Development mechanism of metamorphic fractured reservoirs in the Bozhong area, Bohai Bay Basin: Implications from tectonic and magmatic hydrothermal activities

作者：Chaoyang Liu, Huiyong Li, Xuanlong Shan, Jian Yi, Peng Xu, Shuyue Ren, Penghui Niu · 发表于：Geoenergy Science and Engineering · 年份：2023 · DOI：10.1016/j.geoen.2023.212030 · 被引用次数：17 · 研究领域：Hydrocarbon exploration and reservoir analysis、Seismic Imaging and Inversion Techniques、Hydraulic Fracturing and Reservoir Analysis

The BZ19-6 condensate gas field is the largest metamorphic gas field of the Bohai Bay Basin in China and contains typical fractured reservoirs within the inner parts of an Archean metamorphic buried hill. However, the mechanisms driving its creation and evolution are not well explored. Based on core and sidewall samples, thin sections, X-ray diffraction (XRD) analysis, U–Pb age dating, fluid inclusions , and imaging logging and seismic data , the lithologies , mineral contents and reservoir characteristics of the inner parts of a metamorphic buried hill were evaluated and then the main factors controlling the fractured reservoir were further explored in the Bozhong area. The results show that the lithology mainly includes granitic gneiss , cataclastic rocks and Mesozoic intrusions, among which the granitic gneiss is widely distributed and contains a large number of light-colored minerals. The reservoir spaces are mainly composed of tectonic fractures (TFs), cleavage fractures (CFs), introduced fractures (IFs) and dissolved pores (DPs). Numerous tectonic fractures provide the main reservoir spaces and can be divided into two groups, namely those with nearly WE- and NS-oriented strikes, which are closely related to the stress fields produced by Indosinian and Yanshan movements, respectively. IFs and DPs were developed by magmatic activities, which occurred during the Mesozoic, while magmatic hydrothermal fluid had an obvious negative impact on reservoir quality, resulting in fr...