柴达木盆地尕斯地区古近系砂岩储层流体-成藏演化特征  

Reservoir fluid evolution and hydrocarbon charge history of the Gasi E_3~1 Oilfield,southwestern Qaidam Basin

作　　者：桂丽黎[1,2] 赵孟军[1,2] 刘可禹[1,2,3] 罗秘 孟庆洋[1,2] 袁莉 郝加庆[1,2] 

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油天然气集团公司盆地构造与油气成藏重点实验室,北京100083 [3]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [4]新疆油田公司风城油田作业区工艺所,新疆克拉玛依834000 [5]中国石油青海油田勘探开发研究院,甘肃敦煌736202

出　　处：《天然气地球科学》2016年第2期289-297,319,共10页Natural Gas Geoscience

基　　金：国家科技重大专项“中西部前陆盆地大型油气田形成、分布与区带评价”项目(编号:2011ZX05003-001);中国石油股份公司重大专项“前陆盆地油气成藏规律、关键技术及目标评价”项目(编号:2011B-04);中国石油股份公司重大专项“要素与过程约束的油气系统分析、模拟与评价“项目(编号:2011A-0207)联合资助

摘　　要：柴达木盆地西南部尕斯地区古近系下部（下干柴沟组下段,E_3~1）砂岩油藏是柴达木盆地主力油藏之一。以跃检1井为例,通过多功能显微镜、阴极发光、扫描电镜、X-射线衍射、包裹体测温等手段的应用,对储层的岩性、自生矿物、成岩共生序列、烃类包裹体分布及期次等进行了系统分析,研究了储层的流体—成藏演化特征。结果表明,储层砂岩主要为长石岩屑砂岩和岩屑长石砂岩,成岩共生序列为早期方解石/黏土包壳→长石溶蚀/石英加大→长石加大/晚期方解石→长石加大溶蚀/微晶石英→白云石→晚期绿泥石→硬石膏;储层流体经历了碱性—酸性—碱性—弱酸性—碱性的演化过程。其中酸性流体包括了黄色荧光和蓝色荧光气液烃包裹体所代表的2期油气充注,捕获时间分别为28Ma和8Ma;结合构造演化史与油气地球化学特征,提出了尕斯E_3~1油藏经历了上干柴沟组（N1）低熟原油和上油砂山组（N22）至现今的2期油气调整改造的成藏过程。The Gasi Oilfield is a major petroleum province in the Qaidam Basin.The hydrocarbon charge history of the Gasi E_3~1 Oilfield was studied through a detailed reservoir diagenesis and fluid inclusion investigation using optical microscopy,Cathodoluminescence（CL）microscopy,scanning electron microscopy（SEM）,XRD,fluid inclusion petrography and microthermometry.The reservoir diagenetic diagenesis comprises the followingsequence：anearlycalcite/Claycladding→Feldspardissolution/quartzovergrowth→late calcite/Feldspar overgrowth→Feldspar overgrowth dissolution/microcrystalline quartz→dolomitethe→anhydrite chlorite→anhydrite;while the reservoir fluids evolved from alkalic→acidic→alkalic→acidic→alkalic conditions.The abundance of quartz overgrowth,calcite and illite is negatively correlated with the reservoir quality,whereas chlorite is positively correlated with the reservoir quality.Two episodes of oil charge occurred in the reservoir.The first episode is represented by predominantly yellow fluorescing oil inclusions being contemporaneous with or just prior to the quartz overgrowth.The second episode is represented by blue fluorescing fluid inclusions occurred after the precipitation of dolomite.The two oil charges occurred around 28 Ma and 8Ma,respectively.The hydrocarbon reservoir model is characterized by an early major accumulation and a late minor charge with multiple concomitant readjustment.

关 键 词：砂岩储层特征 流体演化过程 油气包裹体 成藏过程 古近系 尕斯油田 

分 类 号：TE122.3[石油与天然气工程—油气勘探]