Modeling of 1D Anomalous Diffusion in Fractured Nanoporous Media

Albinali, Ali; Holy, Ralf; Sarak, Hulya; Özkan, Erdal

doi:10.2516/ogst/2016008

Cited by 22 publications

(13 citation statements)

References 28 publications

(29 reference statements)

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“…If we consider the fractal of the fracture in time, it will pose a greater challenge to the calculation of the nonlinear model of horizontal wells in fractured-vuggy tight fractal reservoirs (Albinali et al, 2016;de Swaan, 2016;Noetinger et al, 2001Noetinger et al, , 2016. The reason why we apply fractal theory to deal with fracture system is to study the initial distribution of fractures in space, so we considered the fractal characteristics of the fracture in space, but not in time.…”

Section: Fractal Characteristics Of the Fracture Systemmentioning

confidence: 99%

Characteristics of transient pressure performance of horizontal wells in fractured-vuggy tight fractal reservoirs considering nonlinear seepage

Jiang

Zhang

Cui

et al. 2019

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Since the classical seepage theory has limitations in characterizing the heterogeneity of fractured-vuggy tight reservoirs, well test interpretation results are not consistent with actual production by far. Based on the nonlinear percolation theory, a new nonlinear seepage equation considering the boundary layer and yield stress was derived to describe the seepage characteristics of dense matrix blocks and the stress sensitivity and fractal features of fracture systems were characterized by applying the fractal theory. Thus, the nonlinear model of a horizontal well in a fractured-vuggy tight fractal reservoir was established naturally. Then the finite element method was applied to solve the bottom hole pressure based on the processing of internal boundary conditions. After solving the model, the seepage characteristics of different models were summarized by analyzing the bottom hole pressure dynamic curves and the sensitivity analysis of multiple parameters such the nonlinear parameter and fractal index were conducted. Finally, the practicality of the model was proved through a field application. The results show that the pressure dynamic curves can be divided into nine flow stages and the increase of the nonlinear parameter will cause the intensity of the cross flow from matrix blocks to the fracture system to decrease. The fractal index is irrelevant to the intensity of the cross flow while it decides the upwarping degree of the curve at the middle and late flow stages. On the basis of the results of the field application, it can be concluded that the model fits well with actual production and the application of this model can improve the accuracy of well test interpretation.

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Section: Fractal Characteristics Of the Fracture Systemmentioning

confidence: 99%

Characteristics of transient pressure performance of horizontal wells in fractured-vuggy tight fractal reservoirs considering nonlinear seepage

Jiang

Zhang

Cui

et al. 2019

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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“…Many scholars have carried out related researches on naturally fractured reservoir based on continuous assumption some dual media models were generated, including Warren-Root (1963) model, Kazemi (1968) model and de Swaan (1976) model. Later, some scholars began to introduce fractal models to study the characteristics of fractured reservoirs, where properties are scaled with distance to some reference point in the domain (Chang et al, 1990;Albinali et al, 2016;de Swaan, 2016). In recent years, numerical simulation attracts researchers' attention.…”

Section: Introductionmentioning

confidence: 99%

Performance of horizontal wells in composite tight gas reservoirs considering stress sensitivity

Zhao¹,

Du²

2019

Adv. Geo-Energ. Res.

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Tight gas reservoir (TGR) plays an important role in unconventional oil and gas resources. The existing seepage models for TGR rarely consider the effects of heterogeneity, stresssensitivity, and the unsteady fluid exchange between matrix and fracture. Heterogeneity is common for tight gas reservoir which should be carefully considered in geological model. The stress-sensitivity effect of fracture is an important factor influencing the transient flow behavior of TGR. Ultra-low porosity and permeability cause the unsteady flow between matrix and fractures systems. So this paper introduced a mathematical model for the horizontal well in a dual-porosity composite tight gas reservoir with considering the stress-sensitivity effect and unsteady flow between matrix and fractures systems. Some mathematical methods including the finite Fourier cosine transform, perturbation technique, Laplace transform, superposition principle, Stehfest numerical inversion algorithm are used to solve the nonlinear partial differential equation. Different flow regimes are divided based on pressure transient analysis curves. The sensitivity analysis of related parameters is studied according to pressure transient analysis and rate transient analysis curves. The presented model and obtained results in this paper give better understanding on pressure and rate transient behaviors of composite TGR.

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“…During the past decades, many scholars have contributed to analyzing production and pressure performance, as it is an essential part of reservoir evaluation. Pressure performance analysis also constitutes the basis for production analysis (Mcguire and Sikora, 1960;Raghavan et al, 1972;Albinali et al, 2016;de Swaan, 2016).…”

Section: Nomenclaturementioning

confidence: 99%

Production analysis for fractured vertical well in rectangular coal reservoirs

Dong

2018

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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As one kind of unconventional natural gas, coalbed methane is an important energy resource that is subject to active research. Gas exists in coalbed methane reservoirs in two forms: free gas and adsorbed gas. In the course of coalbed methane production, the reservoir experiences pressure decrease, desorption, diffusion, and seepage. Previous models of coalbed methane production were mainly concerned with circular boundaries. However, field tests revealed that some fractured wells possess the characteristics of rectangular boundaries. For fractured rectangular coalbed methane reservoirs, it is necessary to deal with the four boundaries with mirror image theory, which complicates calculations. In addition, the desorption and adsorption process of coalbed methane exerts a strong effect on the seepage process. Furthermore, the complexity of the rectangular coal seam embedded with the finite-conductivity fracture results in a significant computational challenge. For the first time, this paper presented a fast analytical solution for a finite-conductivity fractured vertical well model with either rectangular closed or constant-pressure boundaries in the coal seam. On the basis of the Fick diffusion law and the Darcy seepage law, a mathematical model that considers diffusion in matrix and seepage within natural fractures was established. Then, we integrated the fracture conductivity function method with the hydraulic fracture model to greatly increase computational efficiency. The analytical solutions were validated against a numerical simulation. Parameter sensitivity analysis reveals that interporosity coefficient and storage coefficient, respectively, affect the appearance time and degree of desorption and diffusion. Desorption coefficient mainly describes the capacity of desorption and diffusion. Well storage coefficient, conductivity factor, and skin factor mainly affect the early stage of production. Finally, the proposed solutions were applied to field history match. The model developed is applicable to production analysis and well testing for coalbed methane reservoirs. The new proposed model extended flow mechanism of coalbed methane, and provided a better production and pressure forecast for coalbed methane reservoirs. In addition, the analytical solutions can be used to generate type curves for fractured vertical wells with finite conductivity and in the rectangular boundary, and provide a sound theoretical basis for well tests in the coal seam. The model is also applicable to other types of unconventional gas reservoirs, such as gas shales, in which the same processes are present.

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Modeling of 1D Anomalous Diffusion in Fractured Nanoporous Media

Cited by 22 publications

References 28 publications

Characteristics of transient pressure performance of horizontal wells in fractured-vuggy tight fractal reservoirs considering nonlinear seepage

Characteristics of transient pressure performance of horizontal wells in fractured-vuggy tight fractal reservoirs considering nonlinear seepage

Performance of horizontal wells in composite tight gas reservoirs considering stress sensitivity

Production analysis for fractured vertical well in rectangular coal reservoirs

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