Utilizing near-field hydrophone data for high-resolution shallow hazard imaging

Abstract

Summary Shallow hazard imaging of the near surface is a key input to de-risk drilling plans. Exploration-style seismic acquisition inherits the limitations, for example, coarse temporal sampling, lack of small reflection angles, and low-frequency source. Therefore, additional measurements using dedicated high-resolution (HR) site surveys are required, at an extra cost and planning. However, potentially ultra-high-resolution measurements are also recorded in marine towed-streamer exploration-style acquisitions in the form of near-field hydrophone (NFH) measurements, located above the seismic sources. If the NFH recordings can be processed to remove the source signature and preserve the reflection energy, a broadband data set can be created at zero offset from the source with higher resolution in the shallow compared to conventional 3D marine seismic data. The challenges associated with creating such a workflow are: 1) being able to remove the source signature from all the NFH data sets and preserve signal, 2) producing a product that is as reliable and effective at imaging shallow hazards as a dedicated shallow hazard survey, and 3) being able to interpolate sparse crossline measurements. The workflow presented here showcases the solutions for these challenges and illustrates a comparison between the produced data with HR and ultra-HR dedicated images.