Impact of wells reconstruction on their operational parameters

Abstract

Use of deep water-bearing horizons on an industrial scale is an expensive undertaking, mainly in the first phase of the project which is the well construction stage. Also, emergencies occur during the well operation, with the most frequent including yield reduction caused by the poor technical condition of the well. These frequently lead to the total decommissioning of the well, caused, for example, by backfill, filter damage or casing pipe damage. After conducting the proper diagnostics, a decision is most often made in such cases to reconstruct a well, and much less seldom to drill a new well hole. Reconstruction of water intake wells usually encompasses replacement of the entire filter column with the well filter damaged as a result of ageing. As new technologies and materials become available on the market, it is possible to use new generation filters in the well construction, with better technical parameters (in terms of strength, hydraulics and corrosion resistance). In many cases, it allows for maintaining or achieving similar operational parameters in the reconstructed well. The determination of resources for a reconstructed well should, however, take into account modified filtration conditions in the aquifer's zone adjacent to the filter because of the zone siltation during previous use of the well. The paper includes an evaluation of the impact of the reconstruction of two wells extracting water from the Lower Cretaceous level on improvement of their yields.