Joint OBN and 3D DAS VSP Data Acquisition and Processing in Offshore Abu Dhabi

Abstract

The world largest 3D DAS-VSP survey was completed through the joint OBN and 3D DAS-VSP data acquisition project. The data processing workflow includes deblending, noise removing, first break picking, FWI inversion, velocity modeling building and lease RTM processing. The multi-well 3D DAS-VSP data will be used to generate high-accuracy and high-resolution 3D structure image with a higher number of folds, and the attributes of the amplitude preserved imaging data can be used to identify fluid in the reservoir formation and tracing the reservoir layer distribution around the boreholes.The world largest 3D DAS-VSP survey through the joint OBN and 3D DAS-VSP data acquisition project;The data processing workflow includes deblending, noise removing, first break picking, VSP FWI to invert the velocity model and least-squares multiple RTM imaging processing. The world largest 3D DAS-VSP survey was completed through the joint OBN and 3D DAS-VSP data acquisition project. By using the airgun sources of an ongoing high-density OBN data acquisition project within the offshore of Abu Dhabi, the high-density OBN data and 3D DAS-VSP data were acquired simultaneously in a total of 13 wells. All the wells have armored optical cable preinstalled outside the production or injection tubing and the optical cable was strapped on the tubing with clampers at 10 m spacing. The data processing workflow includes deblending, noise removing, first break picking, VSP FWI to invert the velocity model and least-squares multiple RTM imaging processing. The multi-well 3D DAS-VSP data will be used to generate high-accuracy and high-resolution 3D structure image with a higher number of folds, and the attributes of the amplitude preserved imaging data can be used to identify fluid in the reservoir formation and tracing the reservoir layer distribution around the boreholes. DAS-VSP data can also been used to enhance borehole-driven 3D seismic data processing significantly. The DAS-VSP data can also be used for AVO analysis, reservoir fracture prediction, and anisotropy analysis and reservoir characterization. At the meantime, the armored optical cable is located near or inside the reservoir, the 3D DAS-VSP data will be used to extract formation average and interval velocity, deconvolution operator, absorption, attenuation (Q value), anisotropy parameters (η, δ, ε) as well as enhanced the OBN seismic data processing including velocity model calibration and modification, static correction, deconvolution, demultiple processing, high frequency restoration, anisotropic migration, and Q-migration.