hydraulic Fracturing In Coal Bed methane Reservoirs: the Prospective Methods For Enchancing Indonesia's Future Coalbed Methane Development

2018 ◽  
Author(s):  
Nur Farida
Keyword(s):  
Hydraulic Fracturing ◽  
Coalbed Methane ◽  
Coal Bed ◽  
Coal Bed Methane

scholarly journals The Influence of the Injected Water on the Underground Coalbed Methane Extraction

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1151
Author(s):  
Yanbao Liu ◽  
Zhigang Zhang ◽  
Wei Xiong ◽  
Kai Shen ◽  
Quanbin Ba
Keyword(s):  
Hydraulic Fracturing ◽  
Coalbed Methane ◽  
Gas Flow ◽  
Critical Time ◽  
Shanxi Province ◽  
Coal Bed ◽  
Hydraulic Pressure ◽  
Intrinsic Permeability ◽  
Permeability Evolution ◽  
Two Phase

The increasing demand on coal production has led to the gradually increase of mining depth and more high methane mines, which bring difficulties in terms of coalbed methane (CBM) extraction. Hydraulic fracturing is widely applied to improve the production of CBM, control mine gas, and prevent gas outbursts. It improves coal bed permeability and accelerate desorption and migration of CBM. Even though the impacts of hydraulic fracturing treatment on the coal reservoirs are rare, negative effects could not be totally ignored. To defend this defect, the presented work aims to study the influence of water filtration on coal body deformation and permeability evolution. For this purpose, a simulation based finite element method was developed to build a solid-fluid coupled two-phase flow model using commercial software (COMSOL Multiphysics 5.4). The model was verified using production data from a long strike borehole from Wangpo coal mine in Shanxi Province, China. Several simulation scenarios were designed to investigate the adverse impacts of hydraulic fracturing on gas flow behaviors. The mechanisms of both relative and intrinsic permeability evolutions were analyzed, and simulation results were presented. Results show that the intrinsic permeability of the fracture system increases in the water injection process. The impacts of water imitation were addressed that a critical time was observed beyond which water cannot go further and also a critical pressure exists above which the hydraulic pressure would impair the gas flow. Sensitivity analysis also showed that a suitable time and pressure combination could be observed to maximize gas extraction. This work provides an efficient approach to guide the coal bed methane exploitation and other unconventional gas reservoirs.

Study on the Enrichment Degree of Coalbed Methane Based on the Fuzzy Comprehensive Evaluation

2010 ◽  
Vol 34-35 ◽  
pp. 815-819
Author(s):  
Xiang Zhen Yan ◽  
Bao Hui Wang ◽  
Xiu Juan Yang
Keyword(s):  
Coalbed Methane ◽  
Reference Model ◽  
Comprehensive Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Assessment System ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Fuzzy Mathematics ◽  
Mathematics Model ◽  
Fuzzy Mathematics Model

Considering the various influencing factors of enrichment of coal bed methane, the evaluation indexes of enrichment for coal bed methane are determined. The weight values of all factors indexes are given and the fuzzy mathematics model is established on the basis of the fuzzy mathematics. As a case study, the fuzzy mathematics model is applied to the assessment of enrichment of coal bed methane. The results show that the No.5 coal seam of Shan 2 of Shanxi formation in Daning-Jixian is a better enrichment area. The evaluation result performed on the basis of the fuzzy mathematics model is in good agreement with the measured result. The example indicates that the method is credible and has high precise. The assessment system established in the paper can be regarded as a reference model in coal bed methane exploitation potential assessment.

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.

scholarly journals The pilot appraisal of acid fracturing of coalbed methane reservoir in southeast Qinshui Basin, China

2016 ◽  
Vol 20 (4) ◽  
pp. 1 ◽  
Author(s):  
Yu Yang ◽  
Chengwei Zhang ◽  
Huijun Tian ◽  
Wangang Chen ◽  
Xiadong Peng ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Coalbed Methane ◽  
Mining Area ◽  
Coal Bed ◽  
Coal Seams ◽  
Acid Sensitivity ◽  
Qinshui Basin ◽  
Acid Fracturing ◽  
Well Production ◽  
Macro Scale

