Modeling hydraulic fractures in finite difference simulators using amalgam LGR (Local Grid Refinement)

2012 ◽  
Author(s):  
Sherif Sayed Abdle Moneim ◽  
Reda Rabee ◽  
Ahmed Mahmoud Shehata ◽  
Ahmed M. Aly
Keyword(s):  
Finite Difference ◽  
Hydraulic Fractures ◽  
Grid Refinement ◽  
Local Grid Refinement ◽  
Local Grid

Finite‐difference simulation of elastic waves propagation in multiscale media on the base of local grid refinement

2008 ◽  
Author(s):  
Jerome Guilbot ◽  
Valery G. Khaidukov ◽  
Eugene Landa ◽  
Galina V. Reshetova ◽  
Vladimir A. Tcheverda
Keyword(s):  
Finite Difference ◽  
Elastic Waves ◽  
Grid Refinement ◽  
Local Grid Refinement ◽  
Local Grid ◽  
Waves Propagation

Grid-Sensitivity Analysis and Comparison Between Unstructured Perpendicular Bisector and Structured Tartan/Local-Grid-Refinement Grids for Hydraulically Fractured Horizontal Wells in Eagle Ford Formation With Complicated Natural Fractures

SPE Journal ◽  
2016 ◽  
Vol 21 (06) ◽  
pp. 2260-2275 ◽  
Author(s):  
Jianlei Sun ◽  
David Schechter ◽  
Chung-Kan Huang
Keyword(s):  
Horizontal Wells ◽  
Work Flow ◽  
Hydraulic Fractures ◽  
Grid Refinement ◽  
Fracture Networks ◽  
Structured Grids ◽  
Local Grid Refinement ◽  
Production Behavior ◽  
Local Grid ◽  
Fractured Horizontal Wells

Summary In the context of modeling fractured horizontal wells, unstructured grids have been applied to generate simulation meshes for complex fracture networks. It is necessary to investigate how to choose an unstructured mesh to accurately simulate production performance. In this paper, a new unstructured gridding and discretization work flow is proposed to handle nonorthogonal and low-angle intersections of extensively clustered fractures with nonuniform apertures. The work flow is then validated with two models in terms of production behavior and central-processing-unit (CPU) performance: a synthetic model with one horizontal well and orthogonal intersected hydraulic fractures built by tartan grid, and a field-scale local-grid-refinement (LGR) model with three horizontal wells and irregular hydraulic fractures in a slightly dipping reservoir created by a commercial software plug-in. Good-quality matches are obtained between unstructured and structured grids in both pressure and production behavior. Sensitivity analysis of the meshing parameters suggests that refinement in the vicinity of fractures has improved both early and late production of a well, whereas background density has a dominant effect on the late production. Background-grid type and orientation have less influence as long as they have the same grid density. Fewer cells can be achieved by increasing reservoir-background size and size-progression ratio, replacing unstructured-background grids with structured grids, and reducing the complexity of the fracture networks without loss of the accuracy, resulting in improved CPU performance. This study applies unstructured grids to simulate multiple horizontal wells with complicated fracture networks, and provides detailed comparisons between unstructured and structured grids. Most importantly, it resolves the question regarding how to choose an appropriate mesh to yield both accurate results and high-quality CPU performance.

Improved Calculation of Wellblock Pressures for Numerical Simulation of Non-Newtonian Polymer Injection

SPE Journal ◽  
2021 ◽  
pp. 1-12
Author(s):  
Irfan Tai ◽  
Marie Ann Giddins ◽  
Ann Muggeridge
Keyword(s):  
Numerical Simulation ◽  
Oil Recovery ◽  
Polymer Solutions ◽  
Shear Thinning ◽  
Injection Well ◽  
Solution Viscosity ◽  
Grid Refinement ◽  
Equivalent Radius ◽  
Local Grid Refinement ◽  
Local Grid

Summary The viability of any enhanced-oil-recovery project depends on the ability to inject the displacing fluid at an economic rate. This is typically evaluated using finite-volume numerical simulation. These simulators calculate injectivity using the Peaceman method (Peaceman 1978), which assumes that flow is Newtonian. Most polymer solutions exhibit some degree of non-Newtonian behavior resulting in a changing polymer viscosity with distance from the injection well. For shear-thinning polymer solutions, conventional simulations can overpredict injection-well bottomhole pressure (BHP) by several hundred psi, unless a computationally costly local grid refinement is used in the near-wellboreregion. We show theoretically and numerically that the Peaceman pressure-equivalent radius, based on Darcy flow, is not correct when fluids are shear thinning, and derive an analytical expression for calculating the correct radius. The expression does not depend on any particular functional relationship between polymer-solution viscosity and velocity. We test it using the relationship described by the Meter equation (Meter and Bird 1964) and the Cannella et al. (1988) correlation. Numerical tests indicate that the solution provides a significant improvement in the accuracy of BHP calculations for conventional numerical simulation, reducing or removing the need for expensive local grid refinement around the well when simulating the injection of fluids with shear-thinningnon-Newtonianrheology.

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