Remote surveillance practices of surface displacements for Kazakhstan and Azerbaijan oil and gas fields and pipelines using multi-temporal radar satellite interferometry

Abstract

This paper focused on the applied remote surveillance practices of surface displacements for the subsidence and uplift risk assessments of the largest oil and gas fields and pipelines in Kazakhstan and Azerbaijan. In case of InSAR applications for Tengiz Oilfield in Kazakhstan, SBAS-InSAR remote sensing technique followed by 3D and 2D decompositions showed the continuous subsidence at the Tengiz oilfield with increasing velocity. 3D and 2D decompositions of LOS measurements to vertical movement showed that the Tengiz Oil Field 2018-2020 continuously subsided with the maximum annual vertical deformation velocity around 70 mm. The vertical deformation confirmed typical patterns of subsidence caused by oil extraction. However, detected east-west and north-south horizontal movements at the Tengiz field clearly indicated that the study area crossed by seismic faults is also affected by natural tectonic processes. In case of InSAR applications for pipelines, both PS-InSAR and SBAS-InSAR techniques showed continuous subsidence in the kilometer range of 13-70 crossing two seismic faults. The ground uplift deformations were observed in the pipeline kilometer range of 0-13. Although both PS-InSAR and SBAS measurements were highly consistent in deformation patterns and trends along pipelines, they showed differences in the spatial distribution of ground deformation classes and noisiness of produced results. SBAS showed better performance than PS-InSAR along buried petroleum and gas pipelines in the following aspects: the complete coverage of the measured points, significantly lower dispersion of the results, continuous and realistic measurements and higher accuracy of ground deformation rates against the GPS historical measurements. In case of InSAR applications for Absheron oil and gas fields, PS-InSAR showed the existence of ground deformation processes observed for the period of 2015-2017 with three hotspots of highest subsidence rates and three hotspots of highest uplift rates in oil and gas fields. The determined maximum displacement rates of subsidence and uplift processes were −26 mm/y and +23 mm/y, respectively. However spatial density analysis of deformation velocity presented the natural patterns of uplift and subsidence tectonic processes. This allowed to determine that two oil and gas fields hold a higher probability of being affected by man-made oil and gas exploration activities, whereas the one oil field is affected by both natural and man-made processes.