Iron sulfide scale is considered a big issue in the oil and gas industry and a very common problem in daily operation bases. The iron scale severely affects the production rates and field operation, as the iron scale precipitation on the well completion tools or the pipelines` inner surfaces will decrease the diameter size and cause flow restriction. Failure of the downhole completions tools will decrease the well production and it might require workover operations to cure the problem. Such workover operations add an extra cost. In addition, the iron scale is a big problem for the petroleum reservoirs as it changes the rock wettability from water-wet to oil-wet. Many studies and researches were performed to find an economical and efficient removal for the iron sulfide scale. The main objective of this study is to find a new environmentally chemical solution to be used for iron sulfide scale removal. Additionally, to study the new fluid performance in terms of solubility for an iron scale (field sample), corrosion effect, and biodegradability for environmentally safe use.
Lab solubility tests had been done at different times and concentrations to get the optimum time and concentration that provides the optimum iron scale solubility rate. Corrosion tests were performed to determine the corrosion rates for the new chemical and the results were compared with other commercial chemicals for iron scale removal.
The results from the study showed excellent performance for the scale solubility and for the corrosion rates. The iron scale solubility showed 82 % after 6 hours at 125°C for the static condition. In addition, the solubility rates ranged from 77% after 2 hours to 81% after 24 hours along the 24 hours of different time steps. The corrosion rate is 0.04 lb/ft2 which is considered a small rate compared to other used commercial fluids. The research outcomes provide an efficient chemical for iron scale removal that is environmentally safe to be used in the oil and gas fields. The new environmentally friendly acid system NEFAS provides very good performance for iron scale removal, with a lower cost than commercial chemicals. Furthermore, the new system is a biodegradable and environmentally safe system.