Xin Li

Xinjiang University · School of Geology and Mining Engineering

The microstructure of coal, such as matrix morphology, pore structure and carbon structure, is of great significance to the resource enrichment in coal and the study of graphitization. In this work, atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM) were employed to characterize microstructure of cores from t...

Numerical simulation is an efficient method to quantitatively describe the reservoir dynamics of coalbed methane (CBM) reservoirs. The ideal steeply inclined model (ISIM), assumed to be a steeply inclined plate, has been widely applied in steep coalbed methane reservoir modeling, although the ISIM cannot accurately reflect the actual reservoir geol...

Studies on permeability under pyrolysis temperatures (PTs) can provide instructions for syngas production of underground coal gasification (UCG). Permeability variations of lignite, high volatile bituminous coal (HVBC) and medium volatile bituminous coal (MVBC) under elevated PTs (35°C–600 °C) were studied. Structure and weightlessness as well as m...

Nanoparticles (NPs) in the Earth surface systems have been a global concern due to their abnormal effects and their scientific significance and application value in environmental remediation and resource exploration. By means of comparative and comprehensive studies: (1) A description of the development of techniques for detecting NP characteristic...

Water sensitivity (WS) and salinity sensitivity (SS) are key issues to be investigated for instructing coalbed methane (CBM) production. This work studied the influences of minerals and pores on WS and SS of medium-volatile bituminous coal (MVBC) and highly volatile bituminous coal (HVBC) deposited in northwestern China by detecting and observing m...

Water in coal pores can generate strong steam explosions when treated with microwave irradiation. In order to improve the sensitivity of coal reservoirs to microwaves, we used varying concentrations of NaCl on the pore solution, which further increased the effect of microwaves on permeability enhancement. In our experiments, we selected 3 ratios of...

Microwave heating of water-bearing coal can promote pore water evaporation. The pores are broken under the action of steam pressure, increasing the permeability of the coal. This study is aimed at investigating the mechanism of permeability improvement of water-bearing coal rock by microwave steam explosion. First, a microwave oven was used to irra...

Water-based fracturing is applied for stimulating coal reservoir. However, invasion of water can result in low flowback efficiency and low coalbed methane (CBM) yield. Nitrogen injection is an effective method to enhance CBM production. In this study, nitrogen displacing water experiments using water saturated high volatile bituminous coal were con...

Studying on the pore size distribution of coal is vital for determining reasonable coalbed methane development strategies. The coalbed methane project is in progress in the southern Junggar Basin of northwestern China, where high volatile bituminous coal is reserved. In this study, with the purpose of accurately characterizing the full-scale pore s...

The large spatial variability of in-situ stress and initial reservoir pressure in steeply-dipping ultra-thick coalbed methane (UTCBM) reservoirs exert strong control on the initial distribution of stress-sensitive permeability. This results in significant differences in the propagation of reservoir depressurization, gas production characteristics,...

The Shanganning Carbonate Platform (SCP) of the North China Craton (NCC) was located in the Trade Winds belt during the Cambrian, which influenced its facies development. In recent years, numerous drillcores have been recovered from these units, but the depositional environments and facies architecture of this large (~2.0 × 10⁵ km²) carbonate platf...

Distinguishing the differences of pore characters between different mixed lithofacies shales is helpful for improving shale gas development efficiencies. In this study, the targeted Longmaxi shale (L1) of the Southern Sichuan Basin was selected as the research object. Two kinds of mixed lithofacies shale were identified by analyzing total organic c...

High volatile bituminous coal (HVBC) reservoirs are now regarded as one of the most important targets for coalbed methane (CBM) exploration and development in northwestern China. Water invasion during coalbed methane reservoir fracturing can induce water blockage damage, leading to decreased relative permeability of gas and reduced production of CB...

Nitrogen injection is an effective way to improve coalbed methane (CBM) recovery, but there are few studies of the regularity of fluid flow during nitrogen injection. To study the flow of methane and water during nitrogen injection into coal reservoirs, a high-volatile bituminous B coal from the southern margin of the Junggar Basin, Xinjiang and a...

To investigate the physical properties of anthracite reservoirs with different metamorphic grades (Ro,max), 38 anthracite samples with an Ro,max value between 2.5 and 4.2% from the Guxu and Jincheng mining areas in China were selected to conduct proximate analysis and determine the macerals, pore size distribution, adsorption capacity, in-situ gas...

Coalbed methane (CBM) development is in progress in northwestern China, where there are deposits of medium volatile bituminous coal (MVBC) and high volatile bituminous coal (HVBC). Stress sensitivity can lead to low gas-production during CBM development. In this study, three groups of HVBC samples and one group of MVBC samples are applied for low-f...

Exploitation of coalbed methane (CBM) involves groundwater extraction to depressurize coal reservoirs. This can involve groundwater extraction from multiple coal seams (commingled drainage). Interlayer interferences, caused by heterogeneity of hydrodynamic fields of the different coal gas reservoirs, can restrain CBM production. Understanding of th...

Coalbed methane (CBM) reserve of low-rank coal (Ro,max < 0.65), occupying a proportion of more than 40% of the total CBM reserve of China, is 14.7 × 1012 m3. The exploration degree, particularly in situ gas content estimation of low-rank CBM reservoirs in China, is extremely low. Meanwhile, adsorption characteristics of low-rank coal reservoirs hav...