Objective The aim of this study is to improve the understanding upon the role of individual chemical on the production of oily sludge and provide a reference for the reduction and control of oily sludge in oil and gas field.

Methods The study was carried out to preliminarily identify the contribution rate of wastewater treatment chemicals in sludge and their production pattern. Furthermore, sludge production rates in 4 typical stations of Xinjiang Oilfield were estimated theoretically, and the dosages of wastewater treatment chemicals in Station A were optimized.

Results The study showed that wastewater treatment chemicals would produce a certain amount of sludge, of which the contribution rates of desiliconizing agent (47.95%) and water purifying agent(PAC) (20.00%-31.00%) were far greater than the contribution rate of flocculant (PAM)(3.00%-8.00%), which were the main sources of sludge contributed by wastewater treatment chemicals; The control variable method was subsequently adopted to optimize the dosage of various reagents. The recommended dosages for Station A were 250 mg/L of PAC and 10 mg/L of PAM.

Conclusions Considering the costs of wastewater treatment chemicals and their sludge yield, the quantitative analysis of the sludge yield of treatment chemicals for oil produced water could guide the optimization of chemicals selection.