Development of composite hydrogel materials for cleaning the inner surface of pipelines

Abstract

Flexible, mechanically strong composite hydrogel materials based on polyacrylamide hydrogel (PAAH), clay minerals (kaolin, bentonite and montmorillonite), poly-N-vinylpyrrolidone (PVP) and SiO2 were developed for cleaning the inner surface of pipelines. The mechanical strength of composite hydrogels increases in the following order: PAAH-PVP > PAAH-Montmorillonite > PAAH-SiO2 > PAAH-Bentonite. The results showed that the composite hydrogel samples are able to sustain more than 200 cycles of vertical deformation without damage. The hydrogel «pigs» selected according to the values of tensile strength and Young's modulus were tested on model «small» and «big» pipelines. The application of hydrogel «pigs» for cleaning the model pipelines proved to be successful. In contrast to mechanical analogues, hydrogel «pigs» pass freely through the pipelines of various shape and size, ensure necessary hydraulic pressure in the inner surface, provide explosion and fire safety, and absorb water along in the course of movement inside the pipeline. Their cleaning efficiency of the model pipelines from the asphaltene-resin-paraffin deposits (ARPD) was evaluated as 93–95 %. The scaled up hydrogel «pigs» were fabricated for cleaning of oilfield pipes. The proposed materials would be of interest for oil transportation companies due to cost-efficiency and technological feasibility.