Numerical Simulation of Forced Imbibition Based on Centrifuge Experiment of Middle East Carbonate Reservoir Cores

Abstract

Capillary pressure plays a vital role in governing the fluid flow in the reservoir. Various experiments are used to determine the capillary pressure. Among them is the centrifuge method, which subjects a core to centrifugal forces that results in the movement of fluids in and out of the core due to their density differences. The data obtained from the experiment is usually refined to obtain the inlet saturation and capillary pressure using analytical approaches and then further enhanced using numerical simulation. Numerical methods can also be adjusted to account for various scenarios, such as heterogeneity and mixed wettability, making them very accurate. Conventional carbonate reservoirs of the Middle East pose challenges in simulation due to abnormal characteristics, including mixed-to-oil wettability and heterogeneity. Commercial software that simulate the centrifuge experiment have mathematical models that are fixed and built independently of core properties. This reduces their accuracy for the varying core properties exhibited by the Middle East carbonate reservoirs. They are also expensive to purchase and maintain.

Therefore, the objective of this research was to develop a model that can accurately simulate forced imbibition based on the centrifuge experiment. The model was tailored to suit the complex nature of carbonate reservoirs. An open-source software allowing for flexibility, MATLAB Reservoir Simulation Toolbox (MRST), was used in this study. The model was then verified against commercial software SENDRA. Finally, the model was validated against laboratory-measured data from Middle East carbonate reservoirs.

The results of the history matching conducted on laboratory data with verification against SENDRA bore promising results. Oil production plots were matched and capillary pressure plots showed positive outcomes. The cores were observed to have mixed-to-oil wet characteristics when observing the capillary pressure plots as well as the relative permeability graphs generated from the input data used during history matching.

This study provides an insight into modeling forced imbibition centrifuge experiments with the aim of providing a cheaper and open-source alternative to expensive and rigid commercial software for the simulation of forced imbibition involving the characteristics of the Middle East carbonate reservoir. With successful implementation, residual oil saturation will be characterized with certainty, which further helps in the planning and development of carbonate reservoirs in the Middle East region.

Date of Award	27 Dec 2023
Original language	American English
Supervisor	Emad Al Shalabi (Supervisor)