Lithology and Lithofacies Identification of Permian Volcanic Rocks in Southwestern Sichuan

Long Zhang ； Cheng Yin ； Peng Jiang

《International Core Journal of Engineering》 8卷1期 (2022/01) Pp. 574-579

https://doi.org/10.6919/ICJE.202201_8(1).0079

摘要

At the end of 2018, the Yongtan 1 well drilled by petrochina Southwest Oil and Gas Field Company in southwest Sichuan Basin encountered thick volcanic rocks and industrial gas flow in volcanic breccia lava, indicating that the Permian volcanic rocks in Sichuan Basin have broad exploration prospects. In order to further clarify the exploration prospect of Permian volcanic gas reservoir in western Sichuan, the characteristics and controlling factors of volcanic clastic reservoir in this area are systematically studied by means of geology, logging, geophysics and other techniques, and the exploration potential of natural gas in this area is discussed.(1) The log response shows that the volcanic rocks in Well Yongtan 1 can be divided into volcanic lava, pyroclastic lava and pyroclastic lava. The lithofacies is mainly pyroclastic eruption facies and basalt overflow facies. (2). The seismic facies model of volcanic rocks was established based on seismic response characteristics, and volcanic mechanism identification and volcanic facies characterization were carried out. Three types of seismic facies models can be identified: eruption facies, overflow facies and volcanic channel facies. (3). The identification and characterization of volcanic lithofacies and volcanic mechanism are carried out by extracting a variety of seismic attributes and optimizing the volcanic rock sensitive root mean square amplitude attribute, coherent body attribute and other attributes through attribute clustering and attribute fusion. (4). Reservoir prediction of volcanic rocks is carried out through wave impedance inversion. A comprehensive analysis of the results shows that the lithology and lithofacies identification by geophysical method is consistent with the subsequent drilling, which can be used as a guide for the subsequent volcanic work.

關鍵字

Olcanic Rocks ； In-Dustrial Gas ； The Permian Volcanic Rocks ； Basalt Overflow Facies

參考文獻

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