【作者】 张伟；

【导师】 张立强；

【作者基本信息】 中国石油大学(华东) ， 地质资源与地质工程， 2019， 硕士

【摘要】 本文以塔里木盆地顺托果勒地区志留系柯坪塔格组储层为研究对象,通过使用薄片观察、扫描电镜、阴极发光、全岩XRD分析等手段,结合流体包裹体均一温度、埋藏史等,对储层岩石学特征、成岩演化、油气充注史进行研究,并对各成藏期之前的储层物性进行恢复,在此基础上进行有利区的预测。本文根据各种颗粒以及钙质胶结物的含量对储层岩石相进行划分:将钙质胶结物含量低于15%的分为高塑性岩屑砂岩(塑性颗粒含量大于15%)、低塑性岩屑砂岩(塑性岩屑颗粒含量大于5%且小于15%)、贫塑性岩屑砂岩(塑性颗粒含量小于15%),钙质胶结物含量大于15%的定为钙质强胶结砂岩。研究区储层整体上处于中成岩A期,经历了较为复杂的成岩作用和三期油气充注。储层在沉积后经历了严重的压实作用,随后在距今417Ma发生了第一期油气充注和有机酸注入,之后地层抬升柯上段地层遭受大气淡水影响,早期油藏被破坏形成沥青,而后地层下降在310Ma时经历第二期油气注入并发生了大规模的胶结作用,随后在20Ma时储层经历了第三期油气注入。不同岩石相砂岩经历的成岩演化过程差异大,导致其在各油气充注时期物性存在差异:第一期油气充注时贫塑性岩屑砂岩和钙质强胶结砂岩物性较好,其次为低塑性岩屑砂岩,高塑性岩屑砂岩物性最差;第二期油气充注时钙质强胶结砂岩物性最好,其次为低塑性岩屑砂岩,贫塑性岩屑砂岩物性较差,高塑性岩屑砂岩物性最差,但是钙质强胶结砂岩在油气充注开始后迅速发育大规模的钙质胶结作用导致此类砂岩没有经历有效的油气充注;第三期油气充注时各类砂岩都较为致密,其中,低塑性岩屑砂岩物性最好,其次为贫塑性岩屑砂岩,钙质强胶结砂岩和高塑性岩屑砂岩物性较差。根据神经网络方法,使用自然电位、自然伽马、声波时差和密度等测井曲线,识别出柯下段存在低塑性岩屑砂岩和高塑性岩屑砂岩。柯上段存在贫塑性岩屑砂岩、低塑性岩屑砂岩和钙质强胶结砂岩。更多还原

【Abstract】 This thesis has studied the reservoirs of the Silurian Kepingtage Formation in the Shuntuoguole area of the Tarim Basin,through using integrated analyses of thin section,scanning electron microscopy,cathodoluminescence,full-rock XRD,and combined the fluid inclusions data and basin burial history.The study has carried out reservoir petrological characteristics,diagenetic evolution,and hydrocarbon charging history,and also restored the reservoir physical properties before each hydrocarbon accumulation period.Based on the aforementionde analyses,the favorable area of hydrocarbon accumulation has been predicted.In this thesis,four petrofacies of reservoir rocks has been defined according to the percentage of ductile lithic and calcareous cement,including sandstone with high ductile lithic content(ductile lithic>15% and calcareous cement<15%),sandstone with low ductile lithic content(15%>ductile lithic>5% and calcareous cement<15%),sandstone with limited ductile lithic content(ductile lithic<5% and calcareous cement<15%),and sandstone with calcareous cementation(calcareous cement > 15%).The Kepingtage Formation of study area has been interpreted as stage A of mesodiagenesis.This formation has experienced complex diagenesis and three episodes of hydrocarbon charging.The reservoir has experienced severe compaction soon after deposition and the first episode of hydrocarbon and organic acid charging occurred at 417 Ma.Then the Kepingtage Formation has been modified by atmospheric water and the oil has been altered to asphalt during the uplift.The reservoir has been experienced the second episode of hydrocarbon and organic acid charging at 310 Ma,and cenmented by silica and calcite largely.The third episode of hydrocarbon charging has occurred at 20 Ma.Each petrofacies has variable petrophysical characteristics at individual hydrocarbon charging episodes,which are resulted by different diagenetic processes.During the first episode of hydrocarbon charging,the sandstone with limited ductile lithic content and sandstone with calcareous cementation have good porosity,followed by sandstone with low ductile lithic content.The sandstone with high ductile lithic content has the lowest porosity.Before the second episode of hydrocarbon charging,the the porosity of the four petrofacies is ordered as sandstone with calcareous cementation,sandstone with low ductile lithic content,sandstone with limited ductile lithic content and sandstone with high ductile lithic content.However,the sandstone with calcareous cementation has decreased in porosity rapidly after the initiation of the second episode of hydrocarbon charging.Therefore,the sandstone with calcareous cementation is hydrocarbon poor.Each petrofacies has experienced densification before the third episode of hydrocarbon charging.During this time,the porosity of the four is ordered as sandstone with low ductile lithic content,sandstone with limited ductile lithic content,the sandstone with calcareous cementation and sandstone with high ductile lithic content.According to the BP neural network model,the well logs of spontaneous potential,gamma ray,acoustic and density have been used to identify the existence of sandstone with low ductile lithic content and sandstone with high ductile lithic content in the lower Kepingtage Formation and sandstone with limited ductile lithic content,sandstone with low ductile lithic content,calcareous cemented sand-stone in the upper Kepingtage Formation.更多还原