Adsorption and descaling of cellucotton and chitosan-modified bentonite for produced water

The compatibility of non-identical layers within the water present in the produced oil is poor and ion reactions in the oil mixed with water result in scale formation, thereby having a significant impact on oilfield safety production. In this study, methods for the descaling of produced water from different blocks were studied according to the quality characteristics of the produced water. Results show that scale was produced at a concentration of 94 mg/L when three-phase separated water and formation water were mixed at a volume ratio of 1:0.3. The flocculation performance was optimized when the pH of the mixed water sample was adjusted to 7.5 and addition amount of polyaluminium chloride and polyacrylamide was 80 and 3 mg/L, respectively. In addition, the mixed water sample was adsorbed and descaled using cellucotton and chitosan-modified bentonite. Results show that the method for treating the mixed water sample first with cellucotton followed by the chitosan-modified bentonite shows the optimal adsorption–flocculation performance, thereby reducing the concentration of scale in the treated water to 3 mg/L. © 2020 Tao Yu, Ying Wang, Chengtun Qu, Jinling Li and Bo Yang. This open access article is distributed under a Creative Commons Attribution (CC-BY) 3.0 license.