Varying GOR Effect on Oil Production for Nubian SANDSTONE using PIPESIM Software

Abstract

Evaluating the Gas-Oil Ratio (GOR) is crucial for optimizing oil recovery strategies, minimizing environmental impact, and ensuring economic viability. GOR represents a critical parameter in the oil and gas industry, as it deeply influences the complex relationships governing well production performance. A comprehensive evaluation of production system dynamics provides a data-driven framework to assess reservoir heterogeneity while analyzing and optimizing oil production relative to GOR. This study builds upon existing knowledge by evaluating the impact of varying GOR levels across four wells. A Black Oil model was developed and subsequently converted—using PVT data—into a Compositional Model to better understand fluid behavior, evaluate performance, improve production rates, and validate results against well-testing data. Comparative analysis between the Black Oil and Compositional models yielded additional insights into production enhancement strategies. Reservoirs with high GOR typically exhibit a gas cap that affects pressure distribution and fluid displacement, whereas low-GOR reservoirs present challenges related to fluid mobility and sweep efficiency due to the dominance of viscous forces. Results from Wells X1, X3, and X4 demonstrated a positive correlation between increases in tubing size, productivity index, and overall oil output. Upsizing the production tubing diameter significantly reduced flowing friction losses, thereby enabling higher volumetric flow rates, improving well deliverability, and maximizing potential oil production. Furthermore, adjusting the wellhead choke size proved pivotal in optimizing output; careful choke selection managed downhole pressure drops to maintain optimal conditions for enhanced fluid flow, where well X2 improved oil production rate by doubling when they applied a workover and increased the tubing size.