Avaz Analysis for Weak Azimuthal Anisotropy and Thin Layers - Case Study From the Lower Paleozoic Shale Play in Northern Poland
M. Cyz and M. Malinowski
Event name: 79th EAGE Conference and Exhibition 2017
Session: AVO - Case Studies
Publication date: 12 June 2017
Info: Extended abstract, PDF ( 1.2Mb )
Price: € 20
We present application of Amplitude versus Azimuth analysis (AVAz) for weak anisotropy (1-2 %) and thin layers (up to 25 m) case for Lower Paleozoic shale play in Northern Poland. Feasibility study using synthetic AVAz response indicated that we could expect detectable azimuthal signature given the expected low crack density only in the wet case (fluid-filled fractures), but luckily liquid phase is observed is studied area. We applied AVAz analysis on large, wide-azimuth 3D seismic survey after full-azimuth (non-sectored) pre-stack depth migration. AVAz results were then compared with volumetric seismic attributes giving correlation in major fault zones. Furthermore results were corroborated by available well data: XRMI image logs giving confirmation of acquired AVAz azimuths and by cross-dipole sonic logs confirming anisotropy level.