Schlumberger

Multimeasurement Streamer Technology

Multimeasurement streamer

IsoMetrix technology is enabled by a revolutionary streamer design that combines measurements of the total seismic pressure wavefield and its gradient—both vertically and crossline.

Traditional seismic streamers use hydrophones to measure scalar pressure. Spatial sampling along each streamer is generally good, and ranges from 12.5 m to as fine as 3.125 m. However, for operational and economic reasons, streamers are typically towed between 50 and 200 m apart, resulting in 16 to 64 times sparser sampling in the crossline direction. In complex geologies, this means that seismic energy propagating with a significant crossline element (i.e., across the streamer spread) may become aliased and create noise in image volumes subsequently used for structural and stratigraphic inversion. This increases risk in exploration, appraisal, development, and production activities.

IsoMetrix technology uses point-receiver technology and combines hydrophones with tri-axial microelectromechanical system (MEMS) accelerometers, which measure the full bandwidth particle acceleration due to the up- and down-going seismic wavefield. Measurements of particle acceleration are directly related to the gradient in the pressure wavefield. The multimeasurement streamer has an environmentally-responsible solid design with high rigidity, which increases robustness in harsh marine conditions.

Streamer noise mitigation

Particle motion sensors are extremely sensitive to acoustical vibrations within the cable itself. A critical consideration in the development of IsoMetrix technology was understanding the noise modes that propagate along the streamer; how they vary with the streamer construction and the dependency on sensor positioning. Dense single-sensor sampling of the accelerometers is the key enabler for accurately characterizing and then removing these noise modes, particularly at low frequencies. Powerful noise suppression has been shown to provide reliable signal from the accelerometers well below 10 Hz. For a typical spread of 12 streamers of 8-km length, over 500,000 active sensors are continuously recording for every shot record in a seismic survey, resulting in a step change in data volume to store and process efficiently.

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WesternGeco

Multimeasurement Streamer Technology for True Broadband Imaging

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