The reserves of Coalbed Methane (CBM) in Qinshui Basin are quite promising, but the outputs from CBM wells are quite small even after massive hydraulic fracturing. Herein the fracture system with #3 and #15 coal seams in Qinshui basin was analyzed, and it was found that both of the macro-scale fractures and micro-scale fractures are filled with clay and carbonate minerals, which explains the low productivity of CBM wells after conventional hydraulic fracturing. Acid fracturing has long been an effective method for carbonate gas reservoir to improve the gas well production. However, there were few reports about the application of acid fracturing in coal bed methane field. Based on the mineral identification and acid sensitivity test, the feasibility of acid fracturing demonstrated that the acid does more help than damage to increase the permeability of coal seams in Qinshui basin. Onsite operations have shown that acid fracturing is applicable for the CBM wells in Jincheng Mining Area. It was also observed from the microseismic survey that when applying the acid fracturing treatment, the stimulated reservoir area depends on the acid volume pumped in the first stage, which is crucial to the success of the stimulation. Evaluación piloto de fractura ácida en depósitos de gas metano de carbón en el suroeste de la cuenca Qinshui, China  ResumenLas reservas de gas metano de carbón (CBM, del inglés Coalbed Methane) en la cuenca Qinshui son más que prometedoras, pero la producción en los pozos es muy pequeña, incluso después de fracturas hidráulicas masivas. En este trabajo se analizaron los sistemas de fractura de las vetas de carbón #3 y #15 de la cuenca Qinshui y se encontró que tanto las fracturas a macroescala como aquellas a microescala están cubiertas con arcillas y minerales carbonatos, lo que explica la baja productividad de los pozos de gas metano de carbón después de la fractura hidráulica convencional. La fractura ácida ha sido un método efectivo en los depósitos de gas carbonato para mejorar la producción en el pozo de gas. Sin embargo, existen pocos informes sobre la aplicación de la fractura ácida en el campo del gas metano de carbón. De acuerdo con la identificación mineral y las pruebas de sensibilidad ácida, la factibilidad de la fractura ácida demostró que el ácido es reparador en el incremento de la permeabilidad en las vetas de carbón de la cuenca Qinshui. Las operaciones in situ han demostrado que la fractura ácida es aplicable para los pozos de gas metano de carbón en el área minera de Jincheng. También se observó en el sondeo microsísmico que cuando se aplica un tratamiento de fractura ácida, el área del depósito estimulada depende del volumen de ácido bombeado en primera instancia, lo que es determinante en el éxito de la estimulación.

scholarly journals Prediction of Coalbed Methane Production Based on BP Neural Network

2019 ◽  
Vol 131 ◽  
pp. 01059
Author(s):  
Tianxiang Zhang ◽  
Yifang Tang ◽  
Jianjun Wu ◽  
Zixi Guo ◽  
Bing Li
Keyword(s):  
Neural Network ◽  
Bp Neural Network ◽  
Methane Production ◽  
Coalbed Methane ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Correlation Degree ◽  
Coalbed Methane Production ◽  
Exploration And Development ◽  
Production Prediction

The low average daily gas production per well and the poor economic benefit of exploration and development have become the main problems restricting the exploration and development of coalbed methane in China. Combining multiple coal seam geological parameters to predict the high-yield area of the block can not only provide guidance for the exploitation of coal-bed methane, but also bring enormous economic benefits. Aiming at the difficulty of coalbed methane dessert discrimination and production prediction, a method of coal-bed methane production prediction based on BP neural network is proposed in this paper. Starting from the average daily production of coalbed methane single well, we use the method of grey correlation degree to get the main controlling factors of coalbed methane production. For the main control factors, we use BP neural network with high fitting accuracy and get a good prediction result.

scholarly journals Research on control system of truck-mounted rig for coalbed methane

2018 ◽  
Vol 153 ◽  
pp. 04001 ◽  
Author(s):  
Hejian Wang ◽  
Dong Fan ◽  
Yinsheng Weng
Keyword(s):  
Control System ◽  
Coalbed Methane ◽  
Large Scale ◽  
Integrated Approach ◽  
Control Mode ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Hydraulic Control ◽  
Security Risk ◽  
Drilling Rig

