A discussion on CBM development strategies in China: A case study of PetroChina Coalbed Methane Co., Ltd.

Wen, Shengjun; Zhou, Ke; Lu, Qian

doi:10.1016/j.ngib.2019.10.001

Cited by 26 publications

(21 citation statements)

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“…The coalbed methane (CBM) resource in China was estimated to be more than 36 × 10 12 m 3 in coal seam with a buried depth less than 2000 m, which is the world’s third largest resource. − Although the CBM development in China has lasted for more than 30 years, it still faces huge challenges in improving the productivity of the CBM well. − Low permeability is one of the most important factors that led to poor gas production in coal seams . As a result, a number of stimulation methods have been developed for low-permeability coal seams.…”

Section: Introductionmentioning

confidence: 99%

Permeability Enhancement via Acetic Acid (CH₃COOH) Acidizing in Coals Containing Fracture-Filling Calcite

Chen

Wang

2021

Energy Fuels

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Calcite is one of the most common fracture-filling minerals in low-permeability coal seams and can be dissolved easily by acid. Although much attention has been paid recently to coal seam acidizing, only few studies have focused on the permeability evolution during the injection of organic acid, which has a very different reaction rate and dissolution structure morphology from those of conventional strong acids (e.g., HCl and HF). In this study, 0.25−1.0 mol/L acetic acid (CH 3 COOH) was injected into the coal plug samples from the Fuxin Basin in China, whose fractures were completely infilled by calcite. The evolution of plug permeability during CH 3 COOH flooding was monitored. Before and after flooding experiments, the coal plugs were characterized using micro-computed tomography imaging, scanning electron microscopy, and nuclear magnetic resonance. The results showed that fracture-filling calcite exhibits high reactivity after exposure to CH 3 COOH at the temperatures of 20, 30, and 40 °C, and the macro-/microscale highly conductive flow channels between the inlet and the outlet of coal plugs can be formed in several hours. Thus, a significant permeability improvement from less than 0.02 mD to over 27 mD was observed during CH 3 COOH flooding. These increases ranging from 131 to 2720 times of the initial permeability are mainly due to the presence of fracture-filling calcite with high connectivity and the absence of fine migration, clay swelling, and secondary Fe-rich precipitation in the CH 3 COOH environment. The results also suggested that the minimum volume of CH 3 COOH required for a highly conductive flow channel breakthrough can be less than 1.0 PV. This investigation demonstrated the potential of deep matrix-acidizing treatment using CH 3 COOH for improving the permeability and enhanced coalbed methane recovery in coal seams containing fracture-filling calcite.

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Section: Introductionmentioning

confidence: 99%

Permeability Enhancement via Acetic Acid (CH₃COOH) Acidizing in Coals Containing Fracture-Filling Calcite

Chen

Wang

2021

Energy Fuels

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“…China's CBG reserve amounts to 36.8 trillion cubic meters, ranking the third in the world. According to the China's "13th Five-Year Plan" from 2015 to 2020 (Wen et al, 2019), in the year of 2020, the proven geological reserve of newly-increased CBG reserve is 420 billion cubic meters, the extracted CBG volume will reach 24 billion cubic meters, of which 14 billion cubic meters will be extracted from coal mines, and the utilization rate of CBG will increase to 50%. Figure 1 shows the CBG extraction volume and utilization rate in China during 2012 and 2018.…”

Section: Introductionmentioning

confidence: 99%

A “full spectrum-domain-time” coalbed gas utilization model and its application in mining area

Linghu

Chen

Jiang

2021

Energy Exploration & Exploitation

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Coalbed gas (CBG) has been widely used as an important energy source. However, its utilization and allocation system is imperfect in mining areas. During the utilization process, a large amount of CBG is discharged into the air, causing environmental pollution. In this study, we proposed a “full spectrum-domain-time” CBG utilization model. In this model, by combining high methane concentration gas power generation, low methane concentration gas purification, and ultra-low methane concentration gas thermal storage and oxidation utilization, we were able to utilize CBG with full-spectrum of methane concentrations. In addition, by establishing CBG transportation and storage system in mining area, we were able to realize CBG supply in the entire network domain. Furthermore, based on the time series prediction algorithm, the CBG demand of different mining areas is predicted and regulatorily met by real time allocation. Through these three steps, an efficient “full spectrum-domain-time” CBG utilization system was formed and practically applied in Yangquan mining area. The application results showed that under the comprehensive control of “full spectrum-domain-time” CBG utilization model, CBG with methane concentration ≥0.2% could be used in the mining area and its utilization rate increased year by year, reaching the highest of 77.15%. Overall, our study provided a reference for the efficient CBG utilization in the mining area.

