Development of Chemicals for the Treatment of Produced Fluids and Produced Water from Oilfields at High Water Cut Stage

At the later high water cut stage, expansion of industrialized chemical displacement technologies such as polymer flooding and ASP flooding has led to an increase in the amount of recycled water and slop oil accommodated by the surface production facilities. This has resulted in significant changes in the nature of the produced fluids and produced water, the treatment of which has become increasingly difficult. Through the analysis of key factors affecting produced fluid dehydration and produced water treatment, i.e. microfine oil droplets (particle size <4 μm), interfacial adsorption of nascent mineral particles (alkaline earth metal carbonate, ferrous sulfide and silicate flocs), and the shearing emulsification effect of centrifugal transfer pumps, it is concluded that the main causes affecting the stability of produced fluid and produced water are attributed to the “micronization” of dispersed phase and the “complexity” of impurity components. In response to this context, a series of new multifunctional chemicals, such as water stabilizers, multifunctional filter media detergents, and reverse demulsifiers with anti-scaling features have been developed with heightened and proven performance in produced fluid dehydration and associated water treatment following the application of such chemicals through field trials. Building upon these mechanistic insights and novel chemical developments, a systematic chemical dosing optimization system was established based on the principle of “mechanism-oriented, synergistic, system-regulated”. This has ultimately brought about highly efficient and cost-effective chemical solutions for the ground processing facilities of oilfields at the high water cut stage.