张家界大坪镇灯影组古油藏特征及天然气勘探意义  

Characteristics of Dengying Formation Paleo-reservoir in Daping County,Zhangjiajie,and Its Natural Gas Exploration Significance

作　　者：刘安[1] 欧文佳[2] 危凯[1] 李芳[1] 李旭兵[1] LIU An OU Wenjia WEI Kai LI Fang LI Xubing(） Wuhan Institute of Geology and Mineral Resources, China Geological Survey, Wuhan , 430205 ） China University of Geosciences , Wuhan , 430074)

机构地区：[1]中国地质调查局武汉地质矿产研究所,武汉430205 [2]中国地质大学(武汉),武汉430074

出　　处：《地质学报》2017年第8期1848-1859,共12页Acta Geologica Sinica

基　　金：中国地质调查局基金项目"武陵-湘鄂西页岩气资源调查评价"(编号:12120114049801);国家重大专项下属课题任务"中扬子高演化页岩气赋存机理与富集规律研究"(编号:2016ZX05034001-002)联合资助成果

摘　　要：野外调查揭示大坪镇灯影组古油藏为裂缝型古油藏,受到滑脱构造控制,裂缝主要分布在灯影组上部;沥青大量充填在裂缝中心,少量沿缝合线分布,或浸染白云岩。通过分析,沥青的δ13 Corg、V/(V+Ni)平均值分别为—33.27‰、0.89,与牛蹄塘组烃源岩非常接近,因此大坪古油藏的油源可能是寒武系牛蹄塘组斜坡相区和盆地相区烃源岩。古油藏裂隙石英脉/方解石脉流体包裹体均一温度和拉曼光谱成分指示了中侏罗世以来古油藏裂缝形成、油气充注、以及因大气水下渗遭受破坏的过程。分析认为大坪古油藏北侧桑植—石门复向斜地区震旦系灯影组埋深近4km,油气保存条件相对较好,且滑脱带上下岩性差异会造成灯影组裂隙发育,对储层有明显的改善作用,具有形成次生气藏的可能性。Field survey reveals that the Daping Dengying Formation Paleo reservoir can be classified as fracture reservoirs. It is controlled by the detachment structure, with fractures mainly developed in the upper part of the Dengying Formation. A large volume of bitumen is filled in fractures, with minor distributed along the suture line or permeated through the surrounding dolomite. The analysis shows that the δ13Corg and V/（V＋Ni） values of the bitumen are -3327‰ and 089 respectively, which are close to that of the Niutitang Formation shales, indicating that the paleo oil reservoir likely sourced from the source rocks of slop belt and basin in the Cambrian Niutitang Formation. The homogenization temperatures and the Raman compositions of fluid inclusions in quartz or calcite vein fractures in the paleo reservoirs show that since middle Jurassic period, the paleo reservoirs have experienced fractures formation, hydrocarbon charging, destruction and underground fluid permeation. Our study shows that the Sinian Dengying Formation in the Sangzhi Shimen synclinorium in north of paleo oil reservoir has a burial depth of nearly 4 kilometer, which formed well preservation conditions for oil and gas. In addition, differences of lithology above or below the detachement belt caused fracture development of the Dengying Formation, which has distinct improvement for reservoirs and be of possibility to form the secondary petroleum reservoirs.

关 键 词：震旦系 裂缝 古油藏 油源 成藏 灯影组 张家界 

分 类 号：P618.13[天文地球—矿床学]