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

2014 ◽  
Author(s):  
Yanbin Zhang ◽  
Neha Bansal ◽  
Yusuke Fujita ◽  
Akhil Datta-gupta ◽  
Michael J. King ◽  
...  
Keyword(s):  
Performance Assessment ◽  
Shale Gas ◽  
Time Of Flight ◽  
Gas Reservoirs ◽  
Fast Marching ◽  
Spatial Coordinate ◽  
Shale Gas Reservoirs ◽  
And Performance ◽  
Diffusive Time

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.

Integration of Shale-Gas-Production Data and Microseismic for Fracture and Reservoir Properties With the Fast Marching Method

SPE Journal ◽  
2014 ◽  
Vol 20 (02) ◽  
pp. 347-359 ◽  
Author(s):  
Jiang Xie ◽  
Changdong Yang ◽  
Neha Gupta ◽  
Michael J. King ◽  
Akhil Datta-Gupta
Keyword(s):  
Shale Gas ◽  
Gas Production ◽  
Production Data ◽  
Hydraulic Fractures ◽  
Fast Marching Method ◽  
Gas Reservoirs ◽  
Fast Marching ◽  
Drainage Volume ◽  
Shale Gas Reservoirs ◽  
Marching Method

Summary We present a novel approach to calculate drainage volume and well performance in shale gas reservoirs by use of the fast marching method (FMM) combined with a geometric pressure approximation. Our approach can fully account for complex fracture-network geometries associated with multistage hydraulic fractures and their impact on the well pressure and rates. The major advantages of our proposed approach are its simplicity, intuitive appeal, and computational efficiency. For example, we can compute and visualize the time evolution of the well-drainage volume for multimillion-cell geologic models in seconds without resorting to reservoir simulation. A geometric approximation of the drainage volume is then used to compute the well rates and the reservoir pressure. The speed and versatility of our proposed approach make it ideally suited for parameter estimation by means of the inverse modeling of shale-gas performance data. We use experimental design to perform the sensitivity analysis to identify the “heavy hitters” and a genetic algorithm (GA) to calibrate the relevant fracture and matrix parameters in shale-gas reservoirs by history matching of production data. In addition to the production data, microseismic information is used to help us constrain the fracture extent and orientation and to estimate the stimulated reservoir volume (SRV). The proposed approach is applied to a fractured shale-gas well. The results clearly show reduced ranges in the estimated fracture parameters and SRV, leading to improved forecasting and reserves estimation.

Development and Application of Fast Simulation Based on the PSS Pressure as a Spatial Coordinate

2021 ◽  
Author(s):  
Kenta Nakajima ◽  
Michael King
Keyword(s):  
Eikonal Equation ◽  
Time Of Flight ◽  
Fast Marching Method ◽  
Reservoir Model ◽  
Fast Marching ◽  
Flow Equations ◽  
Spatial Coordinate ◽  
Single Well ◽  
Marching Method ◽  
Diffusive Time

Abstract Recent studies have shown the utility of the Fast Marching Method and the Diffusive Time of Flight for the rapid simulation and analysis of Unconventional reservoirs, where the time scale for pressure transients are long and field developments are dominated by single well performance. We show that similar fast simulation and multi-well modeling approaches can be developed utilizing the PSS pressure as a spatial coordinate, providing an extension to both Conventional and Unconventional reservoir analysis. We reformulate the multi-dimensional multi-phase flow equations using the PSS pressure drop as a spatial coordinate. Properties are obtained by coarsening and upscaling a fine scale 3D reservoir model, and are then used to obtain fast single well simulation models. We also develop new 1D solutions to the Eikonal equation that are aligned with the PSS discretization, which better represent superposition and finite sized boundary effects than the original 3D Eikonal equation. These solutions allow the use of superposition to extend the single well results to multiple wells. The new solutions to the Eikonal equation more accurately represent multi-fracture interference for a horizontal MTFW well, the effects of strong heterogeneity, and finite reservoir extent than those obtained by the Fast Marching Method. The new methodologies are validated against a series of increasingly heterogeneous synthetic examples, with vertical and horizontal wells. We find that the results are systematically more accurate than those based upon the Diffusive Time of Flight, especially as the wells are placed closer to the reservoir boundary or as heterogeneity increases. The approach is applied to the Brugge benchmark study. We consider the history matching stage of the study and utilize the multi-well fast modeling approach to determine the rank quality of the 100+ static realizations provided in the benchmark dataset against historical data. The multi-well calculation uses superposition to obtain a direct calculation of the interaction of the rates and pressures of the wells without the need to explicitly solve flow equations within the reservoir model. The ranked realizations are then compared against full field simulation to demonstrate the significant reduction in simulation cost and the corresponding ability to explore the subsurface uncertainty more extensively. We demonstrate two completely new methods for rapid reservoir analysis, based upon the use of the PSS pressure as a spatial coordinate. The first approach demonstrates the utility of rapid single well flow simulation, with improved accuracy compared to the use of the Diffusive Time of Flight. We are also able to reformulate and solve the Eikonal equation in these coordinates, giving a rapid analytic method of transient flow analysis for both single and multi-well modeling.

