Mineral-controlled nm-μm-scale pore structure of saline lacustrine shale in Qianjiang Depression, Jianghan Basin, China
2018; Elsevier BV; Volume: 99; Linguagem: Inglês
10.1016/j.marpetgeo.2018.10.016
ISSN1873-4073
AutoresYuxiang Zhang, Qinhong Hu, Shengxiang Long, Jianhua Zhao, Nyujia Peng, Haitao Wang, Xiang Lin, Mengdi Sun,
Tópico(s)Hydraulic Fracturing and Reservoir Analysis
ResumoThe pore structure of the saline lacustrine shales in the Eq3 unit of the Qianjiang Formation was characterized for pore space of μm-nm scales through a combined study of mercury injection capillary pressure (MICP) and small/ultra-small angle neutron scattering (SANS and USANS). X-ray diffraction (XRD) and total organic carbon (TOC) content tests, as well as field emission-scanning electron microscopy (FE-SEM) imaging, are also employed to obtain the mineralogical composition, organic richness, as well as the general pore types and sizes of the selected Qianjiang shale samples. In these samples, three major rock types are identified: (1) silica-rich carbonate mudstone; (2) carbonate/siliceous mudstone; and (3) salt. The porosity, as well as pore size and pore-throat size distributions, generated from both SANS/USANS and MICP techniques indicate a porous rock matrix and well-connected pore networks in the two mudstone rock types. Meanwhile, an averaged TOC of around 3.5 wt% for Eq3 unit exhibits a good quality for oil generation potential. This study primarily provides new insights into the pore structure of the Qianjiang shales across a wide measurable range for both pore and pore-throat sizes, and correlates the pore structure and mineral compositions at different scales.
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