Edan Gofer

Schlumberger Limited | SLB

This study summarizes the efforts taken to provide reliable reservoir characterizations products to mitigate seismic interpretation challenges and delineation of the reservoirs. ADNOC has conducted seismic exploration activities to assess Miocene to Upper Cretaceous aged reservoirs in East Onshore Abu Dhabi. The Oligo-Miocene section comprises of i...

Knowledge of pore pressure, in-situ stress, and lithology in unconventional reservoirs is important for safe and economic drilling, hydrocarbon production, and geomechanics applications such as wellbore stability analysis and hydraulic fracturing. Reliable predrill predictions of pore pressure, in-situ stress, and lithology are thus required for sa...

A new data assimilation algorithm for joint litho-petroelastic (LPE) inversion using nonlinear anisotropic Zoeppritz reflectivity operators, together with iterative sequential filtering, is used to provide joint elastic, lithology, and petrophysical estimates. The sequential filtering approach is an attractive choice because integration of petroela...

Due to their low permeability, achieving economic production from unconventional reservoirs entails hydraulic fracturing to increase the surface area in contact with the reservoir. Important to the design of efficient hydraulic fractures is an understanding of pore pressure, the orientation and magnitude of principal stresses, the geomechanical pro...

Fractures in elastic media add compliance to a rock in the direction normal to the fracture strike. Therefore, elastic wave velocities in fractured rock will vary as a function of the energy propagation direction relative to the orientation of the aligned fracture set. Anisotropic Thomson‐Haskell matrix Rayleigh equations for a vertically transvers...

Optimization of production from unconventional reservoirs requires estimates of reservoir properties such as porosity, total organic carbon (TOC) content, clay content, fluid saturation, and fracture intensity. The porosity and TOC content help to determine reservoir quality, and the natural fracture intensity provides information important for the...

n unconsolidated granular media, the state of stress has a major effect on the elastic properties and wave velocities. Effective media modeling of granular packs shows that a vertically oriented uniaxial state of stress induces vertical transverse isotropy (VTI), characterized by five independent elastic parameters. The Rayleigh wave velocity is se...

In this paper, we present an amplitude variation with azimuth (AVAZ) non-linear orthorhombic inversion workflow. The workflow integrates an inversion based on linearized orthorhombic PP-reflectivity equations and an inversion based on non-linear general Zoeppritz equations. The former is suitable for weak contrasts and the latter valid also for str...

Orthotropic inversion uses azimuthally sectored seismic data stacked, based on incident angle ranges. Even for high-fold acquisition, this azimuth/angle grouping can result in low-fold angle stacks. Therefore, data processing techniques that ensure proper primary amplitude preservation, noise attenuation, and data alignment, are of paramount import...

Estimates of reservoir properties such as porosity, TOC content, clay content, fluid saturation, and fracture intensity are required for understanding unconventional reservoirs. The porosity and TOC content help to explain the reservoir quality; natural fracture intensity provides information important to the completion strategy. In this case study...

We suggest using rock physics based parameterization designed for granular media for surface wave inversion to estimate effective shear modulus of unconsolidated sediments at very low effective stress. The result is a very stable inversion scheme that yields a continuous profile of shear modulus vs. depth. We present a Bayesian approach to the surf...