辽河东部凹陷新生界火成岩岩性、岩相特征和储层控制因素

Lithology,Lithofacies Chracteristics and Reservoir Control Factors of Cenozoic Igneous Rocks in Eastern Sag of Liaohe Depression

基于110口探井1 100m岩心、500余口探井总长107 000m火成岩井段资料,通过岩心观察、岩矿鉴定、物性测试和含油气性分析,研究了辽河坳陷东部凹陷新生界不同层系火成岩岩性、岩相发育特征和储层控制因素。结果显示:本区发育火山岩、侵入岩、沉火山碎屑岩3大类16种岩性,其中玄武岩类占91.0%;发育6相16种亚相,其中溢流相占63.0%;发育4类9种储集空间,次生孔隙和次生裂缝占主体。砾-粒间孔隙和裂缝发育的粗面岩类、玄武质火山碎屑(熔)岩和火山口—近火山口相带的侵出相、火山通道相和爆发相是最有利的储集岩性、岩相带。储层主要受岩性、岩相、断裂等多方面控制,岩性决定储集空间类型和储层微观特征,岩相控制储层宏观分布规律,断裂控制岩体分布范围、火山口位置和储层有效性。近油源、靠断裂的优势岩性、岩相带是火成岩油气勘探最有利目标。

On the basis of 110 wells with 1 100 meters drilling cores and 500 wells with 107 000 meters long sections of igneous rocks in the Eastern sag of Liaohe depression,lithology and lithofacies of the Cenozoic intermediate and mafic igneous rocks and reservoir control factors were studied by means of description,core slice identification,and reservoir physical property data analysis.Based on these data,16 types of volcanic,intrusive rocks and volcanic sedimentary rocks were recognized.Basaltic lava and basaltic volcanoclastic rocks are thick and widely distributed(91.0%).The volcanic rocks are mainly divided into 6 lithofacies and 16 sub-facies,of which the effusive lithofacies accounts for about 63.0%.The reservoir space can be grouped into 4 types and 9 sub-types,and the secondary porosity and fractures are widely developed in the study area.Trachytic lava and trachytic volcanoclastic rocks,basaltic volcanoclastic rocks,extrusive dome facies,volcanic conduit facies,and explosive facies are the most favorable reservoirs.Three factors including lithology,lithofacies and faults are considered to be related to the porosity and permeability of igneous rocks reservoirs.Lithology determines the type and microscopic characteristics of reservoirs;lithofacies controls the development of primary pores and distribution of reservoirs;faults control the range of igneous rocks,position of vent lithofacies and proximal lithofacies,and effectiveness of reservoirs.The favorable areas for petroleum accumulation are near oil sources,superior lithology and lithofacies belts with high structures adjacent to faults.