Haibin Di | Georgia Institute of Technology (original) (raw)

Papers by Haibin Di

GEOPHYSICS, 2015

Fracture characterization is fundamental to the reliable prediction of fractured reservoirs; howe... more Fracture characterization is fundamental to the reliable prediction of fractured reservoirs; however, it is difficult and expensive to obtain detailed fracture information required for reservoir prediction due to the lack of direct observational data in the subsurface. Here we develop seismic analysis methods to characterize fractured reservoirs based on reflection geometry related to bending and shearing of reservoir formations. Among various geometric attributes, we focus on extreme curvature and extreme flexure that are considered effective at detecting fractures. Extreme curvature refers to the signed absolute maximum curvature at a specific azimuth where the curve shape is the tightest, whereas extreme flexure refers to the signed absolute maximum gradient of curvature at a specific azimuth where the curve shape changes the most. We implement new algorithms based on analytical equations to calculate extreme curvature and extreme flexure along with the corresponding azimuth from 3D seismic data. Results from 3D seismic surveys demonstrate that the new algorithms help resolve structural details that are otherwise not easily discernible from regular amplitude and conventional attributes. Most importantly, the algorithms hold the potential to volumetrically detect and visualize fractures in an automatic and quantitative manner. We conclude that extreme curvature and extreme flexure attributes have important geologic implications for predicting fundamental fracture properties that are critical to fractured reservoir characterization in the subsurface.

Computers & Geosciences, 2014

In 3D seismic interpretation, both curvature and curvature gradient are useful seismic attributes... more In 3D seismic interpretation, both curvature and curvature gradient are useful seismic attributes for structure characterization and fault detection in the subsurface. However, the existing algorithms are computationally intensive and limited by the lateral resolution for steeply-dipping formations. This study presents new and robust volume-based algorithms that evaluate both curvature and curvature gradient attributes more accurately and effectively. The algorithms first instantaneously fit a local surface to seismic data and then compute attributes using the spatial derivatives of the built surface. Specifically, the curvature algorithm constructs a quadratic surface by using a rectangle 9-node grid cell, whereas the curvature gradient algorithm builds a cubic surface by using a diamond 13-node grid cell. A dip-steering approach based on 3D complex seismic trace analysis is implemented to enhance the accuracy of surface construction and to reduce computational time. Applications to two 3D seismic surveys demonstrate the accuracy and efficiency of the new curvature and curvature gradient algorithms for characterizing faults and fractures in fractured reservoirs.

Geophysical Prospecting, 2015

Most positive/negative curvature and flexure are among the most useful seismic attributes for det... more Most positive/negative curvature and flexure are among the most useful seismic attributes for detecting faults and fractures in the subsurface based on the geometry of seismic reflections. When applied to fracture characterization and modelling of a fractured reservoir, their magnitude and azimuth help quantify both the intensity and orientation of fracturing, respectively. However, previous efforts focus on estimating only the magnitude of both attributes, whereas their associated azimuth is ignored in three-dimensional (3D) seismic interpretation. This study presents an efficient algorithm for simultaneously evaluating both the magnitude and azimuth of most positive/negative curvature and flexure from 3D seismic data. The approach implemented in this study is analytically more accurate and computationally more efficient compared with the existing approach. The added value of extracting most positive/negative curvature and flexure is demonstrated through the application to a fractured reservoir at Teapot Dome (Wyoming). First, the newly extracted attributes make computer-aided fault/fracture decomposition possible. This allows interpreters to focus on one particular component for fracture characterization at a time, so that a composite fractured reservoir could be partitioned into different components for detailed analysis. Second, curvature/flexure azimuth allows interpreters to plot fracture histogram and/or rose diagram in an automatic and quantitative manner. Compared with the conventional plotting rose diagram based on manual measurements, automatic plotting is more efficient and offers unbiased insights into fracture systems by illuminating the most likely orientations of natural fractures in fractured reservoirs.

