细粒沉积岩有机质-矿物-孔隙在升温过程中的变化及其规律——以沧东凹陷孔二段为例  

Changes and regularities of organic matter mineral pore in fine-grained sedimentary rocks during temperature rise:A case study of fine-grained sedimentary rocks in kong 2 member of Cangdong sag

作　　者：尹玲芝 蒲秀刚[2] 陈世悦[1] 鄢继华[1] 张伟[2] YIN Lingzhi;PU Xiugang;CHEN Shiyue;YAN Jihua;ZHANG Wei(School of Geosciences and Technology,China University of Petroleum(East China),Qingdao 266580,Shandong Province,China;Research Institute of Exploration and Development of Dagang Oilfield,PetroChina Company Limited,Tianjin 300280,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]中国石油天然气股份有限公司大港油田勘探开发研究院,天津300280

出　　处：《浙江大学学报（理学版）》2023年第5期597-606,共10页Journal of Zhejiang University（Science Edition）

基　　金：国家自然科学基金资助项目(41572087).

摘　　要：在埋藏过程中,随着埋深的增加,细粒沉积岩的矿物组成、有机质形态、孔隙类型与质量分数等会发生一系列变化。为揭示其变化规律,对有机质热模拟的残样进行了扫描电镜、全岩X射线衍射、镜质体反射率(Ro)、岩石热解、有机碳质量分数等测试。发现在从室温(25℃)到550℃的升温过程中,有机质形态由团块状向条带状、团块状变化;黏土矿物由层片状逐渐向絮状转化;碳酸盐矿物溶蚀加剧,温度超过500℃后,出现溶蚀-沉淀现象;随着温度的升高,由有机质热演化产生的有机质孔的面积不断增加,在450~475℃时,有机质孔孔径达最大,当温度高于475℃后,有机质孔的数量增多、孔径缩小;由于随着温度的升高黏土矿物由蒙脱石向伊蒙混层再向伊利石转化,导致其晶间孔先缓慢增加后迅速增加最后趋于稳定;溶蚀孔主要由长石和碳酸盐矿物产生,与有机质热演化产生的有机酸密切相关,溶蚀孔的变化趋势与有机质孔的变化趋势基本一致,先缓慢增加后迅速增加随后又缓慢下降趋于稳定。当温度为450~475℃时,孔隙数量达最多、孔径最大,形成良好的储层。During the burial process of fine-grained sedimentary rocks,with the increase of burial depth,a series of changes will occur in their mineral composition,organic matter morphology,pore type and content.In order to deeply reveal the characteristics of these changes,we tested the residual samples of organic matter thermal simulation by scanning electron microscopy,whole rock X-ray diffraction,vitrinite reflectance(Ro),rock pyrolysis and organic carbon content.It was found that the forms of organic matter changed from lump-banded to lump-like when the temperature increased from room temperature to 550℃.Clay minerals gradually transformed from lamellar to flocculent;the dissolution of carbonate minerals was dramatic,and the dissolution-precipitation phenomenon occured when the temperature was higher than 500℃.With the increase of temperature,the area of organic pores produced by thermal evolution of organic matter increased continuously.At 450-475℃,the organic pores reached the maximum,but when the temperature is higher than 475℃,the number and pore size of organic pores will decrease.As the clay minerals transformed from montmorillonite to illite-montmorillonite mixed layer and then to illite following the increase of temperature,the intergranular pores of clay minerals increase slowly at first,then increased rapidly and finally tended to be stable.The dissolution pores were mainly produced by feldspar and carbonate minerals,which were closely related to the organic acids produced by the thermal evolution of organic matter.Therefore,the change trend of dissolution pores is basically the same as that of organic matter pores,which increases slowly first and then increases rapidly,and then decreases slowly and tends to be stable.So the temperature range of 450-475℃,during which the number of pores and pore size are the largest,is a good reservoir.

关 键 词：细粒沉积岩 热模拟 有机质 矿物 孔隙 

分 类 号：TE143[石油与天然气工程—油气勘探]