A comparative experimental evaluation of the performance of additive compounds for inhibition of asphaltene precipitation from crude oil

ABSTRACT

In this work, the effects of four different chemical inhibitors, namely a polymeric surfactant, synthesized γ-Al₂O₃/NiO nanoparticles, epoxy resin, and canola oil to inhibit asphaltene precipitation in three different crude oils collected from various oil fields located in southern Iran. A high-pressure solid detection apparatus was employed to measure the onset point of asphaltene precipitation in crude oils with API ranging between 35 and 38 and various characteristics in the presence of the inhibitors in a wide range of concentrations ranging 0–20 wt. % at a high pressure of 2,000 psi and ambient temperature. The elemental composition of resin and asphaltene fractions in the crude oils was identified using a LEC elemental analyzer. The results showed that all fractions of precipitated asphaltenes were composed of low ratios of H (hydrogen)/C (carbon), which were an indication of large instability. Moreover, the screening experiments showed that the polymeric surfactant inhibitor with a base-nature was more efficacious with most oil samples due to the presence of high content (73%) of resin in this type of inhibitor. Besides, they can be used as a well-candidate for other oils not assessed in this work due to their high polarity and also compatibility with the structure of studied asphaltenes. It was found that the polymeric surfactant γ-Al₂O₃/NiO nanoparticles had the highest inhibition performance in comparison with the epoxy resin and canola oil.

KEYWORDS:

• Asphaltene
• crude oil
• inhibition efficiency
• inhibitor
• nanoparticles
• onset concentration
• precipitation

Acknowledgments

This research was undertaken with the assistance of laboratory services provided at the Research Institute of Petroleum Industry. We thank the laboratory staff for assisting in experiments.

Nomenclature

w_asph,prec Weight fraction of precipated asphaltene (wt. %)

η_inhibition Inhibition efficiency (%)

m_asph,ins Masses of insoluble asphaltene (kg)

m_asph,sol Masses of soluble asphaltene (kg)

CII Colloidal instability index

m_asph Mass of asphaltene (kg)

m_satu Mass of saturate (kg)

m_resn Mass of resin (kg)

m_armc Mass of aromatic (kg)

M_W Molecular weight (g/mol)

ρ Density (kg/m³)

BP Boiling point (K)

AOC Asphaltene onset concentration (cc)

Additional information

Notes on contributors

Shahin Alizadeh

Shahin Alizadeh is an MSc student in Petroleum Engineering, Tarbiat Modares University. He has a BSc in Petroleum Engineering from Shiraz University (2017). He is working on Asphaltene problems and enhanced oil recovery.

Fariborz Fazelipour

Fariborz Fazelipour was awarded a BSc in Petroleum Engineering (2018) from Shiraz University and an MSc in Petroleum Engineering from Tarbiat Modares University in 2021. His research interests include Thermodynamic modeling, enhance & improve oil recovery, and asphaltene problems.

Seyedeh Maryam Mousavi

Seyedeh Maryam Mousavi is a doctoral candidate in Chemical Engineering, Shiraz University. She has an MSc in Chemical Engineering from Yasouj University (2018) and a B.Sc in Chemical Engineering from Shahid Bahonar University of Kerman (2014). She is working on Asphaltene problems and synthesizing advanced nanomaterials.

Reza Mansourian

Reza Mansourian is an MSc student in Petroleum Engineering, Shiraz University. He was awarded a BSc in Petroleum Engineering (2018) from Shiraz University. His research interests include the enhance & improve oil recovery, asphaltene and wax problems, Molecular Dynamics, and Nanotechnology.

Jafar Qajar

Jafar Qajar is an assistant professor at the School of Chemical and Petroleum Engineering, Shiraz University. His work has focused on the study of the structure and properties of real porous materials via 2D/3D imaging techniques and digital rock physics as well as flow and transport in subsurface formations. Qajar holds an MSc degree in chemical engineering from Shiraz University, Iran, and a PhD degree in petroleum engineering from the University of New South Wales, Australia.