Principles and Applications of InSAR During Development of Onshore Fields

Abstract

InSAR stands for Interferometric Synthetic Aperture Radar and is a proven technique for measuring ground movements. Satellites record radar images of the earth with every orbit, and these images get combined to measure minute vertical and horizontal movements of the ground surface.

The minute changes of the ground surface (in the millimeter/month range) can be used to give direct insights into movement of fluids within reservoirs and also movements of fluids close to the surface. It is then the responsibility of the reservoir teams and the EHS groups to use the information to improve their understanding of flow within the reservoir and to mitigate what might end up as a surface breach unless fixed. When used correctly, InSAR can be used to fine-tune injection strategies to improve recovery efficiency and also to constrain 4D seismic models of the subsurface.

Examples include several giant oil fields in California (Belridge and Midway Sunset) where InSAR is being actively used to assess the efficiency of waterflooding and steamflooding as well as provide advance warning of fluids that have moved from the reservoirs towards the surface via behind-pipe channels or shear planes caused by reservoir compaction. In the Groningen field of the Netherlands we are using InSAR to understand how pressure depletion within the giant reservoir is causing the reactivation of deep-seated faults and generating earthquakes. In the downstream petroleum industry we will present examples of stability monitoring of surface infrastructure and pipelines. Here, stability is essential for integrity and safety. With knowledge of the surface deformation characteristics it becomes possible to design mitigating strategies and safeguards.

To-date, InSAR is a technology seldom used in the upstream petroleum industry even though it has been around since the early 1990s. Although there is a lot of number-crunching to get good end results, the raw data are freely available and non-proprietary. Interpretation costs per square mile are low and new updated images become available every week or so depending on the satellite selected. In the current cash-constrained financial environment InSAR is a low-cost way to monitor the health of producing reservoirs and indicate areas where there is an imbalance between withdrawal and injection that needs to be corrected. By providing advance warning of potential fluid breaches to the surface, InSAR applications become key to successful EHS work as well.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018