Abstract
Monitoring environmental hazards, owing to natural and anthropogenic causes, is an important issue, which requires proper data, models, and cross-validation of the results. The geodetic satellite missions, for example, the Gravity Recovery and Climate Experiment (GRACE) and Sentinel-1, are very useful in this respect. GRACE missions are dedicated to modeling the temporal variations of the Earth’s gravity field and mass transportation in the Earth’s surface, whereas Sentinel-1 collects synthetic aperture radar (SAR) data, which enables us to measure the ground movements accurately. Extraction of large volumes of water and oil decreases the reservoir pressure and form compaction and, consequently, land subsidence occurs, which can be analyzed by both GRACE and Sentinel-1 data. In this paper, large-scale groundwater storage (GWS) changes are studied using the GRACE monthly gravity field models together with different hydrological models over the major oil reservoirs in Sudan, that is, Heglig, Bamboo, Neem, Diffra, and Unity-area oil fields. Then, we correlate the results with the available oil wells production data for the period of 2003–2012. In addition, using the only freely available Sentinel-1 data, collected between November 2015 and April 2019, the ground surface deformation associated with this oil and water depletion is studied. Owing to the lack of terrestrial geodetic monitoring data in Sudan, the use of GRACE and Sentinel-1 satellite data is very valuable to monitor water and oil storage changes and their associated land subsidence over our region of interest. Our results show that there is a significant correlation between the GRACE-based GWS anomalies (ΔGWS) and extracted oil and water volumes. The trend of ΔGWS changes due to water and oil depletion ranged from –18.5 ± 6.3 to –6.2 ± 1.3 mm/year using the CSR GRACE monthly solutions and the best tested hydrological model in this study. Moreover, our Sentinel-1 SAR data analysis using the persistent scatterer interferometry (PSI) method shows a high rate of subsidence, that is, –24.5 ± 0.85, –23.8 ± 0.96, –14.2 ± 0.85, and –6 ± 0.88 mm/year over Heglig, Neem, Diffra, and Unity-area oil fields, respectively. The results of this study can help us to control the integrity and safety of operations and infrastructure in that region, as well as to study the groundwater/oil storage behavior.
Highlights
Assessment of surface mass changes is valuable for natural resources management, hazard preparedness, and food security
We firstly report our results of Gravity Recovery and Climate Experiment (GRACE) data analysis and the relation between the obtained ∆groundwater storage (GWS) and the oil production data, and we continue with persistent scatterer interferometry (PSI) results and the estimated land subsidence rate over the selected oil reservoirs owing to oil and water extraction
We utilized the GRACE monthly solutions processed by the Center for Space Research (CSR) throughout Jan 2003–Sep 2012 to estimate the rate of ∆total water storage (TWS) within the region of interest
Summary
Assessment of surface mass changes is valuable for natural resources management, hazard preparedness, and food security. Gravity Recovery and Climate Experiment (GRACE) data have great potential to estimate total water storage (TWS) and are used comprehensively to study hydrological processes [1,2] and groundwater storage (GWS) changes due to, for example, water depletion [2,3], permafrost thawing [4,5], and vertical land motion [6]. Land subsidence is generally caused by a various set of natural and human causes, for example, mining, extraction of liquids near the Earth surface (e.g., petroleum extraction), permafrost thawing, and seismic activities. In some cases, natural processes generate relatively slow vertical movements, for example, land uplift in Fennoscandia and Laurentia [6], where, on the contrary, subsidence due to human activities is relatively rapid [7]. Development of the time-series algorithms and its positive impact of reducing atmospheric artifacts [9,10] enhanced the contribution of the InSAR to land subsidence associated with groundwater depletion
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.