| 1 | 深层、超深层碎屑岩储层勘探现状与研究进展显示文摘近年来,随着油气资源增长的需求和勘探理论方法的深入,深达5 000~8 000 m深层、超深层碎屑岩储层日益成为油气勘探的新领域。20世纪70年代末以来,我国对深层、超深层碎屑岩储层的研究已经开展了几十年,取得了一系列重大发现。在我国典型盆地大地构造背景和沉积环境影响下,深层、超深层碎屑岩储层经历了长期的埋藏、压实和溶蚀等作用,通常物性较好而形成有效储层。因此,有效储层形成的主控因素成为深层、超深层碎屑岩领域研究关注的焦点。研究发现:①深部溶蚀作用是深层、超深层碎屑岩有效储层形成的普遍机理,主要通过有机质成熟产生的有机酸和无机酸等对粒间碳酸盐胶结物和长石、岩屑等易溶组分的溶蚀,从而形成次生孔隙。②地温梯度越低,成岩强度越弱,砂岩孔隙度衰减速率越慢;早期长期浅埋、晚期快速深埋的过程能够有效保存原生孔隙。③异常压力能够延缓岩石受到的压实作用,抑制有机酸排出而有利于深层、超深层储层形成次生孔隙。④膏盐层会延缓成岩作用进程,形成物性和压力双重封闭,有利于膏盐层下砂岩孔隙的保存。⑤黏土膜如绿泥石黏土膜等,对深层、超深层碎屑岩储层高孔隙度的保存具有重要贡献。⑥成岩压实作用、早期烃类充注及碎屑颗粒成分等因素也会对有效储层的形成产生影响。对深层、超深层储层油气地质研究,要立足于陆上,加强海洋特别是深水区域油气勘探工作,同时要进一步加强油气地质勘探理论和勘探技术的创新。 | 冯佳睿 高志勇 崔京钢 周川闽 | 2016 | 地球科学进展2016,31,7: | 46 |
| 2 | Characterization of a Lacustrine Shale Reservoir and the Evolution of its Nanopores: A Case Study of the Upper Cretaceous Qingshankou Formation in the Songliao Basin, Northeastern China显示文摘The Songliao Basin is one of the most important petroliferous basins in northern China. With a recent gradual decline in conventional oil production in the basin, the exploration and development of unconventional resources are becoming increasingly urgent. The Qingshankou Formation consists of typical Upper Cretaceous continental strata, and represents a promising and practical replacement resource for shale oil in the Songliao Basin. Previous studies have shown that low-mature to mature Qingshankou shale mainly preserves type Ⅰ and type Ⅱ1 organic matter, with relatively high total organic carbon(TOC) content. It is estimated that there is a great potential to explore for shale oil resources in the Qingshankou Formation in this basin. However, not enough systematic research has been conducted on pore characteristics and their main controlling factors in this lacustrine shale reservoir. In this study, 19 Qingshankou shales from two wells drilled in the study area were tested and analyzed for mineral composition, pore distribution and feature evolution using Xray diffraction(XRD), scanning electron microscopy(SEM), low-pressure nitrogen gas adsorption(N2-GA), and thermal simulation experiments. The XRD results show that clay, quartz, and feldspar are the dominant mineral constituents of Qingshankou shale. The clay minerals are mostly illite/smectite mixed layers with a mean content of 83.5%, followed by illite, chlorite, and kaolinite. There are abundant deposits of clay-rich shale in the Qingshankou Formation in the study area, within which many mineral and organic matter pores were observed using SEM. Mineral pores contribute the most to shale porosity;specifically, clay mineral pores and carbonate pores comprise most of the mineral pores in the shale. Among the three types of organic matter pores, type B is more dominant the other two. Pores with diameters greater than 10 nm supply the main pore volume;most are half-open slits and wedge-shaped pores. The total pore volume had no obvious linear relationship with TOC content, but had some degree of positive correlation with the content of quartz + feldspar and clay minerals respectively. However, it was negatively correlated with carbonate mineral content. The specific surface area of the pores is negatively related to TOC content, average pore diameter, and carbonate mineral content. Moreover, it had a somewhat positive correlation with clay mineral content and no clear linear relationship with the content of quartz + feldspar. With increases in maturity, there was also an increase in the number of carbonate mineral dissolution pores and organic matter pores, average pore diameter, and pore volume, whereas there was a decrease in specific surface area of the pores. Generally, the Qingshankou shale is at a low-mature to mature stage with a TOC content of more than 1.0%, and could be as thick as 250 m in the study area. Pores with diameters of more than 10 nm are well-developed in the shale. This research illustrates that there are favorable conditions for shale oil occurrence and enrichment in the Qingshankou shale in the study area. | ZHANG Xu LIU Chenglin LI Bing WU Linqiang GUI Herong WANG Ziling ZHANG Zhihui LIANG Dexiu | 2020 | Acta Geologica Sinica(English Edition)2020,94,2: | 2 |