Over the last 5 years, ACTeQ has gained considerable experience in dealing with complex, irregular survey geometries created by environmental and operational challenges and powerful emerging processing technologies such as Full Waveform Inversion (FWI) and Compressive Sensing (CS). The traditional metrics of minimum offset and fold are not adequate to assess the likely outcome of imaging workflows involving 5D interpolation. Mutual Coherence (MC) has addressed this challenge to some extent, but MC considers the source and receiver reconstructions independantly and can produce ambiguos results. 

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For these reasons, ACTeQ has developed a new survey design metric :-

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Adequately Constructed Time : ACT is the time at which adequate sampling of the Fresnel zone is achieved and 5D reconstruction is possible.

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The image shown below is taken from a project in Oman. This desert area is characterized by high, steep sand dunes. Exclusion zones were created to keep personnel and vehicles at a safe distance from high slope areas. Compressive sensing was used to minimize acquisition cost. The ACT map shown here demonstrates the impact of the irregular geometry on the ability to create a shallow image, and highlights areas where additional restricted source or receiver operations may be required.

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ACT is unambiguous and easy to interpret. ACTeQ believes that ACT is a useful metric allowing comparison of competing survey designs. ACTeQ is please to share all technical details. Please contact Dave Ridyard now for technical details of ACT or to discuss how ACT can be used on your next 3D project.