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

2014 ◽  
Vol 1030-1032 ◽  
pp. 1388-1393 ◽  
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.

Study on Well Logging Technology with Methods of Evaluating Gas Content of Coal-Bed Methane Reservoir

2014 ◽  
Vol 1003 ◽  
pp. 183-187
Author(s):  
Huai Jie Yang ◽  
He Ping Pan
Keyword(s):  
Statistical Analysis ◽  
Coal Seam ◽  
Well Logging ◽  
Langmuir Equation ◽  
Gas Content ◽  
Coal Bed ◽  
High Yield ◽  
Coal Bed Methane ◽  
Analysis Method ◽  
Statistical Analysis Method

In this study, the well logging response of CBM reservoir have been analyzed, and discussing the factors that affect the gas content of coal seam. The well logging technology has been employed in connection with log data and gas content. Take one oilfield’s well logging data for example, statistical analysis method and Langmuir equation method are selected to calculate the gas content of one coal seam, the two calculated results are basically the same, the highest value are about 26 cm3/g, is a high-yield coal seam.

Coal Particles Cleanout Technology in Coal Bed Methane Wells

2012 ◽  
Vol 229-231 ◽  
pp. 2470-2473 ◽  
Author(s):  
Bing Liu ◽  
Yao Guang Qi ◽  
Chao Wang ◽  
Chun Cheng Xu ◽  
Fen Na Zhang ◽  
...  
Keyword(s):  
High Efficiency ◽  
New Technology ◽  
Gas Production ◽  
Coal Bed ◽  
Working Fluid ◽  
Coal Bed Methane ◽  
Skin Damage ◽  
Technology System ◽  
Coal Particles ◽  
Continuous Vacuum

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.

Research on Result Prediction of Coal-Bed Gas Wells Fracturing by Using Expert System

2013 ◽  
Vol 734-737 ◽  
pp. 1445-1449
Author(s):  
Chi Ai ◽  
Chao Yang Hu ◽  
Yu Wei Li ◽  
Feng Jiao Wang
Keyword(s):  
Expert System ◽  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Gas Content ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Main Method ◽  
Number Of Factors ◽  
Coal Seam Thickness ◽  
Expert Database

Hydraulic fracturing is the main method to increase the output of coal-bed methane wells, however, the hydraulic fracturing result of coal-bed methane well is usually affected by large number of factors such as the conditions of coal-bed, the conditions of coal-bed methane well, fracturing operation parameters and so on. As a result, the fracturing operation result is difficult to predict. This paper assumed coal seam thickness, the depth of coal seam, coal seam gas content and other six main factors which affect hydraulic fracturing results by analysis various factors. Membership function of the expert system was established to divide the level of each factor. The established method which applies the expert system to predict the hydraulic fracturing results of coal-bed methane wells was based on expert database. Using the established expert system to calculate 200 groups of test data and the prediction error rate is only 3.5%. The prediction results are accurate and reliable, and can provide guidance for coal-bed methane wells fracturing optimization.

The Research and Application of Coal-Bed Methane Surface Gathering Process

2014 ◽  
Vol 962-965 ◽  
pp. 899-902
Author(s):  
Mei Ting Jiang ◽  
Yi Shan Lou ◽  
Hao Yuan Wei
Keyword(s):  
Capital Investment ◽  
Produced Water ◽  
Plant Size ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Processing Plant ◽  
Gas Field ◽  
Central Processing ◽  
Single Well ◽  
Large Water

China is rich in coal-bed methane (CMB) resources, and has a vast exploitable volume, but the surface gathering system is not perfect. In order to solve the problems of high degree of difficulty in surface gathering system design and lower economic efficiency caused by the characteristics of CBM gas field geographically remote, more wells, large water production in single well and gas containing pulverized coal etc, we studied the select method of the piping material of CBM, process and the treatment technologies of produced water in F block of the southern Qinshui Basin. Finally, the first phase production can reach 6 × 108m3/a and the central processing plant size is 10 × 108m3/a in the F block. The application of this study not only reduced the capital investment but also met the requirement of good environmental protection. This gathering process design can be applied to other development and construction of CBM gas fields.

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

2016 ◽  
Vol 9 (1) ◽  
pp. 289-298 ◽  
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.

Impact of in-seam drilling performance on coal seam gas production and remaining gas distribution

2019 ◽  
Vol 59 (1) ◽  
pp. 328
Author(s):  
Fengde Zhou ◽  
Glen Fernandes ◽  
Joao Luft ◽  
Kai Ma ◽  
Mahmoud Oraby ◽  
...  
Keyword(s):  
Coal Seam ◽  
Gas Production ◽  
Gas Content ◽  
Gas Distribution ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Gas Saturation ◽  
Drilling Performance ◽  
Permeability Anisotropy ◽  
The Impact

Drilling horizontal wells in low permeability coal seams is a key technology to increase the drainage area of a well, and hence, decrease costs. It’s unavoidable that some parts of the horizontal section will be drilled outside the targeted coal seam due to unforeseen subsurface conditions, such as sub-seismic faulting, seam rolls, basic geosteering tools, drilling practices and limited experiences. Therefore, understanding the impact of horizontal in-seam drilling performance on coal seam gas (CSG) production and remaining gas distribution is an important consideration in drilling and field development plans. This study presents a new workflow to investigate the impact of horizontal in-seam performance on CSG production and gas distribution for coal seams with different porosity, permeability, permeability anisotropy, initial gas content (GC), initial gas saturation and the ratio of in-coal length to in-seam length (RIIL). First, a box model with an area of 2 km × 0.3 km × 6 m was used for conceptual simulations. Reduction indexes of the cumulative gas production at the end of 10 years of simulations were compared. Then, a current Chevron well consisting of a vertical well and two lateral wells, was selected as a case study in which the impact of outside coal drilling on history matching and remaining gas distribution were analysed. Results show that the RIIL plays an increasing role for cases with decreasing permeability or initial gas saturation, while it plays a very similar role for cases with varied porosity, permeability anisotropy and GC. The size and location of outside coal drilling will affect the CSG production and remaining gas distribution.

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