Computers & Geosciences, 2014

In a 3D seismic survey, detecting seismic discontinuities is vital to robust structural and strat... more In a 3D seismic survey, detecting seismic discontinuities is vital to robust structural and stratigraphic analysis in the subsurface. Previous methods have difficulty highlighting subtle discontinuities from seismic data in cases where the local amplitude variation is of non-zero mean. This study proposes implementing a gray-level transformation and the Canny edge detector for improved imaging of discontinuities. Specifically, the new process transforms seismic signals to be of zero mean and helps amplify subtle discontinuities, leading to an enhanced visualization for structural and stratigraphic details. Applications to various 3D seismic datasets demonstrate that the new algorithm helps better define channels, faults, and fractures than the traditional similarity, amplitude gradient, and semblance attributes.

SEG Technical Program Expanded Abstracts 2014, 2014

Seismic curvature is a useful second-order geometric attribute and has demonstrated its value for... more Seismic curvature is a useful second-order geometric attribute and has demonstrated its value for structure analysis, especially for fracture characterization in fractured reservoirs. Our recent efforts have been primarily focused on computing most extreme (signed maximum) curvature, whose magnitude and direction are usually associated with and indicative of the most-likely intensity and orientation of fractures in 3D space, respectively. This study presents an applicable equation for computing curvature attribute along any direction in 3D space, and an analytical algorithm that can simultaneously calculate the magnitude and azimuthal direction of the most extreme curvature at any location in the reservoir. We apply the algorithm to one of the major fractured reservoirs at Teapot Dome (Wyoming). We found that the critical fracture components of the reservoir such as those associated with the regional folding and cross-regional faulting are better defined by the new method. The example demonstrates the potential of the technology for more robust characterization of fractured reservoirs.

SEG Technical Program Expanded Abstracts 2015, 2015

Quantifying localized deformation in the target reservoir formations is of importance for the dri... more Quantifying localized deformation in the target reservoir formations is of importance for the drilling and production of hydrocarbons. Our recent efforts have been primarily focused on generating seismic geometric attributes (discontinuity, curvature, and flexure) and applying them for qualitative description of fractured reservoirs. This study presents a new method for quantitative strain analysis based on reflection geometry from 3D seismic data, and the generated tensor could help quantify both normal strain and shear strain of reservoir formations. We apply the method to one of the major fractured reservoirs at Teapot Dome (Wyoming) that is known to be caused by bending and shearing of the reservoir formation. The results not only help differentiate shear deformation from contractional and extensional ones, but also demonstrate a good correlation between producing wells and high-strain zones. The example indicates the potential of the technology for more robust and quantitative characterization of fractured reservoirs.

SEG Technical Program Expanded Abstracts 2016, 2016

Seismic texture analysis is a common and useful tool in delineating depositional features from th... more Seismic texture analysis is a common and useful tool in delineating depositional features from three-dimensional (3D) seismic surveys, and various texture attributes have been presented for robust facies interpretation, including the popular gray-level co-occurrence matrix (GLCM) and its derived attributes. When applied for attribute extraction from a seismic volume, most texture algorithms perform a gray-level transformation that rescales seismic amplitude into a user-defined range linearly. However, most features of interpretation interest in a seismic dataset often cover only a small portion of its whole amplitude range. For improved texture delineation of such features, they are expected to be represented by more gray levels while the rest by fewer levels, which is non-linear. This study proposes implementing three non-linear (logarithmic, exponential and sigmoid) transformations for seismic texture attribute extraction and interpretation. Applications to a deep marine depositional system from Angola demonstrates an improved resolution of GLCM homogeneity and contrast, which help better delineate channels and other features such as fans and lobes compared to the traditional linear transformation.

