The adsorption-swelling and permeability characteristics of natural and reconstituted anthracite coals

A review on pore-fractures in tectonically deformed coals

Influence of coal moisture on initial gas desorption and gas-release energy characteristics

Fines migration has posed a great challenge to gas and water production in CBM reservoirs, resulting not only in dramatic permeability reduction but also in excessive wear on equipment. The objective of this study was to investigate critical flow conditions for massive fines detachment in the dewatering phase, for the purpose of yielding an improved understanding of fines detachment mechanisms and their effective control in the field. First, fines migration experiments under saturated conditions, including effluent concentration and permeability measurements, were conducted at elevated pressure gradients on fractured coal samples with various apertures. Experimental results indicate the existence of a critical pressure gradient (CPG) for massive fines detachment. Second, a mathematical model was developed to describe single particle detachment in the fracture, accounting for the coupling effects of hydrodynamic and extended-DLVO forces. Effects of fines size and fracture aperture on fines detachment were ...

Critical Conditions for Massive Fines Detachment Induced by Single-Phase Flow in Coalbed Methane Reservoirs: Modeling and Experiments

A laboratory study of the effect of creep and fines migration on coal permeability during single-phase flow

Experimental analysis on the effect of tectonically deformed coal types on fines generation characteristics

The invention relates to an experimental method for simulating the generation and the migration of coal powder during coal-bed methane exploitation. The experimental method comprises the following steps of selecting experimental apparatuses; collecting coal rock samples to prepare artificial coal briquettes used in a simulation experiment; preparing a displacement solution for simulating fluid migrating in a coal-bed methane reservoir; preparing a propping agent filling layer for simulating a crack passage of a coal reservoir and a fracturing effect; designing an experimental scheme for simulating the generation and the migration of the coal powder during the coal-bed methane exploitation; collecting the coal powder in discharge liquid in the simulation experiment, and performing analysis on coal powder producing characteristics; and performing quantitative analysis on changes of the permeability of the coal briquettes under different experimental conditions. According to the experimental method disclosed by the invention, based on geological factors of the coal reservoir and engineering factors of coal-bed methane, horizon source, influence factors, producing characteristics and the like of the generation of the coal powder are analyzed, the physical stimulation of the geological characteristics of the coal reservoir and the physical stimulation of the draining and exploiting process of the coal-bed methane are realized, the law of the generation and the migration of the coal powder is obtained, and experimental data support is provided for the effective prevention and treatment of the production of the coal powder during the coal-bed methane exploitation.

Experimental method for simulating generation and migration of coal powder during coal-bed methane exploitation

This paper puts forward the concept of exploration types and exploration models that can be used to find coal deposits. These were developed by taking into account the complexity and spatial differences of geological and geographical conditions of China's coalfield. "Exploration types" here refers to groups of coal deposits similar in terms of the basic features of occurrence of the coal seams and the degree of difficulty of the exploration. "Exploration models" here refers to generalizations and summations of advantageous geological conditions, effective technical exploration methods, and sound exploration programs and layout schemes suitable to different exploration types on the basis of the regularity of the occurrence of coal. Depending upon several factors that determine the degree of difficulty of exploration, such as regional geological conditions, the physical geographic environment, and the level of geological prospecting work performed, exploration for coal deposits can be divided into four type...

https://journals.sagepub.com/doi/pdf/10.1260/0144-5987.29.4.495

Xiaoming Li

Papers

Experimental analysis on the effect of tectonically deformed coal types on fines generation characteristics

Experimental method for simulating generation and migration of coal powder during coal-bed methane exploitation

Types and Models of Coal-Deposit Exploration in China