Jiao W.-W.,Chongqing Institute of Geology and Mineral Resources |
Yue F.,Chongqing Institute of Geology and Mineral Resources |
Cheng L.-J.,Chongqing Institute of Geology and Mineral Resources |
Ma Y.,China University of Petroleum - Beijing |
Liu G.-M.,Chongqing Institute of Geological Survey
Natural Gas Geoscience | Year: 2015
The pore types and structures are critical to gas bearing capacity of shale reservoirs. Conventional scanning electron microscope, argon ion polishing, high resolution power scanning electron microscope are used to describe pore system of Lower Cambrian Niutitang Formation shale in Southeast Chongqing and discuss the relationship between pore characteristics and gas bearing capacity. There are four categories and nine classes matrix pores and three categories and four classes natural fractures in Lower Cambrian Niutitang Formation shale. Intragranular pore, dissolved pore, high angle shear fracture and low angle decollement fracture constitute the pore system of Lower Cambrian Niutitang Formation shale jointly. The pore system has the characteristics of various types, small pore diameter, poor connectivity and low permeability. Pore volume is mainly provided by the nanoscale pores. No organic pores, poor pore connectivity and regional developed decollement fractures maybe the reason why the Niutitang Formation shale has poor gas-bearing capacity. ©, 2015, Science Press. All right reserved.
Zou J.,Chongqing Institute of Geology and Mineral Resources |
Liu D.,Chongqing Institute of Geology and Mineral Resources |
Tian H.,Chongqing Institute of Geology and Mineral Resources |
Li T.,Chongqing Institute of Geology and Mineral Resources |
And 2 more authors.
International Journal of Coal Science and Technology | Year: 2014
The rare earth elements and yttrium (REY) of the K2 coal from the Moxinpo mine, Chongqing, were determined using inductively coupled plasma mass spectrometry (ICP-MS). The results show that REY are enriched in the K2 coal, with the average content up to 462 μg/g, much higher than average values of most coals in the world. The REY distribution patterns indicate that the light REY is enriched and show a well-pronounced Eu minimum. The fractionation of individual light-REY is higher than that of the heavy-REY. The REY distribution through the K2 coal seam shows that the top and bottom portion of the coal seam have a lower content of REY than the middle portion. Goyazite and rhabdophane were identified with a scanning electron microscope equipped with an energy-dispersed X-ray spectrometer (SEM-EDX). The REY distributions through the coal seam, SEM-EDX data and the correlation analysis between ash yields and the concentrations have revealed that the REY mainly occurs in the organic matter. The K2 coal is a potential rare-metal resource due to its high REY contents, and the coal ash could be regarded as a new and promising raw material for recovery of REY as a by-product. © 2014, The Author(s).
Zhao X.,Chengdu Institute of Geology and Mineral Resources |
Hu C.,ChongQing Institute of Geological Survey |
Ling X.,Chengdu Institute of Geology and Mineral Resources |
Li J.,Chengdu Institute of Geology and Mineral Resources
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2015
The composition of REE in ore bearing rocks of Nanchuan-Wulong area indicates that the total amount of REE is high, and the partition modes in the bauxite-bearing horizons and in the underlying Silurian Hanjiadian Formation are quite consistent. This implies a genetic relationship between the bauxite source and Hanjiadian Formation. The values of LREE /HREE are great in the majority samples. It is obvious that the light rare earth elements are strongly enriched; while the heavy rare earth elements are depleted to varied degrees with Eu middle negative anomaly. The content of REE in the ore bearing rocks changed only slightly after deposition. Based on the characteristics of rare earth elements and the related parameters, the environment of bauxite ore bearing rock series and their material sources are deduced as followings: ore bearing rocks were formed mainly in continental facies with some marine sediments; based on Ce, Eu anomalies, acidity of paleo water media was weak; ore bearing rock series were mainly formed in an oxidation environment, which was profitable for the formation of bauxite. Material sources of the ore bearing rock series are diversified; both silty shale of Silurian Hanjiadian Formation and Carboniferous limestone of Huanglong Formation might be the source of material. © 2015, Jilin University Press. All right reserved.