A prediction model for desorption area propagation of coalbed methane wells with hydraulic fracturing

Sun, Zheng; Shi, Juntai; Wu, Keliu; Liu, Wenyuan; Wang, Suran; Li, Xiangfang

doi:10.1016/j.petrol.2018.12.047

Cited by 37 publications

(24 citation statements)

References 44 publications

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“…permeability reduction should be relatively less and the drainage area should be enough longer. From this point, some prediction models for drainage area and desorption area expansion have been proposed (Sun et al, 2017(Sun et al, , 2019aWan et al, 2016). These models require to combine with the actual water production to get the drainage radius, which is not suitable for the dewatering rate optimization in the early single-phase water.…”

Section: Introductionmentioning

confidence: 99%

Novel method for optimizing the dewatering rate of a coal-bed methane well

Wu²,

Li³

et al. 2020

Energy Exploration & Exploitation

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The reasonable dewatering rate in the single-phase water flow plays an essential role in pressure propagation and coal-bed methane production. However, current fluid velocity sensitivity experiments cannot provide an optimum dewatering rate for field coal-bed methane production. This study proposes a new method to optimize the dewatering rate for coal-bed methane wells by assuming the investigation distance reaches the well boundary when the bottom hole pressure declines to the critical desorption pressure. The effect of the stress sensitivity and fluid velocity sensitivity on pressure propagation was first simulated with COMSOL Multiphysics software. The results showed that the expansion area considering the stress sensitivity is shorter than that neglecting the stress sensitivity when the bottom hole pressure reached to the critical desorption pressure at 200 days. The expansion area with high dewatering rate will be shorter about 35 m than that with low dewatering rate at 200 days. The relationship between the maximum investigation distance and required time was established to optimize the dewatering rate by combining the pressure profile considering the influence of stress sensitivity with material balance equation. The new model indicates that the initial permeability, porosity, and cleat compressibility have an important effect on investigation distance. The simulation of these parameters’ sensitivity suggests that the bigger the ratio of initial permeability and porosity, the longer the investigation distance is, and the smaller the cleat compressibility is, the longer the expansion area is. According to this model, we need to take more than 600 days at 0.58 m/d constant dewatering rate to reach the maximum investigation distance of 0.67 mD initial permeability. This work can be conducive to choose reasonable dewatering rate in single-phase water flow for coal-bed methane well production.

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Section: Introductionmentioning

confidence: 99%

Novel method for optimizing the dewatering rate of a coal-bed methane well

Wu²,

Li³

et al. 2020

Energy Exploration & Exploitation

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“…As reported by United States Energy Information Administration (EIA) in 2019, unconventional reservoirs can cost-effectively produce gas only by using a special stimulation technique, like hydraulic fracturing, or other special recovery process and technology [29]. Hydraulic fracturing not only produces hydraulic fractures with high conductivity, but also creates complex induced fracture around hydraulic fractures [28,30,31]. The area containing the complex induced fracture is called the effectively stimulated reservoir volume (ESRV), which greatly enhances the reservoir permeability and has a decisive influence on production well production [32,33].…”

Section: Introductionmentioning

confidence: 99%

Water-Gas Two-Phase Flow Behavior of Multi-Fractured Horizontal Wells in Shale Gas Reservoirs

Sheng

2019

Processes

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Hydraulic fracturing is a necessary method to develop shale gas reservoirs effectively and economically. However, the flow behavior in multi-porosity fractured reservoirs is difficult to characterize by conventional methods. In this paper, combined with apparent porosity/permeability model of organic matter, inorganic matter and induced fractures, considering the water film in unstimulated reservoir volume (USRV) region water and bulk water in effectively stimulated reservoir volume (ESRV) region, a multi-media water-gas two-phase flow model was established. The finite difference is used to solve the model and the water-gas two-phase flow behavior of multi-fractured horizontal wells is obtained. Mass transfer between different-scale media, the effects of pore pressure on reservoirs and fluid properties at different production stages were considered in this model. The influence of the dynamic reservoir physical parameters on flow behavior and gas production in multi-fractured horizontal wells is studied. The results show that the properties of the total organic content (TOC) and the inherent porosity of the organic matter affect gas production after 40 days. With the gradual increase of production time, the gas production rate decreases rapidly compared with the water production rate, and the gas saturation in the inorganic matter of the ESRV region gradually decreases. The ignorance of stress sensitivity would cause the gas production increase, and the ignorance of organic matter shrinkage decrease the gas production gradually. The water film mainly affects gas production after 100 days, while the bulk water has a greater impact on gas production throughout the whole period. The research provides a new method to accurately describe the two-phase fluid flow behavior in different scale media of fractured shale gas reservoirs.

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Section: Introductionmentioning

confidence: 99%

“…Hydraulic fracturing, as one of the most effective stimulation methods to exploit oil and gas, plays an important role in the development of different type of reservoirs worldwide. [1][2][3][4][5][6][7][8][9][10][11] As an emerging technology for the enhancement of well production, pulsating fracturing shows its outstanding potential in the exploitation of unconventional oil and gas reservoirs (such as coal bed methane formation). Compared with the traditional hydraulic fracturing technology, pulsating fracturing is more likely to cause damage to the rock, reduce the strength of the rock, [12][13][14] and facilitate the propagation of fractures in the rock.…”

Section: Introductionmentioning

confidence: 99%

Rock damage evolution model of pulsating fracturing based on energy evolution theory

Zhao²,

Tang

et al. 2019

Energy Science & Engineering

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Pulsating fracturing, as a new technology for unconventional oil and gas exploration, enables to enhance stimulated reservoir volume (SRV) effectively, which further helps to improve well performance. It is of great importance for the evaluation of fracturing performance and optimization of fracturing parameters by accurately calculating variables from formation impairment during pulsating fracturing treatment. Based on the principle of conservation of energy, a novel theoretical model describing the evolution of rock damage was proposed by analyzing energy evolutionary characteristics from the hysteresis loop of rock stress‐strain curve while the treatment. This model was in a good agreement with experimental data. In this paper, our study indicates that the rock damage is caused by the accumulation of damage in each cyclic loading and unloading process during pulsating fracturing. Moreover, the cumulative rock damage would increase with the increment of the number of cyclic loading and unloading. Conversely, the rock strength is negatively correlated with cyclic number. The cumulative damage variable approximates to one as the rock breaks. Additionally, the frequency and the stress level of pulsating fracturing have an obvious impact on the evolution of rock damage. The optimization of these parameters can help to accelerate the rock damage and reduce the corresponding rock strength. The speed of rock damage can be accelerated with the enhancement of the stress level at the later period of the step loading, which facilitates the increment of cumulative damage variable. Our new model provides a guideline for predicting the initial rock damage during pulsating treatment.

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A prediction model for desorption area propagation of coalbed methane wells with hydraulic fracturing

Cited by 37 publications

References 44 publications

Novel method for optimizing the dewatering rate of a coal-bed methane well

Novel method for optimizing the dewatering rate of a coal-bed methane well

Water-Gas Two-Phase Flow Behavior of Multi-Fractured Horizontal Wells in Shale Gas Reservoirs

Rock damage evolution model of pulsating fracturing based on energy evolution theory

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