PERFORMANCE ANALYSIS OF MULTI-FRACTURED HORIZONTAL WELLS WITH COMPLEX FRACTURE NETWORKS IN SHALE GAS RESERVOIRS

2019 ◽  
Vol 22 (3) ◽  
pp. 299-320 ◽  
Author(s):  
Guanglong Sheng ◽  
Ting Xu ◽  
Feifei Gou ◽  
Yuliang Su ◽  
Wendong Wang ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Shale Gas ◽  
Horizontal Wells ◽  
Fracture Networks ◽  
Gas Reservoirs ◽  
Complex Fracture ◽  
Shale Gas Reservoirs ◽  
Fractured Horizontal Wells

Uncertainty Assessment of Production Performance for Shale-Gas Reservoirs

2013 ◽  
Author(s):  
Jiang Xie ◽  
Seong H. Lee ◽  
Zhiming Wang ◽  
Xian-Huan Wen
Keyword(s):  
Shale Gas ◽  
Uncertainty Assessment ◽  
Production Performance ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs

Geomechanical Characterisation and Modelling Help to Unlock Shale Gas Reservoirs in the Southern Sichuan Basin

2013 ◽  
Author(s):  
Roger Yuan ◽  
Fa Dwan ◽  
Navpreet Singh ◽  
Liang Jin ◽  
Danny Soo ◽  
...  
Keyword(s):  
Shale Gas ◽  
Sichuan Basin ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs

Comparison of Marine and Continental Shale Gas Reservoirs and Their Gas-Bearing Properties in China: The Examples of the Longmaxi and Shahezi Shales

2021 ◽  
Author(s):  
Dianshi Xiao ◽  
Shuangfang Lu ◽  
Mingli Shao ◽  
Nengwu Zhou ◽  
Renwen Zhao ◽  
...  
Keyword(s):  
Shale Gas ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs ◽  
Gas Bearing

scholarly journals Prediction of Shale Gas Reservoirs Using Fluid Mobility Attribute Driven by Post-Stack Seismic Data: A Case Study from Southern China

2020 ◽  
Vol 11 (1) ◽  
pp. 219
Author(s):  
Jing Zeng ◽  
Alexey Stovas ◽  
Handong Huang ◽  
Lixia Ren ◽  
Tianlei Tang
Keyword(s):  
Shale Gas ◽  
Seismic Data ◽  
Spectral Decomposition ◽  
Southern China ◽  
Gas Reservoirs ◽  
Seismic Attribute ◽  
Longmaxi Formation ◽  
Shale Gas Reservoirs ◽  
The Sichuan Basin ◽  
Shale Reservoirs

Paleozoic marine shale gas resources in Southern China present broad prospects for exploration and development. However, previous research has mostly focused on the shale in the Sichuan Basin. The research target of this study is expanded to the Lower Silurian Longmaxi shale outside the Sichuan Basin. A prediction scheme of shale gas reservoirs through the frequency-dependent seismic attribute technology is developed to reduce drilling risks of shale gas related to complex geological structure and low exploration level. Extracting frequency-dependent seismic attribute is inseparable from spectral decomposition technology, whereby the matching pursuit algorithm is commonly used. However, frequency interference in MP results in an erroneous time-frequency (TF) spectrum and affects the accuracy of seismic attribute. Firstly, a novel spectral decomposition technology is proposed to minimize the effect of frequency interference by integrating the MP and the ensemble empirical mode decomposition (EEMD). Synthetic and real data tests indicate that the proposed spectral decomposition technology provides a TF spectrum with higher accuracy and resolution than traditional MP. Then, a seismic fluid mobility attribute, extracted from the post-stack seismic data through the proposed spectral decomposition technology, is applied to characterize the shale reservoirs. The application result indicates that the seismic fluid mobility attribute can describe the spatial distribution of shale gas reservoirs well without well control. Based on the seismic fluid mobility attribute section, we have learned that the shale gas enrich areas are located near the bottom of the Longmaxi Formation. The inverted velocity data are also introduced to further verify the reliability of seismic fluid mobility. Finally, the thickness map of gas-bearing shale reservoirs in the Longmaxi Formation is obtained by combining the seismic fluid mobility attribute with the inverted velocity data, and two favorable exploration areas are suggested by analyzing the thickness, structure, and burial depth. The present work can not only be used to evaluate shale gas resources in the early stage of exploration, but also help to design the landing point and trajectory of directional drilling in the development stage.

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