Efficient Coupled Multiphase-Flow and Geomechanics Modeling of Well Performance and Stress Evolution in Shale-Gas Reservoirs Considering Dynamic Fracture Properties

SPE Journal ◽  
2020 ◽  
Vol 25 (03) ◽  
pp. 1523-1542 ◽  
Author(s):  
Lijun Liu ◽  
Yongzan Liu ◽  
Jun Yao ◽  
Zhaoqin Huang
Keyword(s):  
Multiphase Flow ◽  
Dynamic Fracture ◽  
Shale Gas ◽  
Hydraulic Fractures ◽  
Stress Evolution ◽  
Well Performance ◽  
Gas Reservoirs ◽  
Fracture Properties ◽  
Shale Gas Reservoirs ◽  
Proposed Model

Summary Significant conductivity losses of both propped hydraulic fractures and unpropped natural fractures are widely observed by laboratory experiments and field studies in shale-gas reservoirs. Previous studies have not well-considered the effects of dynamic fracture properties, which limit the accurate prediction of well performance and stress evolution. In this study, an efficient coupled flow and geomechanics model is proposed to characterize the dynamic fracture properties and examine their effects on well performance and stress evolution in complex fractured shale-gas reservoirs. In our proposed model, a unified compositional model with nonlinear transport mechanisms is used to accurately describe multiphase flow in shale formations. The embedded discrete fracture model (EDFM) is used to explicitly model the complex fracture networks. Different fracture constitutive models are implemented to describe the dynamic properties of hydraulic fractures and natural fractures, respectively. The finite-volume method (FVM) and finite-element method (FEM) are used for the space discretization of flow and geomechanics equations, respectively, and the coupled problem is solved by the fixed-stress split iterative method. The coupled model is validated against classical analytical solutions. After that, the proposed model is used to investigate the effects of hydraulic-fracture and natural-fracture properties on production behavior as well as pressure and stress evolution of shale-gas reservoirs. With the dynamic fracture properties incorporated, our model can predict the well production more accurately, and provide more realistic stress evolution that is essential for the design and optimization of refracturing and infill-well drilling.

From Streamlines to Fast Marching: Rapid Simulation and Performance Assessment of Shale-Gas Reservoirs by Use of Diffusive Time of Flight as a Spatial Coordinate

SPE Journal ◽  
2016 ◽  
Vol 21 (05) ◽  
pp. 1883-1898 ◽  
Author(s):  
Yanbin Zhang ◽  
Neha Bansal ◽  
Yusuke Fujita ◽  
Akhil Datta-Gupta ◽  
Michael J. King ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Performance Assessment ◽  
Shale Gas ◽  
History Matching ◽  
Well Performance ◽  
Gas Reservoirs ◽  
Fast Marching ◽  
Shale Gas Reservoirs ◽  
And Performance ◽  
Diffusivity Equation

Summary Current industry practice for characterization and assessment of unconventional reservoirs mostly uses empirical decline-curve analysis or analytic rate- and pressure-transient analysis. High-resolution numerical simulation with local perpendicular bisector (PEBI) grids and global corner-point grids has also been used to examine complex nonplanar fracture geometry, interaction between hydraulic and natural fractures, and implications for the well performance. Although the analytic tools require many simplified assumptions, numerical-simulation techniques are computationally expensive and do not provide the more-geometric understanding derived from the depth-of-investigation (DOI) and drainage-volume calculations. We propose a novel approach for rapid field-scale performance assessment of shale-gas reservoirs. Our proposed approach is dependent on a high-frequency asymptotic solution of the diffusivity equation in heterogeneous reservoirs and serves as a bridge between simplified analytical tools and complex numerical simulation. The high-frequency solution leads to the Eikonal equation (Paris and Hurd 1969), which is solved for a “diffusive time of flight” (DTOF) that governs the propagation of the “pressure front” in the reservoir. The Eikonal equation can be solved by use of the fast-marching method (FMM) to determine the DTOF, which generalizes the concept of DOI to heterogeneous and fractured reservoirs. It provides an efficient means to calculate drainage volume, pressure depletion, and well performance and can be significantly faster than conventional numerical simulation. More importantly, in a manner analogous to streamline simulation, the DTOF can also be used as a spatial coordinate to reduce the 3D diffusivity equation to a 1D equation, leading to a comprehensive simulator for rapid performance prediction of shale-gas reservoirs. The speed and versatility of our proposed method makes it ideally suited for high-resolution reservoir characterization through integration of static and dynamic data. The major advantages of our proposed approach are its simplicity, intuitive appeal, and computational efficiency. We demonstrate the power and utility of our method by use of a field example that involves history matching, uncertainty analysis, and performance assessment of a shale-gas reservoir in east Texas. A sensitivity study is first performed to systematically identify the “heavy hitters” affecting the well performance. This is followed by history matching and an uncertainty analysis to identify the fracture parameters and the stimulated-reservoir volume. A comparison of model predictions with the actual well performance shows that our approach is able to reliably predict the pressure depletion and rate decline.

