Marine Seismic Acquisition Techniques and Survey Design

Marine Seismic Acquisition

• Overview of course content and learning objectives
• Review of conventional marine seismic acquisition
• Wide-azimuth towed streamer seismic acquisition
• Seabed seismic acquisition
• Exercises on: CMP coverage, calculation of fold, matching offset & azimuth distribution to acquisition geometry. Class discussion on acquisition geometry attributes and survey design metrics

Learning objectives: Understand how conventional marine seismic acquisition techniques have developed over the last 10 years. Understand the limitations of conventional towed streamer seismic acquisition. Understand the economics and cost-benefit of new “advanced” marine seismic acquisition techniques. Appreciate the potential improvements in data quality and the interpretational benefits of the new techniques. Understand why, where and when the new techniques are applicable

Marine Seismic Acquisition

• Broadband acquisition
• Time lapse acquisition
• Simultaneous source acquisition
• Exercise on Ghost notch design
• Team survey design exercise: match 7 survey techniques to the description of their objectives, followed by team presentation of results and reasoning

Learning objectives: Understand how broadband data improves resolution. Understand the importance of low frequencies and how they can be obtained in the field. Understand the importance of repeatability and how it may be obtained in 4D acquisition. Understand how and when simultaneous source acquisition can be used to deliver improved data quality and/or more efficient operations

Survey Design

• Objectives and methods in survey design
• Building and earth model
• Resolution and sampling
• Survey design exercise: Students start working in teams on different survey designs to be presented on the final day

Learning objectives: Understand how the objectives of a new 3D survey are met by overcoming geophysical challenges. Understand the use of existing data in a survey design workflow. Understand what constitutes a viable earth model for 1D and 3D seismic modeling. Understand the different types of resolution in seismic data required for successful interpretation and reservoir characterization. Understand the sampling requirements in seismic acquisition for subsequent processing and interpretation of results.

Survey Design

• Modeling, using a 1D earth model, to determine offset/angle limits, muting, bin size, fold and migration aperture
• Designing a 3D acquisition geometry
• Seismic sources and modeling
• Modeling using a 3D earth model for sub-surface coverage
• 3D raytracing and wave-equation illumination modeling

Learning objectives: Understand how to determine the basic acquisition geometry using a few simple equations. Understand the choices and limitations of seismic source options. Recognize when subsurface complexity requires the use of 3D raytracing. Continue to work on survey design exercise.

Survey Design

• Logistics and efficiency in the field
• Choice of shooting area and shooting direction for survey duration and cost
• Finalization of survey design exercises
• Presentation of team survey designs
• Review of course objectives and feedback

Learning objectives: Understand how preferred survey design parameters need to be modified in the light of field logistics and environmental factors. Review course content and understand those acquisition parameters have a major impact on data quality and those that have a major impact on acquisition cost.