Workflow Considerations for Orthorhombic Imaging and Fracture Characterization
Orthorhombic velocity modeling and imaging are key factors in obtaining a full return on investment when using wide azimuth (WAZ) data. It is even more important in shale plays, where fracture/stress imaging is crucial for identifying the sweet spots that enable optimal drilling.
Orthorhombic parameter determination is challenging and requires proper handling of azimuthal data for imaging and characterization. In this presentation, the entire process of orthorhombic imaging and characterization is carried out in the Local Angle Domain (LAD), where parameters are measured in-situ over all reflection angles and azimuths. This contrasts with standard imaging solutions that operate on surface azimuth sectors or offset vector tiles (OVT) in the time and depth migrated domains, where approximations and assumptions compromise the solution.
In order to build an orthorhombic velocity model for imaging and fracture characterization, other workflow steps are essential to ensuring a more stable and reliable outcome. These processes are needed to solve problems routinely encountered in shale acquisitions. This presentation will also cover shallow velocity determination, denoising methods, and other processing steps that are pre-requisite to a successful orthorhombic imaging and characterization.
Shiv Singh is a geophysicist and, VP Geoscience Services. His main interests are the study and modeling of anisotropic velocity, including HTI/Orthorombic anisotropy for identification of fractures using P-wave seismic data and full azimuth image gathers, and AVA (Z) inversion for fracture mapping using full azimuth gathers. Prior to joining Paradigm/Emerson, Mr. Singh was Chief Geophysicist for ONGC, a State owned E&P Company in India, for more than 23 years. Mr. Singh holds a Master degree in Physics from Banaras Hindu University, Varanasi, India. He has published many papers on depth-velocity modeling and fracture characterization.