Extended Elastic Impedance (Penerapan Praktis)

by : ISH

1. Selayang Pandang

Metode yang pertamakali digunakan untuk inversi pada non-zero offset adalah Elastic Impedance (EI) yang diperkenalkan oleh Connolly,1999. Metode ini hanya bekerja pada sudut yang tidak lebih besar dari 30 derajat.

Oleh Whitcombe, 2002 menemukan bahwa dengan melebarkan sudut pada persamaan Shuey menjadi -90^o sampai dengan 90^o maka kita bisa mendapatkan informasi physical property dari batuan. Secara matematis ini bisa didapatkan dengan mengganti sin²(q) dengan c  pada persamaan two term Shuey:

(Artikel lengkap beserta gambar dan persamaan dapat didownload di sini)

Pseudo 3D Processing

By : Andi Mannappiang

Pseudo 3D is a term used in the survey industry for 2D seismic lines shot at 25 to 50m spacing to obtain a much denser grid than the usual site survey grid of 100m intervals. However, in the past few years, the OgeoSeis seismic processing team has developed the CUBE Method that can innovatively convert 2D seismic lines shot with 50 to 500m spacings into 3D volumes.

A set of several 2D lines covering a site can be converted into a single 3D volume based on dip constraint trace or time slice lateral interpolation. The volumes can be built from stacked data or migrated sections. 3D cubes built from stacks are processed as 3D data with one pass 3D migration and other processing steps. While, cubes from migrated sections are converted and integrated into a 3D cube with their initial processing parameters. Among the benefits of 2D to 3D conversion are:

• Seismic 3D cube with 2D high resolution
• Natural 3D cube with time slice presentation
• Greater data density from 2D data
• Clear and detailed lateral geological continuity
• Reliable and accurate direct geohazards indicators
• True 3D migration from stacked 2D data
• Multiple added value to 2D survey data cost
• Integrate Pseudo 3D cubes with existing 3D volumes
• Enhance existing 3D volumes  resolution (especially    shallow intervals)