Produced Water Deoxygenation: Investigation of Nitrogen Purging scheme– Parametric Study – Part1

Abstract

Produced water (PW) is water that comes out of the well with the crude oil during crude oil production. The quality of produced water varies significantly based on the geochemistry of the producing formation, the type of hydrocarbon produced, and the characteristics of the producing well. A well-known obstacle hindering the re-use of the produced water, in different sectors, is the high content of dissolved oxygen (DO) as it can cause corrosion and polymer degradation. In this study, we report the experimental investigations for de-oxygenating samples of PW collected from Omani oil fields via a gas lift unpacked and packed column. Two types of packing (polyethylene rushing rings and spherical glass balls) were used. Upon treating the PW samples grafted with different concentration of polyacrylamide; 100-500 ppm, through different purging techniques at various N2 throughputs, a considerable reduction in the content of the dissolved oxygen (from saturation level to less than 1 ppm) was detected in the first duration (3 minutes). Upon examining purging durations up to 300 minutes, the DO removal efficiency was slightly improved; however, residues of DO (approaching 0.5 ppm) was left unremoved which indicates the necessity for elaborating another approach for treating the shallow DO levels.