Enhancing Gas Production in Coal Bed Methane Formations with Zeta Potential Altering System

Coal particles cleanout which is regarded as the key technology in the operation of coal bed methane (CBM) wells, play an important part in making steady production. In oil wells, Sand cleanout is operated by circulating a liquid or a multiphase fluid into the wellbore to bring sand particles to the surface. Although the sand cleanout operations have been applied successfully in most wells with high efficiency and negligible leakage, it would leak working fluid into coal bed formation, destroy the structure of coal bed and jam the formed channel of gas production. In this paper, a new continuous vacuum cleanout technology has been developed to effectively remove coal particles in CBM wells by employing a jet pump. The Concentric Tubing String (CTS) which is assembled by 3.5 inch tubing and 1.5 inch tubing is also introduced in, because there is no CCT technology in China at the moment. Detailed structure and principle of the coal particles cleanout technology system are described, while a theoretical model is formulated to optimally design the system based on the coal particles settling experimental data and jet pumping theory. It has been shown from field applications that the coal particles cleanout technology makes significant improvements in achieving high efficiency and preventing leakage in CBM wells. Moreover, the new technology reduces the skin damage and increase the production compared to non-vacuum CBM wells.

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Analysis on Production of Coal Bed Methane Considering the Change in Permeability of Coal Rock

The Open Petroleum Engineering Journal ◽

10.2174/1874834101609010289 ◽

2016 ◽

Vol 9 (1) ◽

pp. 289-298 ◽

Cited By ~ 2

Author(s):

Zhu Likai ◽

Ji Youjun ◽

Yang Tianhong ◽

Li Xiaoyu

Keyword(s):

Coal Mine ◽

Confining Pressure ◽

Gas Production ◽

Coal Bed ◽

Coal Bed Methane ◽

Methane Extraction ◽

Coal Rock ◽

Cbm Production ◽

Stable Yield ◽

Set Up

Based on the mechanism of migration of the coal bed methane (CBM), and taking into account the deformation of the coal rock during the process of CBM production was also taken into account, a coupled mathematical model considering the interaction of solid and fluid for methane extraction was built. The coal gas extraction of JINcheng coal mine was taken as an example, some typical coal sample was chosen to test the permeability under different confining pressure. The curve for permeability of coal rock versus effective stress under different confining pressure was obtained, a numerical model considering the variation of permeability for methane extraction was set up. The influence of deformation of coal rock on the gas production was simulated and analyzed. The simulation results indicate that the productivity curve considering deformation of rock is closer to the actual production data, at the initial stage of production, the gas rate is less than the case without considering deformation of rock, but the time of stable yield will last longer, and this matches the actual methane extraction, therefore, we recommend that the deformation of coal seam should be considered during the prediction of methane production for JINcheng coal mine.

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Peak Gas Production Analysis and Influencing Factors Study of Coal Bed Methane Well

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1030-1032.1388 ◽

2014 ◽

Vol 1030-1032 ◽

pp. 1388-1393 ◽

Cited By ~ 2

Author(s):

Wei Ding ◽

Hua Chao Sun ◽

Zhao Hui Xia ◽

Yun Peng Hu ◽

Qiang Fu Kong ◽

...

Keyword(s):

Influencing Factors ◽

Gas Production ◽

Gas Content ◽

Coal Bed ◽

Coal Bed Methane ◽

Gas Field ◽

Gas Saturation ◽

Desorption Time ◽

Study Results ◽

Cleat Porosity

The value of peak gas production and the time when it reaches are two important marks for coal bed methane (CBM) well’s gas production curve. This paper takes M CBM gas field of A country’s B basin as actual production instance. Firstly, based on the CBM producing mechanism, the existence reason of peak gas rate is analyzed; secondly, the influencing factors of the value of peak gas production and the time when it reaches is studied by numerical simulation method. And sensitivity order of the influencing factors is obtained. The study results indicate that: the value of peak gas production has positive correlation with properties: permeability, gas content, coal bed net pay and gas saturation; while negative correlation with desorption time and cleat porosity. And the strong to weak intensity of sensitivity is permeability, gas content, desorption time, net coal bed pay, cleat porosity, gas saturation. The time when peak gas production reaches is markedly influenced by the value desorption time and cleat porosity, the smaller of the two parameters, the shorter of the time when peak gas production reaches.

