可溶有机质对海陆过渡相页岩孔隙结构的定量影响

Quantitative influence of soluble organic matter on pore structure in transitional shale

张琴 梁峰 庞正炼 周尚文 吝文

ZHANG Qin LIANG Feng PANG Zhenglian ZHOU Shangwen LIN Wen

1. 中国地质大学(北京) 能源学院, 北京 100083; 2. 中国石油勘探开发研究院, 北京 100083; 3. 国家能源页岩气研发(实验)中心, 河北 廊坊 065007

1. School of Energy Resources, China University of Geosciences(Beijing), Beijing 100083, China; 2. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China; 3. National Energy Shale Gas R & D(Experimental) Center, Langfang, Hebei 065007, China

为了定量评价可溶有机质在海陆过渡相页岩中对孔隙结构的影响，选取辽河坳陷东部凸起海陆过渡相石炭系太原组典型页岩样品及其对应样品的等分样，进行双氧水氧化可溶有机质处理，并对处理前后的样品分别进行有机碳含量、XRD衍射和低压氮气吸附测试，基于测试结果系统对比，分析可溶有机质对海陆过渡相页岩孔隙结构的影响。结果表明，无机质矿物晶体结构稳定，双氧水对样品处理会消耗可溶有机质并氧化低价铁的化合物（黄铁矿、菱铁矿），使其含量减少，而对其他无机矿物影响较小；海陆过渡相页岩有机质孔整体不发育，可溶有机质以分散的形式充填在无机质矿物孔隙中，充填的可溶有机质占总有机质的53.06%～90.38%，且主要充填在大孔和中孔中；可溶有机质去除后，样品的孔容和比表面积均增加，其累积增加量占原始样品的72.74%～121.83%和32.8%～52.74%。原始有机质含量以及可溶有机质占比是影响样品处理后孔容和孔面积增量的主要影响因素。

Some representative samples of the Taiyuan Formation from the eastern uplift of the Liaohe Depression were selected in order to quantitatively evaluate the influence of organic matter on pore structure in transitional shale. Methods include quantitative mineral analysis by X-ray diffraction (XRD), Rock-Eval pyrolysis, and low pressure nitrogen adsorption. Analyses were performed on aliquot samples in the natural state and after soluble organic matter (SOM) removal by treatment with hydrogen peroxide (H2O2). The results indicated that the crystal structure of inorganic minerals is stable and the SOM removal process oxidizes and decreases or removes pyrite and siderite from the samples. All other inorganic phases remain unaffected. Compared with marine shale, OM pores are undeveloped, and the SOM filled in inorganic pores and matrix in the form of discrete particles or as laminations in the transitional shale samples. The cumulative fraction of total SOM actually held in inorganic pores ranges from 53.06% to 90.38%, and it mainly filled in mesopores and macropores. After SOM removal, the pore volume and pore surface area of samples both increase. The cumulative increase fraction of pore volume ranges from 72.14% to 121.83% and the cumulative increase fraction of pore area ranges from 32.8% to 52.74%. The original TOC content and the SOM proportions control pore volume and pore area increase.

国家科技重大专项（201705035）资助。

https://doi.org/10.11781/sysydz201805730