鄂尔多斯盆地庆阳气田深层致密砂岩气藏成藏条件  

Reservoir-forming conditions of deep tight sandstone gas reservoirs,Qingyang gasfield,Ordos Basin

作　　者：蒙晓灵[1,2] 艾庆琳[1,2] 王金成[1,2] 卞晓燕[1,2] 朱长荣[1,2] 安文宏[1,2] 谢姗 夏守春[1,2] 蒋培明[3] Meng Xiaoling;Ai Qinglin;Wang Jincheng;Bian Xiaoyan;Zhu Changrong;An Wenhong;Xie Shan;Xia Shouchun;Jiang Peiming(Exploration and Development Research Institute,PetroChina Changqing Oilfield Company,Xi’an,Shaanxi 710018,China;National Engineering Laboratory of Low-Permeability Oil&Gas Exploration and Development,Xi’an,Shaanxi 710018,China;Production Well-logging Center,CNPC Logging Company Limited,Xi’an,Shaanxi 710077,China)

机构地区：[1]中国石油长庆油田公司勘探开发研究院 [2]低渗透油气田勘探开发国家工程实验室 [3]中国石油集团测井有限公司生产测井中心

出　　处：《天然气勘探与开发》2021年第1期104-110,共7页Natural Gas Exploration and Development

摘　　要：近年来,鄂尔多斯盆地西南部深层(4200 m以下)天然气勘探取得了重要进展。为进一步揭示研究区致密砂岩成藏条件,利用石油地质学理论和油气成藏原理,基于岩心观察、普通薄片、扫描电镜等资料分析,结合地球化学特征,对其烃源岩分布、生烃能力、储集层特征进行系统剖析,并对成藏模式进行了探讨。研究认为:①该区主力烃源岩上古生界石炭系上统本溪组缺失,减薄的二叠系下统太原组、山西组山2段煤系地层仍不失为良好的烃源岩,干酪根类型以偏腐殖型、腐殖型为主,为高成熟—过成熟热演化阶段;②山西组山1段储层砂体发育,是纵向上的优势储集层段,受西南物源控制,山西组有效储集岩岩性以中粗粒石英砂岩、岩屑石英砂岩为主,其物性总体呈现“特低孔隙、特低渗透”特征;③由于埋深大,压实作用对岩石孔隙影响显著,但由于石英等刚性组分的存在,在强烈压实作用下仍能保存少许原生孔隙,并在后期构造运动中更易产生微裂缝,这为油气的运移和聚集提供了重要通道;④二叠系中统石盒子组盒8层砂体不发育,其间发育的细—粉砂岩和泥岩共同构成区域盖层。结论认为,在致密砂岩储层背景下,较好的烃源岩、单一的优势储集层、优质的区域盖层构成了研究区天然气富集成藏的重要条件。Recently,a great exploration progress has been made in some deep gas(burial depth more than 4200 m),southwestern Ordos Basin.So,in order to further reveal reservoir-forming conditions of tight sandstone gas reservoirs in this study area,based on data from core observation,thin-section identification,and scanning electron microscopy(SEM),combined with geochemical characteristics,the source-rock distribution,hydrocarbon-generating capacity,and reservoir characteristics were systematically analyzed according to certain petroleum geological theory and reservoir-forming principle.In addition,reservoir-forming modes were discussed.Results show that(1)in this area,even through the main source rock of Upper Paleozoic Upper Carboniferous Benxi Formation is absent,the coal strata of both thinned Lower Permian Taiyuan Formation and Shanxi 2 Member are quite good source rocks.Their kerogen is mainly dominated by type II2 and type III,and they are in the thermal evolution stage of high maturity and over maturity;(2)developed with sandbody,the Shanxi 1 Member belong to the dominant reservoir section in the vertical direction.Affected by southwestern provenance,the effective reservoir rocks in the Shanxi Formation are lithologically dominated by medium-to coarse-sized quartz sandstone and lithic quartz sandstone.And their physical properties are overall characterized by extra low porosity and permeability;(3)due to deeper burial depth,compaction has an obvious impact on rock pores,but for the sake of the coexistence of quartz and other rigid compositions,a few primary pores are still remained even under strong compaction,and microfractures can be induced easily during the later tectonic activities,which may provide some important pathway for hydrocarbon migration and accumulation;and(4)with undeveloped sandbody,the Shihezi 8 Member which is composed of fine sandstone,siltstone,and mudstone constitutes regional caprocks.In conclusion,better source rocks,single dominant reservoirs,and regional caprocks with high quality are the i

关 键 词：鄂尔多斯盆地 庆阳气田 上古生界 深埋藏 致密砂岩气藏 成藏条件 烃源岩 岩性圈闭 

分 类 号：P618.13[天文地球—矿床学]