Shale oil enrichment evaluation and production law in Gulong Sag, Songliao Basin, NE China

作者：Longde SUN, Baowen CUI, Rukai Zhu, Rui Wang, Zihui Feng, Binhui LI, Jingya Zhang, Bo Gao, Qingzhen WANG, Huasen Zeng, Yuanhui LIAO, Hang Jiang · 发表于：Petroleum Exploration and Development · 年份：2023 · DOI：10.1016/s1876-3804(23)60406-9 · 被引用次数：83 · 研究领域：Hydrocarbon exploration and reservoir analysis、NMR spectroscopy and applications、Atmospheric and Environmental Gas Dynamics

Based on the results of drilling, tests and simulation experiments, the shales of the Cretaceous Qingshankou Formation in the Gulong Sag of the Songliao Basin are discussed with respect to hydrocarbon generation evolution, shale oil occurrence, and pore/fracture evolution mechanism. In conjunction with a substantial amount of oil testing and production data, the Gulong shale oil enrichment layers are evaluated and the production behaviors and decline law are analyzed. The results are drawn in four aspects. First, the Gulong shales are in the stage of extensive hydrocarbon expulsion when Ro is 1.0%–1.2%, with the peak hydrocarbon expulsion efficiency of 49.5% approximately. In the low–medium maturity stage, shale oil migrates from kerogen to rocks and organic pores/fractures. In the medium–high maturity stage, shale oil transforms from adsorbed state to free state. Second, the clay mineral intergranular pores/fractures, dissolution pores, and organic pores make up the majority of the pore structure. During the transformation, clay minerals undergo significant intergranular pore/fracture development between the minerals such as illite and illite/smectite mixed layer. A network of pores/fractures is formed by organic matter cracking. Third, free hydrocarbon content, effective porosity, total porosity, and brittle mineral content are the core indicators for the evaluation of shale oil enrichment layers. Class-I layers are defined as free hydrocarbon content equal or greater than ...