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“…As an unconventional energy source, CBM has the advantages of being clean, as well as environmentally friendly, and thus, it is widely exploited and used. PetroChina Coalbed Methane Co., Ltd has been continuously intensifying the exploration and development of CBM, and it has achieved an increase in the average annual production and sales equivalent to 50 × 10 4 t of oil, with an annual output of 200 × 10 4 t upon the completion of the construction of an unconventional gas field in 2019 (Wen et al., 2019).…”

Section: Introductionmentioning

confidence: 99%

Experimental study on the influence of coal powders on the performance of water-based polymer drilling fluid

Zhang

Lyu

et al. 2020

Energy Exploration & Exploitation

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Coal powders, as cuttings, invade the drilling fluid along a coal seam during coalbed methane development, thereby changing the properties of the drilling fluid. Therefore, this work aims to investigate the influence of coal powders on drilling fluid performance. The powders of lignite, anthracite, and contrasting shale were added to a water-based polymer drilling fluid. Then, the rheology, filtration, lubricity, and adhesiveness were measured, and the natural degradation, as well as the wettability were further evaluated. The results show that some parameters of the drilling fluid, including viscosity, lubrication coefficient, adhesion coefficient, contact angle, and surface tension, increase after adding coal powders, while other parameters, such as filtration loss and natural degradation, decrease. Compared with lignite and shale, anthracite powders, with the lowest mineral content, exhibit the smallest change in the rheological property, lubricity, adhesion, and natural degradation of the drilling fluid. Moreover, the content and size of the coal powders generally have opposing effects on the drilling fluid. When the coal powder content reaches 3 wt.%, the surface tension and contact angle of the drilling fluid show more evident changes than other parameters. Based on the analysis of the stress intensity factor, the drilling fluid with coal powders exceeding 100 mesh can reduce the capillary force in microfractures, and in combination with other factors (such as reduced filtration loss and sealing and supporting of the microfractures), improves wellbore stability. Therefore, coal powders with suitable particle sizes and concentration levels are expected to become a new drilling fluid material to protect coal field reservoirs.

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A discussion on CBM development strategies in China: A case study of PetroChina Coalbed Methane Co., Ltd.

Cited by 26 publications

References 1 publication

Permeability Enhancement via Acetic Acid (CH₃COOH) Acidizing in Coals Containing Fracture-Filling Calcite

Permeability Enhancement via Acetic Acid (CH₃COOH) Acidizing in Coals Containing Fracture-Filling Calcite

A “full spectrum-domain-time” coalbed gas utilization model and its application in mining area

Experimental study on the influence of coal powders on the performance of water-based polymer drilling fluid

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A discussion on CBM development strategies in China: A case study of PetroChina Coalbed Methane Co., Ltd.

Cited by 26 publications

References 1 publication

Permeability Enhancement via Acetic Acid (CH3COOH) Acidizing in Coals Containing Fracture-Filling Calcite

Permeability Enhancement via Acetic Acid (CH3COOH) Acidizing in Coals Containing Fracture-Filling Calcite

A “full spectrum-domain-time” coalbed gas utilization model and its application in mining area

Experimental study on the influence of coal powders on the performance of water-based polymer drilling fluid

Contact Info

Product

Resources

About

Permeability Enhancement via Acetic Acid (CH₃COOH) Acidizing in Coals Containing Fracture-Filling Calcite

Permeability Enhancement via Acetic Acid (CH₃COOH) Acidizing in Coals Containing Fracture-Filling Calcite