AUTHOR=Yuan Zhou , Liao Xinwei , Zhang Kuaile , Zhao Xiaoliang , Chu Hongyang , Zou Jiandong 

TITLE=Mathematical Characterization of Inorganic Salt Precipitation From the Reaction of CO2 With Formation Brine and Its Application

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 8 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2020.00141

DOI=10.3389/fenrg.2020.00141

ISSN=2296-598X

ABSTRACT=In the process of CO2 enhanced oil recovery (CO2-EOR), CO2interacts with formation brine containing high concentrations of scale-forming ions to produce inorganic salt precipitation, which blocks the rock pore throats, changes the characteristics of the reservoir and thereby reduces the oil recovery rate. In this study, a series of experiments on the static reaction of CO2-formation brine were conducted. The amounts of precipitation formed from the interaction of CO2-formation brine under various conditions were tested. Using the PHREEQC software, the mathematical characterisation formulas between the precipitation amount and various environmental factors (e.g. temperature, pressure difference, scale-forming ion concentration and pH) were established. On this basis, a numerical simulation model of CO2 flooding in a typical area of Oilfield C was established. The distribution of inorganic salt precipitation during continuous gas flooding was predicted, and the effect of inorganic salt precipitation on oilfield recovery was analysed.