# Simulation and experimental study of calcium sulfate and barium sulfate scale formation and Inhibition in petroleum engineering

## TL;DR

This study examines how calcium and barium sulfate scale forms in petroleum engineering and tests folic acid as an effective green inhibitor.

## Contribution

The study introduces folic acid as a novel, green inhibitor for sulfate scale with high efficiency compared to commercial alternatives.

## Key findings

- Folic acid reduced calcium and barium sulfate precipitation by 50.8% and 44.8% respectively.
- Folic acid mitigated calcium and barium deposition by 53.7% and 47.2% with dolomite rock.
- Commercial inhibitors were less effective than folic acid for sulfate deposition.

## Abstract

Petroleum engineering could engage numerous challenges caused by sulfate mineral precipitation and deposition. This severe critical issue which could directly lead to production reduction, was investigated in this study. Accordingly, the precipitation, deposition, and inhibition of calcium and barium sulfate were scrutinized from the simulation and experimental perspectives. The simulation tools, PHREEQC and Aspen Plus, were first used to corroborate the results of the high-temperature (90 °C) standard static experimental tests conducted for calcium and barium sulfate precipitation and deposition phenomena. In the experimental phase of the inhibition study, folic acid was evaluated as a green scale inhibitor (SI) and compared to a phosphonate-based commercial SI regarding inhibition efficiency (IE%) and inhibition mechanisms. The findings indicated that folic acid reduced calcium and barium sulfate precipitation as much as 50.8% and 44.8% respectively at the specific critical mixing ratios through the crystal modification inhibition mechanism provided by scanning electron microscopy (SEM) analysis. Moreover, folic acid could perform effectively in the mitigation of calcium and barium deposition by 53.7% and 47.2% in the presence of 5 g of dolomite rock. However, a comparison of a commercial SI and folic acid showed that the commercial SI was weaker than folic acid for mitigation of sulfate deposition through the threshold inhibition mechanism.