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

Liu, Chaoyang; Li, Huiyong; Shan, Xuanlong; Yi, Jiawei; Xu, Peng; Ren, Shuyue; Niu, Penghui

doi:10.1016/j.geoen.2023.212030

Cited by 8 publications

(16 citation statements)

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“…The Bozhong 13-2 oil and gas field has been drilled to reveal that the strata from bottom to top are Archean strata, the Mesozoic strata, the Palaeogene Shahejie and Dongying Formations, the Neogene Guantao and Minghuazhen Formations and the Quaternary Pingyuan Formation (Figure 2). The main strata in this study are Archean basement, and drilling data show that most metamorphic rocks have experienced intrusion [7,12]. The basement buried hill has undergone complex tectonic events-the Indosinian, Yanshanian and Himalayan tectonic movements [7] (Figure 2).…”

Section: Geological Settingmentioning

confidence: 85%

“…The main strata in this study are Archean basement, and drilling data show that most metamorphic rocks have experienced intrusion [7,12]. The basement buried hill has undergone complex tectonic events-the Indosinian, Yanshanian and Himalayan tectonic movements [7] (Figure 2). Among them, the Indosinian and Yanshanian tectonic movements largely controlled the Bozhong structural belt [30,31].…”

Section: Geological Settingmentioning

confidence: 85%

“…Located in the central and eastern parts of the Bohai Bay Basin, the Bozhong Sag is the largest oil-rich sag in the Bohai Bay Basin, with an area of approximately 1 × 10 4 km 2 bounded by the Bodong low uplift to the east, the Shaleitian uplift to the west, the Shijiutuo uplift to the north, and the Bonan low uplift to the south [27] (Figure 1b). The Bozhong Sag experienced vertical uplift of the basement before the Indosinian period, and the basic outline of the buried hill in the Archean strata was formed by early Indosinian thrust compression [7,8,12,20].…”

Section: Geological Settingmentioning

confidence: 99%

“…Buried hill oil and gas reservoirs are usually located in the crystalline basement of the basin [7,8], and generally have the characteristics of large burial depth, large reservoir thickness and strong reservoir heterogeneity [1,8]. The controlling effect of fractures on basement reservoirs in basins has been widely recognized [2,3,9,10].…”

Section: Introductionmentioning

confidence: 99%

“…The controlling effect of fractures on basement reservoirs in basins has been widely recognized [2,3,9,10]. Metamorphic rocks have almost no primary pore space [11] and often experience multi-stage metamorphism and tectonism [7]. Fractures play a fundamental role in the formation of large-scale metamorphic buried hill reservoirs [8].…”

Section: Introductionmentioning

confidence: 99%

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Characteristics, Controlling Factors and Reservoir Quality Implications of Inner Fracture Zones in Buried Hills of Archean Covered Metamorphic Rock in Block 13-2, Bozhong Depression

Lu,

Shan,

et al. 2024

Energies

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Inner fracture zones play a decisive role in the formation of high-quality reservoirs in buried hill reservoirs in covered metamorphic rock. Based on core, sidewall core, thin section, seismic, logging and reservoir physical property data, the fracture development characteristics of the Bozhong 13-2 block buried hill reservoir are described in detail and the controlling factors and the influence on reservoir quality are discussed. The results showed: (1) three groups of tectonic fractures developed in the study area—near-EW-striking, ENE-striking and nearly N–S-striking fractures—were controlled by the early Indosinian thrusting, the late Indosinian to early Yanshanian sinistral strike-slipping and the late Yanshanian late dextral strike-slipping in the Bohai Bay Basin, respectively. The ENE- and nearly-E-W-striking fractures are the most common, and the dip angles of the fractures are mostly between 35° and 75° and thus oblique. (2) The Indosinian-early Yanshanian was the main fracture-forming period, and the dextral strike-slip action in the late Yanshanian was the key to maintaining effective fractures. Imaging logging shows that 97.87% of the fractures are effective fractures. Based on thin section observation, 14.47% of the fractures are unmodified open fractures and 80.37% of the fractures are effective fractures due to reactivation. (3) The late Yanshanian strike-slip fault transformed the deformation adjustment zone formed by the early Indosinian thrust faulting and the core of the fold structure was more conducive to fracture development. The fracture density of a single well located within the deformation adjustment zone and at the core of the fold is between 0.93–1.49 m−1, the fracture density of a single well located only at the core of the fold is between 0.67–0.75 m−1 and that of a single well located at the wing of the fold is between 0.35–0.59 m−1. Diabase dike intrusions promoted the development of local fractures. (4) Fractures promote the migration and accumulation of oil and gas, and the fracture density in the oil layer is between 0.81–2.19 m−1. That in the nonoil layer is between 0.25–1.12 m−1. In addition, fractures not only provide storage space but also effectively improve the reservoir capacity of the inner fracture zones of buried hill reservoirs by concentrating dissolution.

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Section: Geological Settingmentioning

confidence: 85%