He Wenyuan, Wang Min, Wang Xin, Meng Qi'an, Wu Yan, Lin Tiefeng, Li Jinbu, Zhang Jinyou
Daqing Oil Field Company, Daqing 163712, Heilongjiang, P. R. China.
School of Geosciences, China University of Petroleum (East China), Qingdao 266580, Shandong, P. R. China.
ACS Omega. 2022 Sep 28;7(40):35755-35773. doi: 10.1021/acsomega.2c03804. eCollection 2022 Oct 11.
A major historical breakthrough has been made in the exploration of the GK (the first member of the Qingshankou Formation (K2qn), Gulong Sag) shale oil of the Songliao Basin. However, few reports have been reported on the pore structure characteristics of this large-scale lacustrine medium-high maturity shale. In addition, the difference between the pore structure characteristics of the GK shale and medium-low maturity marine/continental shale is unknown, and the affecting factors of pore development are still unclear. Therefore, in order to clarify the pore structure characteristics of the GK shale and its affecting factors, this study characterized them experimentally and revealed the law of pore evolution using the mineral composition and geochemical analysis, microscopic observations, and pore quantification techniques. Results indicate that (1) the pore system of GK shale reservoirs is divided into micropores (pore diameter < 10 nm), mesopores (10 nm < pore diameter < 50 nm), and macropores (pore diameter > 50 nm); (2) the pore structure of the GK shale is mainly affected by the clay content, siliceous mineral content, and thermal maturity; and (3) when the content of clay minerals and siliceous minerals in the GK shale reservoir is high, and ∼0.8% < < ∼1.4%, the storage capacity and oil content of the GK shale show high values, and it can be considered as a strong candidate for further exploration and development. This research can push the shale oil revolution to a new height and is significant to promote the development of the petroleum industry.
松辽盆地古龙凹陷青山口组（K2qn）第一段页岩油勘探取得了重大历史性突破。然而，关于这种大规模湖相中等成熟度页岩孔隙结构特征的报道较少。此外，GK页岩与中低成熟度海相/陆相页岩孔隙结构特征的差异尚不清楚，孔隙发育的影响因素仍不明确。因此，为了阐明GK页岩的孔隙结构特征及其影响因素，本研究通过实验对其进行了表征，并利用矿物组成和地球化学分析、显微镜观察和孔隙定量技术揭示了孔隙演化规律。结果表明：（1）GK页岩储层孔隙系统分为微孔（孔径<10nm）、中孔（10nm<孔径<50nm）和大孔（孔径>50nm）；（2）GK页岩的孔隙结构主要受黏土含量、硅质矿物含量和热成熟度影响；（3）当GK页岩储层中黏土矿物和硅质矿物含量较高，且0.8%<<1.4%时，GK页岩的储集能力和含油率较高，可作为进一步勘探开发的有力候选对象。本研究可将页岩油革命推向新高度，对推动石油工业发展具有重要意义。
