Simulation of Matrix/Fracture Interaction in Low-Permeability Fractured Unconventional Reservoirs

Ding, Didier Yu; Farah, N.; Bourbiaux, B.; Wu, Yu‐Shu; Mestiri, Imen

doi:10.2118/182608-pa

Cited by 52 publications

(15 citation statements)

References 27 publications

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“…In recent years, numerical simulation attracts researchers' attention. It is able to consider more complicate situation of unconventional reservoirs using meshed numerical models (Wu et al, 2014;Noetinger, 2015;Ngo et al, 2017;Ding et al, 2018). However, analytical and semianalytical methods still need to be valued for their fast and low-cost advantages.…”

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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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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“…This can imply some numerical errors in the EDFM method because of the singular behavior in √ t of pressure close to a fracture is badly captured. In these cases, the MINC (Multiple Interacting Continua) methods for capturing short time behavior can be applied [43,44].…”

Section: Edfm Methodsmentioning

confidence: 99%

Fracture Detection and Numerical Modeling for Fractured Reservoirs

Zuo

Tan

et al. 2019

Energies

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The subsurface fractures could impact the fluid mechanisms dramatically, which makes the modeling of the hydraulic and natural fractures an essential step for fractured reservoirs simulations. However, because of the complexities of fracture patterns and distributions, it is difficult to detect and quantify the fracture networks. In this study, line detection techniques are designed and applied to quantify the fracture segments from fracture figures. Using this fracture detection algorithm, the fracture segments could be located by detecting the endpoints and the intersections of fractures, thus that the fracture patterns could be accurately captured and characterized. The proposed method is applied to two previous well-known field cases and the pressure distribution results are consistent with the micro-seismic data profiles. These two field cases are simulated and computed by using a semianalytical model and Embedded Discrete Fracture Model (EDFM) respectively. The third case is constructed by the fracture outcrop figure and simulated by a numerical simulator with EDFM implemented. The simulation results are accurate and clearly illustrate the important role fractures play in unconventional reservoirs. The technology proposed in this study could be used to quantify the fracture input data for reservoir simulations and be easily expanded for fracture detection and characterization problems in other fields.

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“…It should be pointed out that in order to improve the calculation accuracy of fracture-matrix exchange, the MINC modeling techniques and random walks methods were proposed in the literature [30,31].…”

Section: Appendix C Numerical Solution For the Unsteady State Non-eqmentioning

confidence: 99%

Investigation of Analysis Methods for Pulse Decay Tests Considering Gas Adsorption

2019

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The pulse decay test is the main method employed to determine permeability for tight rocks, and is widely used. The testing gas can be strongly adsorbed on the pore surface of unconventional reservoir cores, such as shale and coal rock. However, gas adsorption has not been well considered in analysis pulse decay tests. In this study, the conventional flow model of adsorbed gas in porous media was modified by considering the volume of the adsorbed phase. Then, pulse decay tests of equilibrium sorption, unsteady state and pseudo-steady-state non-equilibrium sorption models, were analyzed by simulations. For equilibrium sorption, it is found that the Cui-correction method is excessive when the adsorbed phase volume is considered. This method is good at very low pressure, and is worse than the non-correction method at high pressure. When the testing pressure and Langmuir volume are large and the vessel volumes are small, a non-negligible error exists when using the Cui-correction method. If the vessel volumes are very large, gas adsorption can be ignored. For non-equilibrium sorption, the pulse decay characteristics of unsteady state and pseudo-steady-state non-equilibrium sorption models are similar to those of unsteady state and pseudo-steady-state dual-porosity models, respectively. When the upstream and downstream pressures become equal, they continue to decay until all of the pressures reach equilibrium. The Langmuir volume and pressure, the testing pressure and the porosity, affect the pseudo-storativity ratio and the pseudo-interporosity flow coefficient. Their impacts on non-equilibrium sorption models are similar to those of the storativity ratio and the interporosity flow coefficient in dual-porosity models. Like dual-porosity models, the pseudo-pressure derivative can be used to identify equilibrium and non-equilibrium sorption models at the early stage, and also the unsteady state and pseudo-steady-state non-equilibrium sorption models at the late stage. To identify models using the pseudo-pressure derivative at the early stage, the suitable vessel volumes should be chosen according to the core adsorption property, porosity and the testing pressure. Finally, experimental data are analyzed using the method proposed in this study, and the results are sufficient.

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Simulation of Matrix/Fracture Interaction in Low-Permeability Fractured Unconventional Reservoirs

Cited by 52 publications

References 27 publications

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

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

Fracture Detection and Numerical Modeling for Fractured Reservoirs

Investigation of Analysis Methods for Pulse Decay Tests Considering Gas Adsorption

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