Experimental investigation on the effect of organic solvents on gas development of coalbed methane reservoir

Mao, Gangtao; Li, Zhiping; Lai, Fengpeng; Wei, Hexin

doi:10.1016/j.fuel.2020.119497

Cited by 6 publications

(3 citation statements)

References 38 publications

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“…The loose property of cores limits the higher centrifugal speed; it is known from the previous experiments in the same block that destructive cracks appeared in the sample above a speed of 2000 rpm. 22,23 Therefore, the maximum centrifugal speed designed in this experiment was 2000 rpm. The centrifugal process lasted 40 min under each speed, and then the core was weighed.…”

Section: Methodsmentioning

confidence: 99%

Effect of Nanoparticle Adsorption on the Pore Structure of a Coalbed Methane Reservoir: A Laboratory Experimental Study

Wang

Mao

et al. 2022

ACS Omega

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Coalbed methane (CBM) is an important unconventional energy resource, and its micropore structure has a vital impact on its exploitation. Based on the nuclear magnetic resonance (NMR) experiment, the low-temperature liquid nitrogen adsorption experiment, and the contact angle experiment, in this paper, we investigated the influence of nanofluids on the micropore structure of a CBM reservoir from many aspects. The influence of different adsorption mechanisms of TiO2 nanoparticles on the surface wettability of rock samples was analyzed. The influence of nanoparticle adsorption on the drainage and distribution of liquid in the rock sample was discussed in depth. In addition, the effects of nanofluid treatment on the micropore structure were investigated by comparing the data of low-temperature liquid nitrogen adsorption experiments, including the pore diameter, pore volume, and specific surface area (SSA). The experimental results show that the treatment of nanofluids helps to open the micropores and greatly increases the SSA, pore diameter, and pore volume of the sample. The maximum increase percentages of SSA, pore volume, and pore diameter are 228.12, 80.65, and 18.89%, respectively. It is found that the adsorption of particles is conducive to enhancing the water wettability of the pore throat surface and reducing the damage to water locks.

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Section: Methodsmentioning

confidence: 99%

Effect of Nanoparticle Adsorption on the Pore Structure of a Coalbed Methane Reservoir: A Laboratory Experimental Study

Wang

Mao

et al. 2022

ACS Omega

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“…Hao et al 25 treated lignite, long flame coal, fat coal, meager coal, and anthracite with tetrahydrofuran and found that the extraction rate of each coal sample increased rapidly and then slowly with the increase of extraction time, also showing an increasing and then decreasing trend with the increase of coalification degree. Mao et al 26 investigated the impact of organic solvents on coalbed methane mining through experiments and found that 2-ethoxyethanol and ethanol could effectively increase the specific surface area, pore size, and pore opening of coal samples.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Pore-Fracture Variations in Coal Affected by Carbon Disulfide

Zheng,

Li,

et al. 2023

ACS Omega

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Solvent treatment is an effective technique to stimulate pore and fracture growth in low-permeability coal seams and improve the efficiency of methane extraction. Adopting the nuclear magnetic resonance test, liquid nitrogen adsorption analysis, ultrasonic test, and CT scanning, pore variation and fracture development in lignite, bituminous coal, and anthracite after carbon disulfide treatment were analyzed. Full-scale pore size distribution characteristics were obtained. The Frenkel–Halsey–Hill model was adopted to analyze pore fractal properties. Experiment results show that carbon disulfide could increase coal porosity. Lignite showed the best pore alteration effect, with a porosity increase of 34.10%, followed by bituminous coal with a porosity increase of 14.55%, while anthracite had a slightly weaker change with only 0.91% porosity growth. The pore diameter distribution range of treated coal expanded from 0–450 to 0–1000 μm. The average pore diameter rose from 316 to 483 μm, with better connectivity between pores. After treatment, the proportions of micropore specific surface areas (SSA) in three coal samples decreased but the ratios of small pore and medium pore SSA increased. Fractal dimension D 1 of lignite and bituminous coal decreased by 5.669 and 0.054%, while D 1 of anthracite increased by 22.407%. D 2 reduced by 0.599, 3.143, and 1.262%, respectively. Raw coal had the maximum porosity near both ends of the CT section. Porosity of lignite was the largest at the ends after treatment. Surface porosity inside coal samples also rose from about 0.1 in raw coal to approximately 0.4 after treatment. Ultrasonic velocity in lignite decreased by 50.16% due to solvent treatment. Increases in ultrasonic attenuation coefficient α and ultrasonic attenuation ratio β indicate good fracture development. Furthermore, development degrees of lignite and bituminous coal are higher than that of anthracite. Results of the above methods verify with each other, indicating the effectiveness of carbon disulfide treatment in improving pore and fracture structures. The outcomes of this research could offer a theoretical basis for chemical permeability-enhancement technology.

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“…Therefore, it is important to develop a new experimental method to calculate the fractal dimension and phase relative permeability curve. Nuclear magnetic resonance (NMR) is currently a fast and convenient method to study the pore-throat structure, which can reflect the full pores of fluid flow and is widely used in the study of the pore-throat structure and the fractal characteristics of current tight reservoirs. − However, at present, there is little research on the calculation method of relative permeability using nuclear magnetic data. Moreover, because the saturation and centrifugation of NMR often use higher saturation and displacement pressure than that of the relative permeability experiment, inaccurate relative permeability results are often obtained, further limiting the usage of the calculation methods.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Prediction Method of Liquid Retention Based on Nuclear Magnetic Resonance

Mao

Lai

et al. 2022

Energy Fuels

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For tight gas reservoirs such as water-sensitive and low permeability, the incoming fluids are the most important external factors that damage oil and gas reservoirs. The liquid phase retention has become an important influence factor of production capacity. At present, the water blockage damage degree is often used to evaluate the liquid phase retention degree. Therefore, based on the study of fractal dimension by a NMR (nuclear magnetic resonance) experiment, using the existing formula of the fractal calculation of the relative permeability curve, this paper improves the relevant formula for calculating water blockage damage for NMR and studies the relative permeability curve and water blockage damage rate of tight gas reservoirs. According to the calculation results, the fractal dimension of the samples is 2.3551− 2.7417, and the average value is 2.492. This shows that the micro-pore structure of core samples is relatively complex with medium heterogeneity. Through the analysis of the relative permeability curve, it can be deduced that the rocks in this block have strong hydrophilicity, and the gas−water two-phase seepages in this block strongly interfere with each other. Besides, the comparative analysis shows that the method of calculating water blockage damage rate is accurate and the average error is only 4.59%. The average damage degree of water blockage in this block is moderate water blockage damage. The results of the parametric analysis also demonstrate that irreducible water saturation and pore-throat structure relationship are the key factors governing the water blockage degree, which determines the damage degree of foreign liquid retention to reservoirs.

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Experimental investigation on the effect of organic solvents on gas development of coalbed methane reservoir

Cited by 6 publications

References 38 publications

Effect of Nanoparticle Adsorption on the Pore Structure of a Coalbed Methane Reservoir: A Laboratory Experimental Study

Effect of Nanoparticle Adsorption on the Pore Structure of a Coalbed Methane Reservoir: A Laboratory Experimental Study

Experimental Investigation on Pore-Fracture Variations in Coal Affected by Carbon Disulfide

Quantitative Prediction Method of Liquid Retention Based on Nuclear Magnetic Resonance

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