Fracture characterization is critical to reliable prediction of fractured reservoirs. Fractures f... more Fracture characterization is critical to reliable prediction of fractured reservoirs. Fractures formed by folding and/or shearing of reservoir formations, can be detected using seismic curvature and flexure analysis. Previous curvature and flexure analysis methods often have limitations in accuracy and efficiency in the presence of structural dip. We have developed new algorithms for volumetric curvature and flexure analysis based on 3D surface rotation using the local reflector dip to improve the accuracy and efficiency for curvature and flexure analysis in structurally complex settings. Among the various measures of curvature and flexure in 3D space, we have focused on signed maximum curvature and flexure that are considered to be most effective for predicting intensity and orientation of faults and fractures in fractured reservoirs. The application of the algorithms to a 3D seismic survey from Teapot Dome (Wyoming) demonstrated that the new methods help resolve subtle structural details that are otherwise not easily discernible from regular amplitude and conventional attributes, thus enhancing our capability to visualize and understand the structural complexity of fractured reservoirs.

Seismic flexure is a new geometric attribute with the potential of delineating subtle faults and ... more Seismic flexure is a new geometric attribute with the potential of delineating subtle faults and fractures from three-dimensional (3D) seismic surveys, especially those overlooked by the popular discontinuity and curvature attributes. Although the concept of flexure and its related algorithms have been published in the literature, the attribute has not been sufficiently applied to sub-surface fault detection and fracture characterization. This paper provides a comprehensive study of the flexure attribute, including its definition, computation, as well as geologic implications for evaluating the fundamental fracture properties that are essential to fracture characterization and network modeling in the subsurface, through applications to the fractured reservoir at Teapot Dome, Wyoming (USA). Specifically, flexure measures the third-order variation of the geometry of a seismic reflector and is dependent on the measuring direction in 3D space; among all possible directions, flexure is considered most useful when extracted perpendicular to the orientation of dominant deformation; and flexure offers new insights into qualitative/quantitative fracture characterization, with its magnitude indicating the intensity of faulting and fracturing, its azimuth defining the orientation of most-likely fracture trends, and its sign differentiating the sense of displacement of faults and fractures.

GEOPHYSICS, 2015

Fracture characterization is fundamental to the reliable prediction of fractured reservoirs; howe... more Fracture characterization is fundamental to the reliable prediction of fractured reservoirs; however, it is difficult and expensive to obtain detailed fracture information required for reservoir prediction due to the lack of direct observational data in the subsurface. Here we develop seismic analysis methods to characterize fractured reservoirs based on reflection geometry related to bending and shearing of reservoir formations. Among various geometric attributes, we focus on extreme curvature and extreme flexure that are considered effective at detecting fractures. Extreme curvature refers to the signed absolute maximum curvature at a specific azimuth where the curve shape is the tightest, whereas extreme flexure refers to the signed absolute maximum gradient of curvature at a specific azimuth where the curve shape changes the most. We implement new algorithms based on analytical equations to calculate extreme curvature and extreme flexure along with the corresponding azimuth from 3D seismic data. Results from 3D seismic surveys demonstrate that the new algorithms help resolve structural details that are otherwise not easily discernible from regular amplitude and conventional attributes. Most importantly, the algorithms hold the potential to volumetrically detect and visualize fractures in an automatic and quantitative manner. We conclude that extreme curvature and extreme flexure attributes have important geologic implications for predicting fundamental fracture properties that are critical to fractured reservoir characterization in the subsurface.

Computers & Geosciences, 2014

In 3D seismic interpretation, both curvature and curvature gradient are useful seismic attributes... more In 3D seismic interpretation, both curvature and curvature gradient are useful seismic attributes for structure characterization and fault detection in the subsurface. However, the existing algorithms are computationally intensive and limited by the lateral resolution for steeply-dipping formations. This study presents new and robust volume-based algorithms that evaluate both curvature and curvature gradient attributes more accurately and effectively. The algorithms first instantaneously fit a local surface to seismic data and then compute attributes using the spatial derivatives of the built surface. Specifically, the curvature algorithm constructs a quadratic surface by using a rectangle 9-node grid cell, whereas the curvature gradient algorithm builds a cubic surface by using a diamond 13-node grid cell. A dip-steering approach based on 3D complex seismic trace analysis is implemented to enhance the accuracy of surface construction and to reduce computational time. Applications to two 3D seismic surveys demonstrate the accuracy and efficiency of the new curvature and curvature gradient algorithms for characterizing faults and fractures in fractured reservoirs.