The coal-bed methane (CBM) as a kind energy is clean and efficient, also it can become a security risk in mining process if it could not get out of the coal seam. In view of the current large-scale exploitation of coal-bed methane resources, the development of drilling rig for CBM drilling is needed. The parameters and structures were introduced in the paper. The rig uses a highly integrated approach that integrates the required functions on the chassis of the vehicle to meet the needs of rapid installation and transportation. Drilling control system uses hydraulic control and electro-hydraulic control dual control mode, can achieve short-range and remote control operations. The control system include security circuits and electric control system. Through the field trial, it is shown that the rig can meet the construction of the majority of coalbed methane drilling in the country and the performance is stable and the operation is simple.

scholarly journals Study of Cyclic Fracturing in Vertical CBM Wells

2017 ◽  
Vol 10 (1) ◽  
pp. 108-117 ◽  
Author(s):  
Ting Li ◽  
Ji-fang Wan
Keyword(s):  
Hydraulic Fracturing ◽  
Economic Benefits ◽  
Natural Fracture ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Plastic Behavior ◽  
Natural Fractures ◽  
Stimulated Reservoir Volume ◽  
Reservoir Volume ◽  
Coal Rock

Background:Coal-bed methane productivity of single well is very low, and has been the bottleneck of the coal-bed methane industry in China.Objective:Although hydraulic fracturing is the only stimulation measure to develop CBM, it cannot increase production effectively, conventional fracturing method to create opening fractures should be improved. How to make good use of natural fractures, which are plentiful in CBM reservoirs, is also an important subject for hydraulic fracturing.Method:In this paper, the plastic deformation of coal rock is analyzed by harnessing a pseudo-Maxwell creep phenomenon, which is normally present in rock. The Kelvin-Voigt model is utilized to describe pseudo-plastic behavior of coal rock to determine pressurization and decay cyclic time for cyclic fracturing design. The mechanical requirement for shearing natural fractures is also analyzed, and shearing distance between the faces of natural fracture can be calculated by Westergaard stress function. Ultimately, the cyclic fracturing method is proposed according to theories about stress alteration and shearing of natural fractures. This method includes such periods as fracturing, pumping shut-down and so on.Conclusion:A complex fracture system can be created, which consists of opened and sheared fractures, then, large SRV(stimulated reservoir volume)and flowing drainage area can be acquired. In comparison with conventional fracturing method, this new way can make full use of the characteristics of CBM reservoirs and is more suitable to CBM. This method will lead to a significant increase of CBM production, and will achieve huge economic benefits.

scholarly journals A Calculation Model of the Net Pressure for Forming Map Cracking in Coalbed with Cleats During Hydraulic Fracturing Process

2015 ◽  
Vol 8 (1) ◽  
pp. 193-197
Author(s):  
Li Yuwei ◽  
Ai Chi ◽  
Liu Yazhen
Keyword(s):  
Hydraulic Fracturing ◽  
Principal Stress ◽  
Coalbed Methane ◽  
Maximum Principal Stress ◽  
Calculation Model ◽  
Coal Bed ◽  
Minimum Principal Stress ◽  
Fracturing Process ◽  
The Face ◽  
Net Pressure

An important prerequisite for achieving efficient exploitation of coalbed methane wells is through forming map cracking by hydraulic fracturing. In order to analyze the mechanical mechanism for forming map cracking of the coal bed with cleats, the mechanical conditions for forming map cracking during hydraulic fracturing process of coal bed was proposed using extensional faulting in elastic mechanics and the shear damage criterion, and the minimum net pressure calculation model for forming map cracking was established when the butt cleat and face cleat in coal opened at the same time. It can be concluded through using the calculation model that the net pressure value that needed for forming map cracking first decreased and then increased with the increasing of the angle between the face cleat and the direction of horizontal minimum principal stress. The cleats and fissures developed along the horizontal maximum principal stress were easy to open and extend under the effect of hydraulic fracturing. The variation of the internal friction coefficient variation of the face cleat had little effect on the minimum net pressure that was needed for forming map fracturing after the angle between the direction of face cleat and horizontal minimum principal stress is determined.

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