The concept of double blending: Combining incoherent shooting with incoherent sensing

Seismic surveys are designed so that the time interval between shots is sufficiently large to avoid temporal overlap between records. To economize on survey time, the current compromise is to keep the number of shots to an acceptable minimum. The result is a poorly sampled source domain. We propose to abandon the condition of nonoverlapping shot records to allow densely sampled, wide-azimuth source distributions (source blending). The rationale is that interpolation is much harder than separation. Source blending has significant implications for quality (source density) and economics (survey time). In addition to source blending, detector blending is introduced by which every channel records a superposition of detected signals, each with its own particular code. With detector blending, many more detectors can be used for the same number of recording channels. This is particularly beneficial when the number of detectors is very large (mass sensoring) or the number of channels is limited (wireless recording). The concept of double blending is defined as the case in which both source blending and detector blending are applied. Double blending allows a significant trace-compression factor during acquisition.