First Onshore DAS VSP in Abu Dhabi, A Complete Case Study, Onshore Abu Dhabi, UAE

Abstract ADNOC Onshore tested the distributed acoustic sensing (DAS) Vertical Seismic Profile (VSP) technique in a well in an Onshore field in order to gain confidence and knowledge for future commercial DAS VSP applications. The main VSP objective was to assess data quality for VSP imaging and velocity information. The VSP test ran prior to an injection startup test, allowing the effect of injection noise on active VSP records to be studied. A walkaway (multi-offset) VSP design and Zero-Offset VSP were selected. The operation required good communication within a diverse discipline project team. The VSP operation was under constant assessment throughout. A daily QC process was executed as planned: enabling field data to be checked, to ensure quality and confirm operation decisions. One of the main project risks was the uncertainty of data quality concerning fiber coupling to formations. In this case the fiber was deployed behind the tubing, and prior examination of casing cement bond logs showed fiber coupling to formations was not guaranteed over the full length of the well.