松辽盆地古龙凹陷青山口组生排烃扩张微米孔/缝的发现及其意义  

Study on expansion-induced micropores and fractures of hydrocarbon generation and expulsion in shale oil reservoir of Qingshankou Formation in Gulong Sag,northern Songliao Basin

作　　者：何文渊 白雪峰 张金友 赵莹 刘召 钟建华 孙宁亮[3,4,6] HE Wenyuan;BAI Xuefeng;ZHANG Jinyou;ZHAO Ying;LIU Zhao;ZHON Janhua;SUN Ningliang(China National Oil and Gas Exploration and Development Company Ltd.(CNODC),Beijing,100034;National Key Laboratory of Green Exploitation of Continental Shale Oil with Multi-Resource Collaboration,Daqing,Heilongjiang,163002;School of Resources&Materials,Northeastern University at Qinghuangdao,Qinghuangdao,Hebei,066004;National Engineering Research Center of Offshore Oil and Gas Exploration,Beijing,100028;School of Geosciences,China University of Petroleum(Eastern China),Qingdao,Shandong,266580;Institute of Ocean Engineering,Northeastern University at Qinhuangdao,Qinhuangdao,Hebei,066004)

机构地区：[1]中国石油国际勘探开发有限公司,北京100034 [2]多资源协同陆相页岩油绿色开采全国重点实验室,黑龙江大庆163002 [3]东北大学秦皇岛分校资源与材料学院,河北秦皇岛066004 [4]海洋油气勘探国家工程研究中心,北京100028 [5]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [6]东北大学海洋工程研究院,河北秦皇岛066004

出　　处：《地质论评》2024年第3期1159-1191,共33页Geological Review

基　　金：国家自然科学基金资助项目(编号:42072138,41572088);中国石油天然气股份有限公司重大科技专项“大庆古龙页岩油勘探开发理论与关键技术研究”项目(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”项目(编号:2020ZX05A01)的成果。

摘　　要：笔者等通过电子背散射、二次成像和能谱分析,结合薄片和反射显微镜观察,发现松辽盆地古龙凹陷青山口组页岩中发育了大量由生排烃扩张形成的微米孔和微米缝。生排烃高压扩张微米孔的特点有:①一般只发育在超高压的页岩油储层中;②一般只发育在黏土质长英页岩中,纯黏土岩少见;③多为近圆形或半圆形,直径多在0.5μm到数微米,一般1~2μm,最大可达8μm;④孔缘一般为以绿泥石为主的黏土,形成不连续的圈环;圈环上缘的黏土多呈弧形或眉状,绿泥石化明显,在背散射图像中呈亮色;⑤孔内多有自生的纳米级葡萄状或豆渣状黏土,是构成封存油气的物质基础;⑥生排烃高压扩张微米孔可以组合成4种类型:即垂向联结成垂直的排烃烟囱型、垂向联结成倾斜的排烃烟囱型、水平联结成顺层的排烃管型和竖面上联结成更大的片状大孔型。排烃烟囱直或微曲,直立或倾斜;宽1~3μm,最宽可达200μm;高十几到30μm,最大可达1500μm;顶部多与顺层微米缝(或毫米缝)联结,是排烃烟囱的最终泄压和泄油气的总库;生排烃扩张微米孔孔隙度变化大,面孔率一般在5%~6%,局部面孔率最高可达39.66%。生排烃高压扩张微米缝的特点有:①一般只发育在超高压的页岩油储层中;②一般只发育在黏土质长英页岩中,纯黏土岩少见;③多以顺页理为主的微米缝为主;④略曲的张性缝,多呈锯齿状,绕过刚性矿物;⑤宽度多在0.5μm到数十微米;最宽可达150μm;⑥多与黄铁矿、白云石、磷灰石等自生矿物伴生;⑦多与生排烃扩张微米孔和排烃烟囱相连。生排烃扩张微米孔缝的形成动力主要有两种:一种是烃类流体的高压扩张力;第二种是烃类流体的化学溶蚀力。笔者等计算了形成这种生排烃微米孔和微米缝的压力,形成生排烃扩张微米孔从1500 m的44.74 MPa到2500 m深的74.81 MPa;形成生排烃扩张微米缝的排烃压力稍大,Shale oil of Qingshankou Formation of Upper Cretaceous in Gulong Sag,Songliao Basin.Methods:Based on electron backscattering and secondary imaging,combined with energy spectrum analysis and thin section observation,it is found that a kind of micron pore and micron fissures formed by hydrocarbon generation and expulsion expansion in Qingshankou Formation shale in Gulong Sag.Results:The characteristics of hydrocarbon generation and expulsion high-pressure expansion micron pores are:①generally only developed in ultra-high pressure shale oil reservoirs;②Generally only developed in clay feldspar shale,pure clay rock is rare;③Most of them are nearly circular or semi-circular,with diameters ranging from 0.5 microns to several microns,generally 1~2 microns,but up to 8 microns;④The wall of the hole is generally clay,and the clay on the upper edge is curved or eyebrow shaped,and the chlorite is obvious,so it is bright and eye-catching in the backscatter image;⑤There are many self-generated nanoscale grape-like or soybean residue clay in the hole.⑥high-pressure expansion micron holes for hydrocarbon generation and expulsion can be combined into four types:vertically connected to form vertical hydrocarbon expulsion chimneys;Vertically connected to form a inclined hydrocarbon exhaust chimney;The hydrocarbon exhaust pipes connected horizontally to the bedding form larger lamellar pores in the profile.Straight or slightly curved hydrocarbon exhaust chimney;1~3 microns wide,up to 200 microns wide;High ten to twenty or thirty microns,up to 1500 microns;The top is mostly connected with the micron slit along the bedding,which is the final pressure relief and oil and gas drainage reservoir of the hydrocarbon exhaust chimney.The porosity of hydrocarbon-generating and expelling micron pores varies greatly,generally in the range of 5%~6%.The characteristics of high-pressure expansion micron fractures for hydrocarbon generation and expulsion are:①generally only developed in ultra-high pressure shale oil reservoirs;②Gener

关 键 词：生排烃 扩张 微米孔 微米缝 超高压 古龙页岩 青山口组 

分 类 号：P618.13[天文地球—矿床学]