scholarly journals Image processing for fractal geometry-based discrete fracture network modeling input data: A methodological approach

2018 ◽  
Vol 62 (1) ◽  
pp. 1-14
Author(s):  
Dorottya Kovács ◽  
Gergely Dabi ◽  
Balázs Vásárhelyi
Keyword(s):  
Image Processing ◽  
Fractal Geometry ◽  
Methodological Approach ◽  
Damage Zone ◽  
Data Retrieval ◽  
Fracture Network ◽  
Discrete Fracture Network ◽  
Environmental Damage ◽  
Fracture Length ◽  
Discrete Fracture

With the intent of making data acquisition for fractal geometry-based discrete fracture network (DFN) modeling time-efficient and automatized, a new method was established. For the automation of data retrieval from the images of the studied surfaces, a series of image-processing operations and MATLAB algorithms have been developed. The method allows the retrieval of more than 1,000 fracture-length data/cm2 of one sample in several minutes. This methodology tends to be a useful tool in studies of fracture network geometries. DFN models of a supposed excavated and/or environmental damage zone, designed with the use of data supplied by the above method, are presented in this work as an example.

scholarly journals Enhancing fracture-network characterization and discrete-fracture-network simulation with high-resolution surveys using unmanned aerial vehicles

2020 ◽  
Vol 28 (7) ◽  
pp. 2285-2302
Author(s):  
Mahawa Essa Mabossani Akara ◽  
Donald M. Reeves ◽  
Rishi Parashar
Keyword(s):  
Fluid Flow ◽  
Fracture Network ◽  
Pumping Test ◽  
Discrete Fracture Network ◽  
Granitic Rocks ◽  
Equivalent Permeability ◽  
Fracture Length ◽  
Discrete Fracture ◽  
Network Scale ◽  
Aperture Scaling

Abstract A workflow is presented that integrates unmanned aerial vehicle (UAV) imagery with discrete fracture network (DFN) geometric characterization and quantification of fluid flow. The DFN analysis allows for reliable characterization and reproduction of the most relevant features of fracture networks, including: identification of orientation sets and their characteristics (mean orientation, dispersion, and prior probability); scale invariance in distributions of fracture length and spatial location/clustering; and the distribution of aperture values used to compute network-scale equivalent permeability. A two-dimensional DFN-generation approach honors field data by explicitly reproducing observed multi-scale fracture clustering using a multiplicative cascade process and power law distribution of fracture length. The influence of aperture on network-scale equivalent permeability is investigated using comparisons between a sublinear aperture-to-length relationship and constant aperture. To assess the applicability of the developed methodology, DFN flow simulations are calibrated to pumping test data. Results suggest that even at small scales, UAV surveys capture the essential geometrical properties required for fluid flow characterization. Both the constant and sublinear aperture scaling approaches provide good matches to the pumping test results with only minimal calibration, indicating that the reproduced networks sufficiently capture the geometric and connectivity properties characteristic of the granitic rocks at the study site. The sublinear aperture scaling case honors the directions of dominant fractures that play a critical role in connecting fracture clusters and provides a realistic representation of network permeability.

scholarly journals A Fractal Discrete Fracture Network Based Model for Gas Production from Fractured Shale Reservoirs

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1857
Author(s):  
Bowen Hu ◽  
Jianguo Wang ◽  
Zhanguo Ma
Keyword(s):  
Fractal Dimension ◽  
Numerical Model ◽  
Pore Size ◽  
Fracture Network ◽  
Gas Production ◽  
Discrete Fracture Network ◽  
Fracture Permeability ◽  
Fracture Length ◽  
Discrete Fracture ◽  
Shale Reservoir

A fractal discrete fracture network based model was proposed for the gas production prediction from a fractured shale reservoir. Firstly, this model was established based on the fractal distribution of fracture length and a fractal permeability model of shale matrix which coupled the multiple flow mechanisms of slip flow, Knudsen diffusion, surface diffusion, and multilayer adsorption. Then, a numerical model was formulated with the governing equations of gas transport in both a shale matrix and fracture network system and the deformation equation of the fractured shale reservoir. Thirdly, this numerical model was solved within the platform of COMSOL Multiphysics (a finite element software) and verified through three fractal discrete fracture networks and the field data of gas production from two shale wells. Finally, the sensitivity analysis was conducted on fracture length fractal dimension, pore size distribution, and fracture permeability. This study found that cumulative gas production increases up to 113% when the fracture fractal length dimension increases from 1.5 to the critical value of 1.7. The gas production rate declines more rapidly for a larger fractal dimension (up to 1.7). Wider distribution of pore sizes (either bigger maximum pore size or smaller minimum pore size or both) can increase the matrix permeability and is beneficial to cumulative gas production. A linear relationship is observed between the fracture permeability and the cumulative gas production. Thus, the fracture permeability can significantly impact shale gas production.

Integrated deterministic and predictive discrete fracture network modeling for an Eocene carbonate reservoir, Bengal Basin, India

2019 ◽  
Vol 38 (4) ◽  
pp. 274-279
Author(s):  
Prashant K. Dubey ◽  
Sushil Kumar ◽  
Khushboo Havelia ◽  
Savitri Yadav
Keyword(s):  
Fracture Network ◽  
Seismic Inversion ◽  
Carbonate Reservoir ◽  
Discrete Fracture Network ◽  
Earth Model ◽  
Bengal Basin ◽  
Fracture Porosity ◽  
Fracture Length ◽  
Discrete Fracture ◽  
Porosity And Permeability

Prediction of fracture porosity and permeability remains a challenge for fractured carbonate reservoirs. As natural fractures are heterogeneous and subseismic in scale, core data and image logs only provide partially sampled data, leading to sparse information on fracture length, height, orientation, spacing, and aperture. In the present study, an integrated discrete fracture network was generated that is capable of predicting fracture porosity in Eocene carbonates of the Bengal Basin in northeastern India. The predictive fracture modeling method used 3D kinematic and geomechanical restoration of interpreted seismic horizons to estimate infinitesimal stress and strain values and to characterize associated fracture sets. Seismic attribute analysis was used to extract faults and fractures from an ant-track cube, which provided sharper definition of discontinuities seen in conventional curvature attribute data. An integrated discrete fracture model was created using information from seismic attributes, seismic inversion, and strain distribution to determine fracture intensity. Faults and fractures that are seismically resolved were statistically analyzed, which indicated that spatial distribution of fracture length follows a power law. Based on theoretical concepts of fracture mechanics, linear aperture-to-length scaling was used to characterize aperture population. A present-day geomechanical earth model was used to identify open fracture sets. This model shows that northeast–southwest-oriented fracture sets are critically stressed and will contribute to porosity and permeability. Criticality of fractures to shear failure was analyzed by computing geomechanical parameters — slip stability and dilation tendency, based on the direction and magnitude of far-field stresses. Fractures with slip and dilation tendencies greater than 0.6 in the modeled discrete fracture network were taken as inputs for porosity and permeability estimation.

scholarly journals Characterizing Reactive Transport Behavior in a Three-Dimensional Discrete Fracture Network

2021 ◽  
Author(s):  
Thomas Sherman ◽  
Guillem Sole-Mari ◽  
Jeffrey Hyman ◽  
Matthew R. Sweeney ◽  
Daniel Vassallo ◽  
...  
Keyword(s):  
Reactive Transport ◽  
Three Dimensional ◽  
Fracture Network ◽  
Discrete Fracture Network ◽  
Transport Behavior ◽  
Discrete Fracture
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