松辽盆地古龙凹陷白垩系青山口组页岩油储层中微米孔缝特征及油气意义  

Characteristics and significance of micron pores and micron fractures in shale oil reservoirs of Cretaceous Qingshankou Formation in Gulong sag,Songliao Basin

作　　者：何文渊 赵莹 钟建华 孙宁亮[3] HEWenyuan;ZHAO Ying;ZHONG Jianhua;SUN Ningliang(China National Oil and Gas Exploration and Development Company Ltd.,Beijing 100032,China;Heilongjiang Provincial Key Laboratory of Continental Shale Oil,Daqing 163712,Heilongjiang,China;Ocean Engineering Research Institute,Northeastern University,Qinhuangdao 066004,Hebei,China;School of Geosciences,China University of Petroleum(East China),Qingdao 266580,Shandong,China)

机构地区：[1]中国石油国际勘探开发有限公司,北京100032 [2]黑龙江省陆相页岩油重点实验室,黑龙江大庆163712 [3]东北大学海洋工程研究院,河北秦皇岛066004 [4]中国石油大学(华东)地球科学与技术学院,山东青岛266580

出　　处：《岩性油气藏》2024年第3期1-18,共18页Lithologic Reservoirs

基　　金：中国石油天然气股份有限公司科技重大专项“大庆古龙页岩油勘探开发理论与关键技术研究”(编号:2021ZZ10);黑龙江省“百千万”工程科技重大专项“松辽盆地北部古龙页岩油成藏条件及甜点分布规律研究”(编号:2020ZX05A01)联合资助。

摘　　要：通过岩心观察、薄片鉴定、电子背散射、二次成像及能谱分析等多种实验手段,对松辽盆地古龙凹陷白垩系青山口组页岩油储层中的微米孔和微米缝进行了研究。研究结果表明:(1)古龙凹陷页岩油储层岩性为以页岩为主的细粒碎屑岩,矿物成分以黏土和长英质为主,在结构上显示出泥岩或页岩的特点,整体为长英质页岩;储层中微米孔、缝发育,类型多样。(2)研究区微米孔直径一般为1~2μm,最大可达70μm,多呈近圆形、扁圆形、多角形和不规则形,按成因可分为压实应力屏蔽孔、成岩自生孔、溶蚀孔、生排烃扩张孔、有机质孔和硅藻残留孔6类;压实应力屏蔽孔多发育在刚性矿物的两侧;成岩自生孔常发育在白云石、绿泥石、伊利石等成岩自生矿物中,以晶间孔为主;溶蚀孔多发育在碳酸盐矿物中,内部可见次生菌丝状絮凝体;生排烃扩张孔多呈垂直或近垂直成列产出,与轻质油形成的二次生烃和排烃有关;有机质孔发育在有机质内部,与植物的残留细胞及轻质油和天然气的充填有关;硅藻残留孔主要发育在硅藻内部和边缘,孔径较大,一般为数微米至数十微米。(3)研究区微米缝以顺层为主,宽一般为1~10μm,最大可达100μm,长主要为数微米至数十微米,可见毫米级;可分为成岩收缩缝、溶蚀缝、生排烃扩张缝和构造/剪切缝4类,成岩收缩缝以张性缝为主,缝弯曲,缝壁参差不齐;溶蚀缝宽度可达60~70μm,裂缝内可见自生黏土,缝两侧有黄铁矿、磷灰石和白云石等自生矿物;生排烃扩张缝两侧多锯齿状参差不齐,绕过刚性矿物;构造/剪切微米缝一般平直,有与剪切相关的其他裂缝伴生。(4)研究区不同尺度的孔、缝之间连通性较好,形成了“纳米孔+纳米缝、微米孔+微米缝、毫米孔+毫米缝”三级储集和输导体系。By means of core observation,thin section identification,electron backscattering,secondary imaging and energy spectrum analysis,the micron pores and micron fractures in shale oil reservoirs of Cretaceous Qingshankou Formation in Gulong sag of Songliao Basin were studied.The results show that:(1)The lithologies of shale oil reservoirs in Gulong sag are fine-grained clastic rocks dominated by shale,and the mineral composition is mainly clay and felsic,showing the characteristics of mudstone or shale in structure,and the whole reservoir is felsic shale.Micron pores and micron fractures are developed in reservoirs with various types.(2)The diameter of micron pores in the study area is generally 1-2μm,and the maximum can reach 70μm,and they are nearly round,oblate,polygonal and irregular.According to the genesis,they can be divided into six types:compaction stress shielding pores,diagenetic authigenic pores,dissolved pores,hydrocarbon generation and expulsion expansion pores,organic matter pores and diatom residual pores.Compaction stress shielding pores are mostly developed on both sides of rigid minerals.Diagenetic authigenic pores are often developed in authigenic minerals such as dolomite,chlorite and illite,mainly intergranular pores.Dissolved pores are mostly developed in carbonate minerals,and secondary mycelial floccules can be seen inside.Hydrocarbon generation and expulsion expansion pores are mostly produced in vertical or nearly vertical rows,which is related to the secondary hydrocarbon generation and expulsion formed by light oil.Organic matter pores develop in organic matter and are related to residual cells of plants and filling of light oil and natural gas.Diatom residual pores mainly develop in the interior and edge of diatoms,with large sizes ranging from several microns to tens of microns.(3)The micron fractures in the study area are mainly bedding,with a width of 1-10μm and a maximum of 100μm,and a length of several microns to tens of microns.They can be divided into four types:diagenetic shri

关 键 词：微米孔 微米缝 储集空间 连通性 页岩油储层 青山口组 白垩系 古龙凹陷 松辽盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探] P618.13[天文地球—矿床学]