Natural Fracture Prediction: A Multiscale Integration of Seismic Data, Image Logs and Numerical Forward Modelling

Author(s):  
Q. Boersma ◽  
W. Athmer ◽  
M. Etchebes ◽  
J. Haukås ◽  
G. Bertotti
2021 ◽  
Author(s):  
M. Risyad ◽  
M. Muhtar ◽  
L. Xueying ◽  
A.S. Setiawan ◽  
M. Alam ◽  
...  

2021 ◽  
pp. 1-50
Author(s):  
Yongchae Cho

The prediction of natural fracture networks and their geomechanical properties remains a challenge for unconventional reservoir characterization. Since natural fractures are highly heterogeneous and sub-seismic scale, integrating petrophysical data (i.e., cores, well logs) with seismic data is important for building a reliable natural fracture model. Therefore, I introduce an integrated and stochastic approach for discrete fracture network modeling with field data demonstration. In the proposed method, I first perform a seismic attribute analysis to highlight the discontinuity in the seismic data. Then, I extrapolate the well log data which includes localized but high-confidence information. By using the fracture intensity model including both seismic and well logs, I build the final natural fracture model which can be used as a background model for the subsequent geomechanical analysis such as simulation of hydraulic fractures propagation. As a result, the proposed workflow combining multiscale data in a stochastic approach constructs a reliable natural fracture model. I validate the constructed fracture distribution by its good agreement with the well log data.


2007 ◽  
Vol 26 (9) ◽  
pp. 1154-1160 ◽  
Author(s):  
Simon Tod ◽  
Brian Taylor ◽  
Rodney Johnston ◽  
Tony Allen

2019 ◽  
Author(s):  
J.C. Menescal ◽  
Y. Bezerra ◽  
J.A. Souza ◽  
A. Hussein ◽  
R. Plateaux ◽  
...  

2019 ◽  
Vol 944 ◽  
pp. 1011-1019
Author(s):  
Yi Jin Zeng ◽  
Yan Xi ◽  
Shi Dong Ding ◽  
Jun Li ◽  
Xin Yu Hao ◽  
...  

Casing shear deformation, which is caused by fault slipping, is the main morphology of casing deformation occurred during multistage fracturing. In order to determine the relationship between fault slipping and casing shear deformation, the micro seismic data collected from engineering field which can reflect the reality of the formations was analyzed. A new numerical model was developed, and the influential factors on casing shear deformation were studied, including the fault slip distance of lower and upper interface, fault dip angle, the thickness of cement sheath and casing. The results of research shows that: (1) Fault is easily activated by fracturing, which was the main reason of casing shear deformation; (2) The greater the fault dip angel, the slip distance, the greater the casing shear deformation; (3) Increasing the wall thickness of casing or cement sheath is beneficial to decrease the degree of the shear deformation; (4) Two ways can be used to avoid and control the casing shear deformation, one is keeping the designed horizontal segment of well trajectory keep away from fracture-developed area, or be parallel to natural fracture, the other is using stage cementing technology. Research results can provide important reference for design and control of casing integrity during multistage fracturing in shale gas wells.


2019 ◽  
Vol 38 (2) ◽  
pp. 144-150 ◽  
Author(s):  
Marianne Rauch-Davies ◽  
David Langton ◽  
Michael Bradshaw ◽  
Allon Bartana ◽  
Dan Kosloff ◽  
...  

With readily available wide-azimuth, onshore, 3D seismic data, the search for attributes utilizing the azimuthal information is ongoing. Theoretically, in the presence of ordered fracturing, the seismic wavefront shape changes from spherical to nonspherical with the propagation velocity being faster parallel to the fracturing and slower perpendicular to the fracture direction. This concept has been adopted and is used to map fracture direction and density within unconventional reservoirs. More specifically, azimuthal variations in normal moveout velocity or migration velocity are often used to infer natural fracture orientation. Analyses of recent results have called into question whether azimuthal velocity linked to intrinsic azimuthal velocity variations can actually be detected from seismic data. By use of 3D orthorhombic anisotropic elastic simulation, we test whether fracture orientation and intensity can be detected from seismic data. We construct two subsurface models based on interpreted subsurface layer structure of the Anadarko Basin in Oklahoma. For the first model, the material parameters in the layers are constant vertically transverse isotropic (VTI) in all intervals. The second model was constructed the same way as the base model for all layers above the Woodford Shale Formation. For the shale layer, orthorhombic properties were introduced. In addition, a thicker wedge layer was added below the shale layer. Using the constructed model, synthetic seismic data were produced by means of 3D anisotropic elastic simulation resulting in two data sets: VTI and orthorhombic. The simulated data set was depth migrated using the VTI subsurface model. After migration, the residual moveouts on the migrated gathers were analyzed. The analysis of the depth-migrated model data indicates that for the typical layer thicknesses of the Woodford Shale layer in the Anadarko Basin, observed and modeled percentage of anisotropy and target depth, the effect of intrinsic anisotropy is too small to be detected in real seismic data.


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