Oilfield treatment compositions contain water, hydrochloric acid and urea. The urea and water may be present at a urea/water weight ratio between 0.8 and 12.0, and the hydrochloric acid and urea may be present at a urea/hydrochloric acid molar ratio between 0.1 and 0.5. The compositions are present as one liquid phase. The volumes of the compositions are substantially higher than those of the water volumes; consequently, the amount of water necessary to perform various well-service operations is lower.