摘要
在介绍鄂尔多斯盆地吴堡地区延长组长6段沉积特征的基础上,探讨了该储层物性特征、浊积岩特征、浊积岩分布规律及其对油藏的影响,明确了浊流沉积的石油地质意义。结果表明:鄂尔多斯盆地吴堡地区长6段以发育长石砂岩为主,填隙物成分有方解石、绿泥石、白云母以及少量的石英加大、长石加大等,砂岩储集层孔隙结构具有很强的非均质性;吴堡地区长6期湖盆沉降趋于稳定,是三角洲的高建设时期;多水系、多物源的三角洲前缘沉积为深湖浊积扇沉积提供了充足的物质基础;在吴堡地区东北部三角洲前缘水下分流河道前端发育深湖浊积扇沉积,可区分出中心微相和边缘微相两个沉积微相带,其中浊积扇中心微相以细砂岩、粉砂岩与暗色泥岩呈砂泥互层;从平面上看,浊积岩砂体非均质性在侧向上逐渐变弱,砂体底部发育厚度较大、成熟度较高的暗色湖相沉积的烃源岩,深湖相的暗色泥岩含有丰富的烃源岩,而浊积岩砂体是由深湖相的暗色泥岩构成,孔渗物性好的区域易于形成良好的上倾尖灭的透镜状岩性油藏。
Based on the introduction of sedimentary characteristics of Chang-6 Section in Yanchang Formation of Wubu Area, Ordos Basin, the physical property, turbidite characteristics and turbidite distribution of Chang-6 Section and their influence on oil reservoir were analyzed, and the petroleum geological significance of turbidite was discussed. The results showed that the main rock type of Chang-6 Section in Wubu Area of Ordos Basin was feldspathic sandstone, and the composition of interstitial material included calcite, chlorite, white mica and a little quartz overgrowth and feldspar overgrowth, etc. ; the anisotropism of pore structure of sandstone reservoir was very strong; the lacustrine basin settlement tended to stable in Chang-6 Section of Wubu Area, and was the high construction period of delta; the delta front sediment, which included multiple water systems and provenances, provided sufficient materials for the deep lacustrine turbidite fan sediment; the front of underwater distributary channel of delta front developed deep lacustrine turbidite fan sediment in the northeast of Wubu Area, and center microfacies and edge microfacies were distinguished in the sediment; packsand and siltite were interbedded with dark mudstone in center microfacies of turbidity fan; in horizontal, the anisotropism of turbidite sandbodies gradually weakened in the lateral direction, and the sandbodies at the bottom developed hydrocarbon source rocks which were dark lacustrine facies sedimentary with higher thickness and maturity; dark mudstone of deep lacustrine facies was rich in hydrocarbon source rock, and turbidite sandbodies were composed of the dark mudstone, so that it was easier to successfully form the updip pinchout and lentieular lithological reservoir in the region with good permeability and porosity property.
出处
《地球科学与环境学报》
CAS
2012年第2期64-71,共8页
Journal of Earth Sciences and Environment
基金
国家自然科学基金项目(40872087)
关键词
浊流沉积
沉积微相
物性特征
岩性圈闭
长6段
延长组
吴堡地区
鄂尔多斯盆地
turbidity deposition
sedimentary microfacies
physical property
lithologic trap
Chang-6 Section
Yanchang Formation
Wubu Area
Ordos Basin