Sensitivity Studies of Horizontal Wells with Hydraulic Fractures in Shale Gas Reservoirs

2009 ◽  
Author(s):  
Xu Zhang ◽  
Changan Du ◽  
Franz Deimbacher ◽  
Martin Crick ◽  
Arvind Harikesavanallur
Keyword(s):  
Shale Gas ◽  
Horizontal Wells ◽  
Hydraulic Fractures ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs ◽  
Sensitivity Studies

Modeling Well Performance in Shale-Gas Reservoirs

2009 ◽  
Author(s):  
C.L. Cipolla ◽  
E.P. Lolon ◽  
J.C. Erdle ◽  
V. Tathed
Keyword(s):  
Shale Gas ◽  
Well Performance ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs

Numerical Simulation of Shale Gas Production

2011 ◽  
Vol 402 ◽  
pp. 804-807 ◽  
Author(s):  
Song Ru Mu ◽  
Shi Cheng Zhang
Keyword(s):  
Shale Gas ◽  
Simulation Models ◽  
Fracture Network ◽  
Gas Production ◽  
Wire Mesh ◽  
Well Performance ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs ◽  
Shale Reservoirs ◽  
Fracture Mapping

Shale gas reservoirs require a large fracture network to maximize well performance. Microseismic fracture mapping has shown that large fracture networks can be generated in many shale reservoirs. The application of microseismic fracture mapping measurements requires estimation of the structure of the complex hydraulic fracture or the volume of the reservoir that has been stimulated by the fracture treatment. There are three primary approaches used to incorporate microseismic measurements into reservoir simulation models: discrete modeling of the complex fracture network, wire-mesh model, and dual porosity model. This paper discuss the different simulation model, the results provided insights into effective stimulation designs and flow mechanism for shale gas reservoirs.

scholarly journals History Matching and Forecast of Shale Gas Production Considering Hydraulic Fracture Closure

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1634 ◽  
Author(s):  
Juhyun Kim ◽  
Youngjin Seo ◽  
Jihoon Wang ◽  
Youngsoo Lee
Keyword(s):  
Shale Gas ◽  
Hydraulic Fracture ◽  
History Matching ◽  
Gas Flow ◽  
Fluid Pressure ◽  
Gas Production ◽  
Hydraulic Fractures ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs ◽  
Fracture Closure

Most shale gas reservoirs have extremely low permeability. Predicting their fluid transport characteristics is extremely difficult due to complex flow mechanisms between hydraulic fractures and the adjacent rock matrix. Recently, studies adopting the dynamic modeling approach have been proposed to investigate the shape of the flow regime between induced and natural fractures. In this study, a production history matching was performed on a shale gas reservoir in Canada’s Horn River basin. Hypocenters and densities of the microseismic signals were used to identify the hydraulic fracture distributions and the stimulated reservoir volume. In addition, the fracture width decreased because of fluid pressure reduction during production, which was integrated with the dynamic permeability change of the hydraulic fractures. We also incorporated the geometric change of hydraulic fractures to the 3D reservoir simulation model and established a new shale gas modeling procedure. Results demonstrate that the accuracy of the predictions for shale gas flow improved. We believe that this technique will enrich the community’s understanding of fluid flows in shale gas reservoirs.

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