Azimuthal amplitude variation with offset analysis of physical modeling data acquired over an azimuthally anisotropic medium

Abstract

We evaluated a quantitative amplitude analysis of 3D physical model reflection data acquired over an experimental phenolic layer that modeled a fractured medium with one set of vertical fractures. The phenolic layer was overlain by two isotropic layers, the uppermost being water, and the data acquisition was designed to avoid the interference of the primary and ghost events. The elastic stiffness coefficients and hence the anisotropy of the phenolic layer were known in advance from a previous traveltime analysis. The reflection amplitudes from the top of the phenolic layer required corrections to make them suitable for an amplitude study. In addition to the usual amplitude corrections applied to seismic field data, a directivity correction specific to the physical model transducers was applied. The corrected amplitudes along different azimuths showed a clear azimuthal variation caused by the phenolic layer and agreed with amplitudes predicted theoretically. An amplitude variation with angle and azimuth inversion was performed for horizontal transverse isotropy (HTI) parameters of the phenolic layer. We determined from the inversion results that from the azimuthally varying P-wave reflectivity response, it was possible to estimate HTI parameters that compared favorably to those obtained previously by a traveltime analysis. This result made it possible to compute the S-wave splitting parameter [Formula: see text] (historically determined from S-wave data and directly related to fracture density) from a quantitative analysis of the PP data.

Influence of upscaling on identification of reservoir fluid properties using seismic-scale elastic constants

“…Following the work of Duren 28 and Mahmoudian et al . 29 , directivity can be corrected by dividing measured amplitudes by the cosine of the angle between the wave propagation direction and the vertical direction. The propagation direction at the location of a transducer is called the emergence angle 21 .…”

Cable-free Seismic Acquisition System

“…최근 다중방위 (Mahmoudian et al, 2015;Swanston et al, 2011), 다성분 (Grechka et al, 2005;Sanchis and Elboth, 2014), 3D 탐사 (Gharibi et al, 2012;Jeong and Suh, 2006;Naghizadeh, 2015), 탄성파 모니 터링 (Kim et al, 2011;Stammeijer and Hatchell, 2014;Yin et al, 2015) 등 다양한 자료취득 기술요구와 산악지형, 삼각주 지역, 육상과 해상 경계지대 등 다양한 지형조건에서 적용할 수 있는 탄성파 탐사기술 수요가 증가하고 있다 (Lansley, 2013). 수진기와 수진기가 케이블로 연결되지 않는 독립된 수 진기를 사용하는 무선(Cable-free) 탄성파 탐사기술은 다양한 탐사기술과 다양한 지형조건에서 탐사측선 설계가 가능하고 또한 수진기 설치와 수거가 편리한 장점이 있다 (Freed, 2008).…”

Azimuthal elastic impedance-based Fourier coefficient variation with angle inversion for fracture weakness

“…Reflection amplitude is superior to seismic velocities in characterizing fractured reservoirs due to its higher vertical resolution and sensitivity to the properties of a reservoir (Far et al 2013). Much work has been done in deriving linear P-wave reflection coefficients in HTI media (Rüger 1998;Pšencík and Martins 2001;Shaw and Sen 2006;Chen et al 2014a;Pan et al 2018a) and directly characterizing fractured zones using azimuthal P-wave reflectivity data (Mallick et al 1998;Gray and Todorovic-Marinic 2004;Bachrach et al 2009;Mahmoudian et al 2015;Wang et al 2019).…”