Improved Numerical Simulation for Shale Gas Reservoirs

2014 ◽  
Author(s):  
Chaohua Guo ◽  
Mingzhen Wei ◽  
Haowei Chen ◽  
Xiaoming He ◽  
Baojun Bai
Keyword(s):  
Numerical Simulation ◽  
Shale Gas ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs

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.

scholarly journals Numerical simulation of gas transport mechanisms in tight shale gas reservoirs

2013 ◽  
Vol 10 (4) ◽  
pp. 528-537 ◽  
Author(s):  
Jun Yao ◽  
Hai Sun ◽  
Dong-yan Fan ◽  
Chen-chen Wang ◽  
Zhi-xue Sun
Keyword(s):  
Numerical Simulation ◽  
Shale Gas ◽  
Gas Transport ◽  
Transport Mechanisms ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs

A Simple Method for Quantifying Inter-Well Communication Using Production Data from Single-Phase Shale Gas Reservoirs

2021 ◽  
Author(s):  
Hamidreza Hamdi ◽  
Hamid Behmanesh ◽  
Christopher R. Clarkson
Keyword(s):  
Numerical Simulation ◽  
Shale Gas ◽  
Analytical Method ◽  
Single Phase ◽  
Material Balance ◽  
Production Data ◽  
Hydraulic Fractures ◽  
Gas Reservoirs ◽  
Simple Method ◽  
Shale Gas Reservoirs

Abstract Hydraulic fracture/reservoir properties and fluid-in-place can be quantified by using rate-transient analysis (RTA) techniques applied to flow rates/pressures gathered from multi-fractured horizontal wells (MFHWs) completed in unconventional reservoirs. These methods are commonly developed for the analysis of production data from single wells without considering communication with nearby wells. However, in practice, wells drilled from the same pad can be in strong hydraulic communication with each other. This study aims to develop the theoretical basis for analyzing production data from communicating MFHWs completed in single-phase shale gas reservoirs. A simple and practical semi-analytical method is developed to quantify the communication between wells drilled from the same pad by analyzing online production data from the individual wells. This method is based on the communicating tanks model and employs the concepts of macroscopic material balance and the succession of pseudo-steady states. A set of nonlinear ordinary differential equations (ODEs) are generated and solved simultaneously using the efficient Adams-Bashforth-Moulton algorithm. The accuracy of the solutions is verified against robust numerical simulation. In the first example provided, a MFHW well-pair is presented where the wells are communicating through primary hydraulic fractures with different communication strengths. In the subsequent examples, the method is extended to consider production data from a three-well and a six-well pad with wine-rack-style completions. The developed model is flexible enough to account for asynchronous wells that are producing from distinct reservoir blocks with different fracture/rock properties. For all the studied cases, the semi-analytical method closely reproduces the results of fully numerical simulation. The results demonstrate that, in some cases, when new wells start to produce, the production rates of existing wells can drop significantly. The amount of productivity loss is a direct function of the communication strengths between the wells. The new method can accurately quantify the communication strength between wells through transmissibility multipliers between the hydraulic fractures that are adjusted to match individual well production data. In this study, a new simple and efficient semi-analytical method is presented that can be used to analyze online production data from multiple wells drilled from a pad simultaneously with minimal computation time. The main advantage of the developed method is its scalability, where additional wells can be added to the system very easily.

Improved Numerical Simulation for Shale Gas Reservoirs

2014 ◽  
Author(s):  
Chaohua Guo ◽  
Mingzhen Wei ◽  
Haowei Chen ◽  
Xiaoming He ◽  
Baojun Bai
Keyword(s):  
Numerical Simulation ◽  
Shale Gas ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs
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