东海丽西洼陷缓坡带中-下古新统成岩演化  

Diagenetic evolution of Middle-Lower Paleocene sandstone reservoirs in gentle slope zone of Lixi Sag,East China Sea Shelf Basin

作　　者：汤睿 覃军 黄山 常文琪 董哲 田钧名 TANG Rui;QIN Jun;HUANG Shan;CHANG Wenqi;DONG Zhe;TIAN Junming(Shanghai Branch of CNOOC(China)Ltd.,Shanghai 200335,China;College of Energy,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]中海石油(中国)有限公司上海分公司,上海200335 [2]成都理工大学能源学院,成都610059

出　　处：《海洋地质前沿》2023年第9期46-54,共9页Marine Geology Frontiers

基　　金：中国海油“七年行动计划”东海专项“丽水凹陷在生产气田保产及新领域勘探开发关键技术研究”(CNOOC-KJ135 ZDXM 39 SH02)。

摘　　要：丽西洼陷的储层品质是长期以来制约勘探的关键要素之一。为了分析丽西洼陷缓坡带新的勘探层系-中-下古新统的有效储层发育问题,综合利用岩石薄片鉴定、扫描电镜(SEM)分析、X衍射分析、镜质体反射率测定、流体包裹体分析等技术,研究了丽西洼陷缓坡带中-下古新统的储层成岩演化特征。研究表明,丽西洼陷缓坡带中-下古新统成岩演化具有南北差异性,总体上现今南部演化程度高于北部。在斜坡的主体部位(斜坡中带),南部中-下古新统可进入中成岩B期,而北部中-下古新统总体处于中成岩A期。通过实验现象及结果分析,本研究认为影响原生粒间孔隙保存的2大关键要素为刚性颗粒含量和浅埋藏时碳酸盐沉淀;影响次生溶蚀孔形成的2大关键要素为地表酸性水、幔源二氧化碳和烃源岩演化排出的酸等形成的3类酸性环境,以及岩石早-中期碳酸盐含量和长石含量。The reservoir quality of Lixi Sag is one of the key factors restricting petroleum exploration for a long time.To study the development of effective reservoirs in Middle-Lower Paleocene in the gentle slope zone of the Lixi Sag,its diagenetic evolution was analyzed using thin sections,scanning electron microscope(SEM),X-ray diffraction,vitrinite reflectance and fluid inclusions of reservoir sandstone in some typical wells.Results shows that the diagenetic evolution of the Middle-Lower Paleocene in the gentle slope zone of Lixi Sag is different from north to south.In general,the evolution of the southern Lixi Sag is slightly more mature than that of the northern.In the main part of the slope(mid slope),the Middle-Lower Paleocene reservoir sandstone in the south had reached the middle diagenetic stage B,whereas in the north it only reached the middle diagenetic stage A.The content of rigid particles and carbonate precipitation in shallow burial depth are two key factors for the preservation of primary intergranular pores.The acidic environment formed by surface acidic water,mantle derived carbon dioxide,and acid discharged from the evolution of hydrocarbon source rocks,together with two types of acid soluble minerals,i.e.,carbonate and feldspar,are key factors for the formation of secondary dissolution pores.

关 键 词：储层成岩演化 中-下古新统 缓坡带 丽西洼陷 

分 类 号：P744.4[天文地球—海洋科学] P736