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New Technique to Accelerate Gas Production on CBM Through Use of Sacrifice Well

Modern Applied Science ◽

10.5539/mas.v12n1p86 ◽

2017 ◽

Vol 12 (1) ◽

pp. 86

Author(s):

Leksono Mucharam ◽

Silvya Rahmawati ◽

Rafael Purba

Keyword(s):

Gas Production ◽

New Technique ◽

Coal Bed ◽

Coal Bed Methane ◽

Great Promise ◽

New Techniques ◽

Technical Problems ◽

Methane Gas ◽

The World ◽

Unconventional Resource

Coal Bed Methane (CBM) is an unconventional resource that shows great promise, particularly in Indonesia, whose CBM reservoir is relatively thick. Gas reserves of CBM are estimated at 450 TSCF in Indonesia, which makes it, the 6th largest CBM-containing country in the world. However, regulatory and technical limitations slow the progression of the exploitation of this resource. One of the fundamental technical problems is related to the length of gas production due to the duration of the dewatering time. Many studies have been developed related to the production of CBM, and this paper discusses several characteristics, patterns and techniques regarding the production of methane gas from coal through the use of a sacrifice well. Several scenarios are analysed with the use of a simulator. The results show that the production of a thick CBM reservoir, with some sensitivity patterns of production through the use of a sacrifice well, have an influence on the production of gas and water for the exploitation of CBM resources. In other words, the use of new techniques that are discussed in this paper have an impact on reducing the dewatering time and are effectively implemented in Indonesia, which has thick CBM formations.

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A Study on the Mechanical Mechanism of Injection Heat to Increase Production of Gas in Low-Permeability Coal Seam

Energies ◽

10.3390/en12122332 ◽

2019 ◽

Vol 12 (12) ◽

pp. 2332 ◽

Cited By ~ 1

Author(s):

Hongmei Cheng ◽

Ning Zhang ◽

Yugui Yang ◽

Weihong Peng ◽

Heng Chen

Keyword(s):

Rock Mass ◽

Coal Seam ◽

Production Efficiency ◽

Gas Diffusion ◽

Gas Production ◽

Gas Pressure ◽

Coal Bed ◽

Coal Bed Methane ◽

Field Coupling ◽

Gas Seepage

This paper puts forward a new mathematical model, which is a coal damage-heat-fluid-solid multi-field coupling theory, in order to reveal the mechanical mechanism of the increase of coal-bed methane recovery through thermal stimulation, and to evaluate its effect. The strain field is introduced to define the damage of coal by considering of the effects of temperature, gas pressure, and mining stress of the coal seam. It is used to quantitatively describe the degree of coal rupture and damage. Additionally, the elastic and damage constitutive equation of coal and rock mass, the governing equation of the temperature field, and the coupling equation of gas diffusion and seepage are established. Based on these equations, the finite element source program is redeveloped by using the FORTRAN language, and a multi-field coupling analysis program is compiled. This program takes the temperature, the gas seepage, and the damage and deformation of coal and rock mass into consideration. The effect of heat injection temperature on gas production efficiency, gas pressure distribution, and effective extraction radius during coal-bed methane mining process is analyzed. The results show that the injection of heat can significantly improve the desorption and diffusion of gas, as well as the gas production rate and the production efficiency of coal-bed methane.

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Efficiency Research of the Equipment of Water Pumping and Gas Production for CBM Well

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.479-481.720 ◽

2012 ◽

Vol 479-481 ◽

pp. 720-724

Author(s):

Tao Ren ◽

Yi Xiao Guo ◽

Wen Tao Qu ◽

Yan Ping Sun

Keyword(s):

Compression Ratio ◽

Gas Production ◽

Influential Factor ◽

Coal Bed ◽

Coal Bed Methane ◽

Pump Efficiency ◽

Water Pumping ◽

Reducing Gas ◽

Improvement Measures ◽

Low Efficiency

According to the characteristics of the low efficiency of drainage equipment for coal bed methane wells, we analyzed and calculated the coefficient of fullness, plunger stroke loss, leakage and volume factor, which affect pump efficiency. After analyzing the displacement loss caused by various factors, we obtained coefficient of fullness of the most influential factor on the pump efficiency. By analyzing the change relationship among the coefficient of fullness and clearance space, gas fluid ratio, compression ratio and pumping speed, we found shrinking clearance space and reducing gas fluid ratio, compression ratio and pumping speed can increase coefficient of fullness, and we presented several improvement measures to improve pump efficiency. These measures will enable coal bed methane wells production more stable and efficient.

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