银额盆地下白垩统巴音戈壁组泥岩地球化学特征及其古环境意义  

Geochemical characteristics and their paleoenvironmental significance of the mudstones from the Lower Cretaceous Bayingebi Formation in the Yin’e Basin

作　　者：李继东[1] 付玉鑫 蒋飞虎[1] 李妲 王亚明[1] 刘云龙 郑伟[2] 邢智峰[2] LI Jidong;FU Yuxin;JIANG Feihu;LI Da;WANG Yaming;LIU Yunlong;ZHENG Wei;XING Zhifeng(Research Institute of Exploration and Development,Zhongyuan Oilfield Company,Sinopec,Puyang 457001,Henan,China;College of Resources and Environment,Henan Polytechnic University,Jiaozuo 454000,Henan,China)

机构地区：[1]中国石化中原油田分公司勘探开发研究院,河南濮阳457001 [2]河南理工大学资源环境学院,河南焦作454000

出　　处：《河南理工大学学报（自然科学版）》2022年第3期48-56,65,共10页Journal of Henan Polytechnic University（Natural Science）

基　　金：中石化集团公司科技攻关项目(P19022-1);国家自然科学基金资助项目(41772110,41102008);河南省高等学校重点科研项目(20A170010)。

摘　　要：银额盆地拐子湖凹陷巴音戈壁组为中原油田银额新区主力含油层系,该区沉积记录及古环境特征的研究,对拐子湖凹陷的沉积演化及巴音戈壁组储层评价具有重要意义。以拐参1井下白垩统巴音戈壁组取心资料为基础,对不同层位泥岩的微量元素及稀土元素等测试结果进行分析,探讨巴音戈壁组古环境演化规律。对V,Ni,Sr,Ba,Cu等环境敏感元素及Ce_(anom)地球化学特征进行综合分析,结果表明:拐参1井巴音戈壁组形成于咸水→淡水→半咸水贫氧环境,且沉积期古气候总体表现为干旱炎热→温暖湿润→半干旱特征。其中,古盐度指标w(Sr)/w(Ba)和w(Sr)/w(Cu)呈较强的正相关关系,表现为古盐度增加和古气候的干燥期基本一致。结合孢粉化石分析结果,推测该组含油页岩岩系沉积期气候较温暖湿润,有利于有机质产出与保存;半咸水-咸水环境有利于有机质富集,从而形成高品质含油页岩。The Bayingebi Formation in the Guaizihu Depression is one of the main oil-bearing strata in the Yin’e Basin.Investigating on its sedimentological and paleoclimatic features is of great significance to understand the evolution process of the Guaizihu Depression and to improve the reservoir evaluation of the Bayingebi Formation.For this purpose,trace and rare earth elements of the sampled mudstones from the Bayingebi Formation of the well Gc1 were studied to discuss the paleoenvironmental dynamics.A comprehensive geochemical analysis with environmental sensitive trace metals(such as V,Ni,Sr,Ba,Cu,Ce _(anom),etc.)indicated that the Bayingebi Formation experienced from a dry-hot to a warm-humid,then to a semi-arid climatic state,and from a saline to a fresh,then to a brackish dysoxic environment.Furthermore,the strong correlation between w(Sr)/w(Cu)and w(Sr)/w(Ba)indicated that the increase in salinity might have been controlled by the proposed arid climate.Combined with sporopollen analysis,the oil-bearing shales of the Bayingebi Formation were considered here to be deposited in a warm and semi-humid climate,promoting organic matter production and preservation.A saline-brackish environment might have also promoted the enrichment of organic matter and the formation of high-quality oil shales.

关 键 词：银额盆地 下白垩统 巴音戈壁组 微量元素地球化学 古环境 

分 类 号：P595[天文地球—地球化学]