Method and system for detecting hydrocarbon reservoirs using amplitude-versus-offset analysis with improved measurement of background statistics

US6058074A · kind A · utility

Assignee

• Atlantic Richfield Company · US

Inventors

• Herbert W. Swan · Houston, US
• Bruce J. Verwest · Woking, GB

Key dates

• Filing date: Jul 31, 1998
• Grant date: May 2, 2000
• Expiry date: Jul 31, 2018

Classification

• Technology area (CPC G): Physics
• CPC primary: G01V2210/52
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A computer system and method of operating the same to apply overburden corrections to seismic signals prior to amplitude-versus-offset (AVO) analysis is disclosed. The system and method retrieve common midpoint gathers of the seismic signals, and generate analytical, or complex, AVO intercept and AVO slope traces therefrom, effectively stacking the traces in each gather. Over a sliding time window of the stacks, the computer system generates p-measure standard deviation and correlation statistics, preferably using a p-measure value less than one. The AVO intercept and AVO slope traces are then modified, at each depth point of interest corresponding to a time window placement, according to the relationship between the p-measure statistics and the desired statistics for the background distribution. Conformance of the background statistics to known values can be achieved, thus eliminating offset-dependent contamination of the AVO data; this is accomplished with minimal influence from AVO anomalous points, improving the sensitivity and accuracy with which petrophysically-interesting strata may be detected from AVO traces.