Geophysical Prospecting, 2015

Most positive/negative curvature and flexure are among the most useful seismic attributes for det... more Most positive/negative curvature and flexure are among the most useful seismic attributes for detecting faults and fractures in the subsurface based on the geometry of seismic reflections. When applied to fracture characterization and modelling of a fractured reservoir, their magnitude and azimuth help quantify both the intensity and orientation of fracturing, respectively. However, previous efforts focus on estimating only the magnitude of both attributes, whereas their associated azimuth is ignored in three-dimensional (3D) seismic interpretation. This study presents an efficient algorithm for simultaneously evaluating both the magnitude and azimuth of most positive/negative curvature and flexure from 3D seismic data. The approach implemented in this study is analytically more accurate and computationally more efficient compared with the existing approach. The added value of extracting most positive/negative curvature and flexure is demonstrated through the application to a fractured reservoir at Teapot Dome (Wyoming). First, the newly extracted attributes make computer-aided fault/fracture decomposition possible. This allows interpreters to focus on one particular component for fracture characterization at a time, so that a composite fractured reservoir could be partitioned into different components for detailed analysis. Second, curvature/flexure azimuth allows interpreters to plot fracture histogram and/or rose diagram in an automatic and quantitative manner. Compared with the conventional plotting rose diagram based on manual measurements, automatic plotting is more efficient and offers unbiased insights into fracture systems by illuminating the most likely orientations of natural fractures in fractured reservoirs.

Computers & Geosciences, 2014

In a 3D seismic survey, detecting seismic discontinuities is vital to robust structural and strat... more In a 3D seismic survey, detecting seismic discontinuities is vital to robust structural and stratigraphic analysis in the subsurface. Previous methods have difficulty highlighting subtle discontinuities from seismic data in cases where the local amplitude variation is of non-zero mean. This study proposes implementing a gray-level transformation and the Canny edge detector for improved imaging of discontinuities. Specifically, the new process transforms seismic signals to be of zero mean and helps amplify subtle discontinuities, leading to an enhanced visualization for structural and stratigraphic details. Applications to various 3D seismic datasets demonstrate that the new algorithm helps better define channels, faults, and fractures than the traditional similarity, amplitude gradient, and semblance attributes.

SEG Technical Program Expanded Abstracts 2014, 2014

Seismic curvature is a useful second-order geometric attribute and has demonstrated its value for... more Seismic curvature is a useful second-order geometric attribute and has demonstrated its value for structure analysis, especially for fracture characterization in fractured reservoirs. Our recent efforts have been primarily focused on computing most extreme (signed maximum) curvature, whose magnitude and direction are usually associated with and indicative of the most-likely intensity and orientation of fractures in 3D space, respectively. This study presents an applicable equation for computing curvature attribute along any direction in 3D space, and an analytical algorithm that can simultaneously calculate the magnitude and azimuthal direction of the most extreme curvature at any location in the reservoir. We apply the algorithm to one of the major fractured reservoirs at Teapot Dome (Wyoming). We found that the critical fracture components of the reservoir such as those associated with the regional folding and cross-regional faulting are better defined by the new method. The example demonstrates the potential of the technology for more robust characterization of fractured reservoirs.

