AUTHOR=Yan Wenyuan , Zha Ming , Qu Jiangxiu , Ding Xiujian , Zhang Qinglan 

TITLE=Deformation Bands and Associated FIP Characteristics From High-Porous Triassic Reservoirs in the Tarim Basin, NW China: A Multiscale Analysis

JOURNAL=Frontiers in Earth Science

VOLUME=Volume 9 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2021.743157

DOI=10.3389/feart.2021.743157

ISSN=2296-6463

ABSTRACT=Deformation bands are widely formed and distributed in Triassic high-porous rocks as a result of multi-stage tectonic movement. In this research, core observation, the rock thin section (fluorescence and casting thin section), FIB-SEM, X-ray Diffraction, Laser Raman, and thermometry of fluid inclusions were employed to describe the macro and micro characteristics of deformation bands and associated relationship with microfractures. Results indicate that the main types of deformation bands formed in Lunnan Triassic high porosity sandstone during Yanshanian and Himalayan periods under different temperature and pressure conditions are compaction shear bands, its quantity increases evidently with the distance of thrust faults. The density of deformation bands near the fault is about 15/m, porosity and permeability decrease sharply compared with that of the host rock. Microscopically, two obtained fluid-inclusion-planes (FIP) can be distinguished as 51 samples collected from 12 wells by the cutting relationship and mechanical characteristics. The homogenization temperature of associated aqueous inclusion is generally characterized by two peaks, mainly 70-80℃ and 110-120 ℃, which were formed in the Late Yanshanian and late Himalayan periods. The formation period of deformation bands induced by the intragranular microfractures, improved the reservoir seepage capacity. In the later stage, as the interlayer and barrier with low porosity and low permeability affects the distribution of oil and gas, which is an important factor in this study of local fluid dynamic field and high-quality reservoir evolution distribution.