inter-shoal, grain shoal, and restricted tidal flat. The Longwangmiao Formation consists of one third-order sequence and two fourth-order sequences, and either fourth-order sequence includes three to five fifth-order sequences. In the high-frequency sequence stratigraphic framework, tidal flat and grain shoal deposits show clear aggregation and southeastern progradation trends, and they are better developed in SQ2 than in SQ1. The fine to silt crystalline dolomite and spotted-structure silt crystalline dolomite that developed in restrict tidal flat are best in porosity, and they are mainly distributed in the upmost part of the fourth- and fifth-order sequences. The shoal deposits are the second best in reservoir quality and they mainly developed in the middle and upper parts of the sequences below the tidal flat. The early-stage dissolution related to high-frequency sea-level fluctuations is the basis for the formation of the best reservoir of the Longwangmiao Formation in the Central Sichuan basin, and laid the foundation for the later improvement.