P‐S survey design

Abstract

Fold, illumination, offset distribution and azimuth distribution were evaluated for PS survey design for two different projects. The first was planned to image an interval of interest from 380 m to 425 m depth, for the Paskapoo Formation, located in the Priddis area, near Calgary, Alberta. Orthogonal and slant geometries were tested with different parameters. Good results for the converted wave 3D design were found using a slant geometry design with receiver interval and source interval of 10 m, a receiver line interval of 50 m, a source line interval of 25 m and a maximum offset of 400 m. The slant geometry design gave better offset and azimuth distributions than the orthogonal geometry design. Illumination was similar in both types of geometries. Optimization of these parameters was reached by changing the receiver and source line intervals to 40 m, balancing quality requirements and cost related to the increase of number of shots when using 25 m as the source line interval. This design was done using CREWES QuadDes software. A second case study was undertaken where orthogonal and slant designs were tested for a project area with a deeper target, at 2160 m depth. Real situations were taken in to consideration such as moving source lines to pre‐existing cut lines and the effect of obstructions presented by lakes in the area of the survey. After the analysis, the orthogonal geometry design was chosen with 360 m source line interval, 240 m receiver line interval and 60 m source and receiver station intervals. The patch selected was 26 lines with 100 receivers per line to have an aspect ratio of about unity for optimum data inversion. This design was undertaken using OMNI software.