SEG Technical Program Expanded Abstracts 2015, 2015

Quantifying localized deformation in the target reservoir formations is of importance for the dri... more Quantifying localized deformation in the target reservoir formations is of importance for the drilling and production of hydrocarbons. Our recent efforts have been primarily focused on generating seismic geometric attributes (discontinuity, curvature, and flexure) and applying them for qualitative description of fractured reservoirs. This study presents a new method for quantitative strain analysis based on reflection geometry from 3D seismic data, and the generated tensor could help quantify both normal strain and shear strain of reservoir formations. We apply the method to one of the major fractured reservoirs at Teapot Dome (Wyoming) that is known to be caused by bending and shearing of the reservoir formation. The results not only help differentiate shear deformation from contractional and extensional ones, but also demonstrate a good correlation between producing wells and high-strain zones. The example indicates the potential of the technology for more robust and quantitative characterization of fractured reservoirs.

SEG Technical Program Expanded Abstracts 2016, 2016

Seismic texture analysis is a common and useful tool in delineating depositional features from th... more Seismic texture analysis is a common and useful tool in delineating depositional features from three-dimensional (3D) seismic surveys, and various texture attributes have been presented for robust facies interpretation, including the popular gray-level co-occurrence matrix (GLCM) and its derived attributes. When applied for attribute extraction from a seismic volume, most texture algorithms perform a gray-level transformation that rescales seismic amplitude into a user-defined range linearly. However, most features of interpretation interest in a seismic dataset often cover only a small portion of its whole amplitude range. For improved texture delineation of such features, they are expected to be represented by more gray levels while the rest by fewer levels, which is non-linear. This study proposes implementing three non-linear (logarithmic, exponential and sigmoid) transformations for seismic texture attribute extraction and interpretation. Applications to a deep marine depositional system from Angola demonstrates an improved resolution of GLCM homogeneity and contrast, which help better delineate channels and other features such as fans and lobes compared to the traditional linear transformation.

Fracture characterization is critical to reliable prediction of fractured reservoirs. Fractures f... more Fracture characterization is critical to reliable prediction of fractured reservoirs. Fractures formed by folding and/or shearing of reservoir formations, can be detected using seismic curvature and flexure analysis. Previous curvature and flexure analysis methods often have limitations in accuracy and efficiency in the presence of structural dip. We have developed new algorithms for volumetric curvature and flexure analysis based on 3D surface rotation using the local reflector dip to improve the accuracy and efficiency for curvature and flexure analysis in structurally complex settings. Among the various measures of curvature and flexure in 3D space, we have focused on signed maximum curvature and flexure that are considered to be most effective for predicting intensity and orientation of faults and fractures in fractured reservoirs. The application of the algorithms to a 3D seismic survey from Teapot Dome (Wyoming) demonstrated that the new methods help resolve subtle structural details that are otherwise not easily discernible from regular amplitude and conventional attributes, thus enhancing our capability to visualize and understand the structural complexity of fractured reservoirs.

Seismic flexure is a new geometric attribute with the potential of delineating subtle faults and ... more Seismic flexure is a new geometric attribute with the potential of delineating subtle faults and fractures from three-dimensional (3D) seismic surveys, especially those overlooked by the popular discontinuity and curvature attributes. Although the concept of flexure and its related algorithms have been published in the literature, the attribute has not been sufficiently applied to sub-surface fault detection and fracture characterization. This paper provides a comprehensive study of the flexure attribute, including its definition, computation, as well as geologic implications for evaluating the fundamental fracture properties that are essential to fracture characterization and network modeling in the subsurface, through applications to the fractured reservoir at Teapot Dome, Wyoming (USA). Specifically, flexure measures the third-order variation of the geometry of a seismic reflector and is dependent on the measuring direction in 3D space; among all possible directions, flexure is considered most useful when extracted perpendicular to the orientation of dominant deformation; and flexure offers new insights into qualitative/quantitative fracture characterization, with its magnitude indicating the intensity of faulting and fracturing, its azimuth defining the orientation of most-likely fracture trends, and its sign differentiating the sense of displacement of faults and fractures.