湘鄂西壶瓶山—走马地区灯影组储层特征

中扬子地区震旦系广泛发育碳酸盐岩，是靠下部的海相组合中最有希望取得突破的油气勘探目的层系之一。通过走廊大剖面油气地质调查及野外露头地层剖面的测制，结合前人成果，对壶瓶山-走马地区灯影组地层及沉积相重新进行了研究，根据地表露头系统的岩石及铸体薄片和储层物性样品等的鉴定测试分析认为，该区灯影组主体为碳酸盐岩，自下而上可划分为3个岩性段。灯影组底部与下伏陡山沱组整合接触，顶部与上覆牛蹄塘组呈平行不整合接触，累计地层厚度242～339m，属局限台地潮坪－开阔台地－台缘斜坡沉积环境。其中，储层厚度为210.4m，占地层总厚度的72.7%；储集岩类主要为颗粒白云岩、泥晶白云岩、砂屑白云岩及鲕粒灰岩等。储集空间有晶间孔、粒间溶孔及裂缝等；孔隙度一般值为0.69%～2.66%，最大值为3.52%，平均值为1.52%；渗透率最大值为6.2812×10-3μm2，平均值为0.3000×10-3μm2，属低孔低渗-特低孔低渗储层；主要孔喉类型为小喉道和微喉道。总体而言，灯影组储集性能较差，储层属Ⅲ类储层，但该组构造裂缝较发育，可改善储集性能，故该组储层有可能成为较好的储集层。若其上具良好的盖层和圈闭，可望发现一定规模的工业性天然气藏。

Reservoir characteristics of Dengying Formation in Hupingshan-Zouma area of western Hubei-Hunan region

Sinian carbonate rocks are widely developed in the study area, and these rocks constitute one of the most hopeful oil-gas exploration target strata where a breakthrough is likely to be made in the lower marine combination. Through oil-gas geological survey along the profile and the stratigraphic section measurement of the outcrops, in combination with the previous achievements, the authors restudied the strata and sedimentary facies of Dengying Formation in Hupingshan-Zouma area. According to systematic identification and analysis of the rock slices, casting body slices and reservoir property samples of the outcrops, the authors hold that the Dengying Formation is mainly composed of carbonate rocks, which can be divided into three lithologic sections in upward succession. The strata are in conformable contact with the underlying Doushantuo Formation, and in parallel unconformable contact with the overlying Niutitang Formation, with the total thickness being 242～339m, belonging to the sedimentary environment of tidal flat of the restricted platform-open platform-slope of the platform edge. In the strata, the reservoir thickness is 210.4m, which possesses 72.7% of the total stratigraphic thickness; the reservoir rocks are composed mainly of granular dolomite, micrite dolomite, psammitic dolomite and oolitic limestone; the reservoir space comprises mainly intercrystalline pores, intergranular dissolved pores and fissures; the porosities are mainly 0.69%～2.66%, with the maximum value being 3.52% and the average value being 1.52%; the maximum value of the permeability is 6.2812×10-3μm2. and the average value is 0.3000×10-3μm2. the main pore types are small throats and micro throats. On the whole, the reservoir property of the Dengying Formation is rather poor, and it is comprehensively evaluated as a Ⅲ-grade reservoir; nevertheless, structural fractures of the Dengying Formation are well developed, which can improve the reservoir property, and it is also hopeful for the reservoir to become a good reservoir. If there exist good caps and traps above the Dengying Formation, it is possible to find commercial gas reservoirs of certain sizes in the Dengying Formation.