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Scale precipitation modeling in the presence of scale inhibitors using MSE–SRK model

Baorui Zhang, Xiancun Zhang, Liping Zhang, Syed Imran Ali, and Syed Mohammad Tariq

Aktobe Munai Gas Field, China National Petroleum Corporation, Beijing, China

Received: 17 March 2025 Accepted: 19 July 2025

Abstract:

In this research study, scale precipitation modeling in the presence of a scale inhibitor is carried out using the mixed-solvent electrolyte (MSE)-Soave–Redlich–Kwong (SRK) model. The Scalechem software of OLI systems was used for the modeling purposes. The state-of-the-art MSE–SRK model incorporated water, oil, gas, and inhibitors simultaneously for the accurate modeling of scale precipitation. The combination of PVT (SRK model) and aqueous phase model (MSE) strengthens the scale prediction capabilities of software and eliminates or reduces the limitations of previous models which work only on aqueous phase models. The MSE–SRK model is particularly designed for petroleum industry sector to yield accurate results by considering all phases and species present in the system under varying operating conditions. The model predicted scale precipitation in the absence and presence of scale inhibitors at various locations of production system. The inhibition efficiency of six scale inhibitors namely; C₂H₈O₇P₂ (HEDP), C₃H₁₂NO₉P₃ (NTMP/ATMP), C₄₀H₄₀O₄₀ (PMA/PMLA), C₇H₁₁O₉P (PBTC), C₆H₂₀N₂O₁₂P₄ (EDTMP/EDTMPA), and C₉H₂₈N₃O₁₅P₅ (DTPMP) at a dosage of 5000 mg/L was determined. The outcomes suggest that the scaling potential of Pyrrhotite was observed to be the largest followed by Calcite, Aragonite, and Mackinawite. The precipitation potential of different scale deposits was found to increase considerably from the reservoir toward the separator. Contour plots were generated to assess the precipitation potential of various scales over a wide range of temperature and pressure conditions. The results revealed that the scaling tendency of Pyrrhotite was found to be high while for Mackinawite, Gypsum, Anhydrite and Siderite scales was found to be low at all conditions of temperature and pressure. For Calcite scales, their scaling tendency was found to be high at all temperature and pressure values except at higher pressure and lower temperature, at which it became moderate. For inhibition modeling results, excellent performance was exhibited by C₃H₁₂NO₉P₃ (NTMP/ATMP). Average performance was observed for inhibitor C₇H₁₁O₉P (PBTC). The inhibitors C₄₀H₄₀O₄₀ (PMA/PMLA), C₂H₈O₇P₂ (HEDP), C₉H₂₈N₃O₁₅P₅ (DTPMP), and C₆H₂₀N₂O₁₂P₄ (EDTMP/EDTMPA) yielded poor efficiency. This research study demonstrated a novel and robust workflow, offered by Scalechem software, for the accurate prediction of carbonate and sulfide scale based on the MSE–SRK model, taking into account all phases (water, gas, and oil) simultaneously, and its impact on chemical treatment program for the prevention of the scales problem.

Keywords: Scales; MSE–SRK model; Scale inhibitor; Modeling; Scalechem

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04264-5

Chemical Papers 79 (11) 7465–7481 (2025)