Volume 2 - Issue 2, March - April 2026

This experimental study examines the viscosity reduction of Nigerian heavy crude oil, specifically Agbabu bitumen, through dilution with selected solvents including naphtha, n-heptane, phenol, toluene, and xylene. The influence of pressure variation on solubility-driven viscosity reduction was investigated. Solubility tests of bitumen in each solvent were conducted at pressures of 20, 80, 140, 200, and 260 psia. The results indicate that bitumen solubility increases with pressure for all solvents, with xylene exhibiting the highest solubility of 13.0 mol/dm³ at 260 psia. Kinematic and dynamic viscosities were measured using a Redwood viscometer at minimum and maximum solubility conditions. Xylene achieved the highest viscosity reduction, with dynamic viscosity decreasing from 390.6 cP to 13.95 cP and kinematic viscosity reducing from 420 cSt to 15.0 cSt. The study highlights the superiority of aromatic solvents for viscosity reduction of Agbabu bitumen, providing insights useful for heavy crude oil production and transportation. The discoveries of this study contribute to the development of cost-effective and efficient approaches for enhancing the production and transportation of heavy crude oil. The results also give valuable insights into the thermodynamic and rheological behavior of heavy oil- solvent mixtures under varying pressure conditions. This study's results can be applied to optimize the design and operation of heavy oil production and transportation systems, in the end improving the economic viability of heavy oil resources.

Adetokunbo FALADE, Temitope ONI, Diran OLANIYAN,"Experimental Study of Improving Nigerian Heavy Crude Oil (Agbabu Bitumen) Viscosity Reduction by Dilution with N-Heptane, Phenol, Toluene, Xylene, And Naphtha" International Journal of Advanced Multidisciplinary Research and Educational Development, V2(2): Page(873-883) Mar-Apr 2026. ISSN: 3107-6513. www.ijamred.com. Published by Scientific and Academic Research Publishing.