Quantifying Two-Dimensional Surface Displacements Using High-Resolution Cosmo-SkyMed, TerraSAR-X and Medium-Resolution Sentinel-1 SAR Interferometry: Case Study for the Tengiz Oilfield

Abstract

The present study was aimed at comparing vertical and horizontal surface displacements derived from the Cosmo-SkyMED, TerraSAR-X and Sentinel-1 satellite missions for the detection of oil extraction-induced subsidence in the Tengiz oilfield during 2018–2021. The vertical and horizontal surface displacements were derived using the 2D decomposition of line-of-sight measurements from three satellite missions. Since the TerraSAR-X mission was only available from an ascending track, it was successfully decomposed by combining it with the Cosmo-SkyMED descending track. Vertical displacement velocities derived from 2D Decomposition showed a good agreement in similar ground motion patterns and an average regression coefficient of 0.98. The maximum average vertical subsidence obtained from the three satellite missions was observed to be −57 mm/year. Higher variations and deviations were observed for horizontal displacement velocities in terms of similar ground motion patterns and an average regression coefficient of 0.80. Fifteen wells and three facilities were observed to be located within the subsidence range between −55.6 mm/year and −42 mm/year. The spatial analyses in the present studies allowed us to suspect that the subsidence processes occurring in the Tengiz oilfield are controlled not solely by oil production activities since it was clearly observed from the detected horizontal movements. The natural tectonic factors related to two seismic faults crossing the oilfield, and terrain characteristics forming water flow towards the detected subsidence hotspot, should also be considered as ground deformation accelerating factors. The novelty of the present research for Kazakhstan’s Tengiz oilfield is based on the cross-validation of vertical and horizontal surface displacement measurements derived from three radar satellite missions, 2D Decomposition of Cosmo-SkyMED descending and TerraSAR-X ascending line-of-sight measurements and spatial analysis of man-made and natural factors triggering subsidence processes.

Surface Displacement Evaluation of Canto Do Amaro Onshore Oil Field, Brazil, Using Persistent Scatterer Interferometry (PSI) and Sentinel-1 Data

“…Furthermore, the mean velocity per grid reveals deformation rates ranging from −8.61 mm/year to 9.40 mm/year if quadrants with noisy points (areas near water resources) are eliminated. This deformation rate shows be lower when compared to deformational findings from other studies conducted in oil fields areas [3,43,44].…”

Remote Surveillance of Differential Deformation for Kazakhstan Offshore Kashagan Oilfield Using Microwave Satellite Remote Sensing

“…The multi-temporal coherence of the PS-InSAR measurements derived from SNT1 was higher than from CSK. Higher temporal decorrelation of X-band CSK images in comparison to C-band SNT1 was also reported by Bayramov et al [33] and Morishita et al [54]. According to Morishita et al [54], one of the reasons why the coherence for the C-band is higher than the X-band is the lower resolution of the C-band.…”

“…Therefore, it was not possible to relate detected subsidence hotspots to any kind of seismic processes. Additionally, recent studies by Bayramov et al [33] showed that the closest Tengiz oilfield at the coast of the Caspian Sea was subsiding because of man-made oil extraction and injection activities rather than seismicity. Based on the map of the Caspian Sea faults adapted from Levin et al [34], it was possible to observe that the Kashagan Field is located near a fault that might be subject to possible future activations either because of tectonic and seismic processes or man-made extraction of oil and gas resources (Figure 2h).…”

“…The characteristics of both satellite missions are presented in Table 1. VV and HH polarizations of SNT1 and CSK, respectively, were used due to the proven higher coherence of co-polarized acquisitions in the case of deformation monitoring applications [33,35]. SNT1 and CSK imagery were acquired from both descending (DSC) and ascending (ASC) tracks, allowing to derive differential vertical and horizontal deformation velocities and cumulative deformations using 2D decomposition of LOS measurements.…”

LADSDIn: LiCSAR-Based Anomaly Detector of Seismic Deformation in InSAR

“…Sentinel-1 acquires up to 2000 SAR images daily, with a data capacity of even 10 TB [19], [20]. In this context, more and more scholars are using MTInSAR technology and Sentienl-1 data to carry out high-precision seismic deformation studies [21], [22], [23]. Due to the extensive range of ground deformation information, good continuity, and high deformation accuracy obtained by MTInSAR technology, the results of fault geometry parameter inversion and sliding distribution inversion are more comprehensive, detailed, and reliable [24], [25].…”