Feasibility study on identifying wells with high sand production potential using the land subsidence maps (Case study: Alborz province)

Sand production is a process affecting the well performance significantly. It would make severe challenges to water depletion and pump operation. Due to high drilling costs, identifying the sand production phenomenon prior to locating a new well is highly important. Land subsidence would occur in areas with fine-grain aquifers as a consequence of high water depletion. Furthermore, the sand production phenomenon is also related to the fine-grain aquifer. First, the land subsidence was estimated in Alborz province using Sentinel-1 satellite images from 2017 to 2021. Then, the relationship between sand production and the land subsidence phenomenon was investigated using the existing field evidence in southern parts of Savojbolaq. Also, the information on some wells with sand production phenomenon was compared with land subsidence maps. Finally, the Jaccard coefficient was employed to identify the similarity between land subsidence and sand production maps. The results indicated that the maps were identical at the level of the Jaccard coefficient of 65%. In other words, the wells in the high-risk land subsidence area could suffer from the sand production phenomenon with a probability of 65%.