SkyGeo tracks subsidence and heave over producing fields all over the world. InSAR Monitoring gives you up to 100,000 measurement points per km², each with millimeter accuracy. For each measurement point, displacement over time is related to sub-surface effects of production. Reverse engineer this surface footprint to understand your reservoir.
Integration with geomechanical data and models
Production geologists, geophysicists and reservoir engineers all need to validate their subsurface models against a permanent backdrop of incomplete data. Pressure drop over time in a producing field can lead to reservoir compaction, movement of the overburden and subsidence of the surface above the reservoir. A particularly common effect in depleting fields is fault reactivation, induced by differential compaction between adjacent compartments. One fault compartment is more depleted than the other.
This compaction can be costly for production and for facilities above the ground. Fluid flow and compaction patterns in a reservoir will change over time. SkyGeo adds a dimension here, because subsurface mass transport leaves a dynamic footprint on the surface; you can track subsidence and uplift with unprecedented accuracy and completeness. The knowledge of these dynamics can support your model’s validation. InSAR Monitoring complements seismic profiles, and widely spaced data from surface tiltmeters to improve geophysical models.
The tightly spaced Belridge diatomite in California has historically seen high subsidence rates up to 30 cm / year. Our customer has optimised water-flooding strategy in this field. Injection in the high-porosity, low-permeability diatomite has notoriously unpredictable and dynamic effects. Our product provides continuous updates on subsidence and uplift with millimeter precision over the entire field. Insights in regional and local under-, or overshooting gets converted into continuous adjustments in injection flow rates with high granularity. The payback of this approach has been immediate in the form of reduced incidence of well-casing damage in the field.
InSAR applications for energy assets
Effective asset management means mitigating surface deformation and subsidence as it happens. This requires insight in surface dynamics regardless of daylight, cloud cover, weather and limits to safe access. The radar interferometry technology meets all these requirements and is widely accepted in geodetic applications. Since these deformation data are gathered by satellites and processed with our algorithm, we update our users’ deformation data automatically and periodically. For each asset’s specific requirements, we configure the radar satellite mission. We task data acquisition parameters on the satellite, (such as resolution, image size, wavelength and frequency of image acquisition) to best monitor our customers assets.
Installations and infrastructure
On the distance scale of installations for production, transportation, storage and processing, our products measure displacement in the infrastructure with a high degree of completeness. These insights into displacement dynamics will reveal for example high gradients in displacement rates, where high stresses likely affect the asset. These early indicators can inform further inspection. Our subsidence measurements have been validated with ground-based measurements in many different installations all over the world.
The first step in a site survey is usually to map the surface geology and active faults. Remote sensing plays a valuable role because these tasks can be accomplished without capital spend or ground crews. A remote fact-finding mission will establish if there is autonomous movement along fault zones, and if so, at which rates and in which direction. This yields immediate insights for new and mature fields. The surface survey will give a complete overview of the surface dynamic events underlying deformation. We can access historical satellite data as far back as 1992 enabling a long term perspective on geological forces at work.
Complement conventional data
Our products can be used to complement other data, such as (micro-)seismic mapping, downhole pressure gauging and tiltmeters. No capital expenditure is needed. In the case of horizontal drilling the mass displacement can follow unpredicted conduction pathways. Subsurface crack propagation and subsequent mass transport can be hard to predict or model. In both conventional and unconventional plays, local variations in stratigraphy and fault pattern can cause enough variation that model outcomes need continuous fine-tuning.
Any mapping based on satellite images – and deformation mapping in particular – is very information-dense: it typically yields several orders of magnitude more information than conventional terrestrial methods for surveying surface motion. The availability of all this new data of the earth’s surface motions also enables new, previously unimaginable applications. We make our maps with comparable accuracy, at a lower cost and no capital expenditure. The larger and the more inaccessible the area of interest, the higher the value added by remote sensing.
Surface measurements can help put quantitative constraints on geophysical models. Subsidence bowls tend to be symmetric even where the compaction in the payzone is not. Subsidence effects resulting from each compacting element are superposed, so subsidence bowls typically average out variations. Overburden anisotropy and slippage along fault patterns can affect the spread of subsidence. So vice versa, asymmetries in subsidence patterns combined with knowledge about overburden anisotropies or fault patterns can isolate “visible” compaction. The SkyGeo horizontal vs. vertical surface motion measurements can further improve compaction estimates thus constrained in the models.