Uncertainty Analysis on In-Situ Combustion Simulations Using Experimental Design

Abstract

Experimental design is a widely used statistical method for understanding the factors that impact an information gathering exercise such as mechanistic simulations. It is used here to gain insight into flow and operating conditions that affect in-situ combustion. Specifically, experimental design was applied to understand in-situ combustion of very heavy oil using a commercial thermal simulator. The design parameters investigated were selected based on combustion laboratory results and literature. These included activation energies of the reaction schemes, oil saturation, air injection rate and pressure control at the producer. A full factorial design was used to create the parametric space considering interactions between the parameters. The degree to which the combustion peak temperature, pressure, combustion front speed, recovery efficiency and coke deposited changed was used to determine the most critical parameters. Results showed the activation energy of the coke deposition reaction had the greatest influence on the combustion process. For the 3-reaction pathway assumed for crude-oil combustion, a slight increase in this activation energy inhibited the combustion reactions. The injection pressure of the system was impacted significantly by the initial oil saturation while the speed at which the front propagated was shown to be primarily a function of the air injection rate. Results also showed that for a given initial oil saturation, a limiting air flux existed below which oil plugging of the linear system occured. Given successful ignition and propagation of the front, optimal recovery was obtained between initial oil saturations of 45-70%. We also observed interaction between the parameters. The effect of the activation energy of the combustion reaction on the recovery was strongly dependent on the amount of oil initially in place. Recovery decreased with increasing activation energy at lower initial saturations, but was independent of activation energy at greater initial saturations. In addition, the velocity profile showed different incremental oil recovery rates with different initial oil saturation.

13C Solid-State NMR Analysis of the Chemical Structure in Petroleum Coke during Idealized In Situ Combustion Conditions

“…Coke is formed during the combustion stage both in the low-temperature oxidation (LTO) and the high-temperature oxidation (HTO) reactions . The LTO reaction is significant because of its lower reaction temperature region than 380 °C from the combustion front; it has been considered as one of the main mechanisms for controlling fuel supply in the process of in situ combustion and has received much attention over the years. ,− In addition, the HTO reaction of coke is also considered to be the main stage of significant oxygen consumption, which also provides the main source of heat generation in oil displacement and facilitates the production of carbon monoxide, carbon dioxide, and water. , Thus, it is equally necessary to gain insights into the preparation and characterization of coke which is stimulated by HTO. It is known that the macromolecular structure and the activity of various organic functional groups of coke formed in crude oil at different oxidation temperatures determine the different reactions in the conversion process .…”

Investigation of an Improved Polymer Flooding Scheme by Compositionally-Tuned Slugs

“…Ghaderi et al [12] deployed a D-Optimal design to perform sensitivity analysis and optimization for CO 2 -WAG injection. Ogunbanwo and Kovscek [13] utilized a three-level design to explore multiple-parameter interactions in in-situ combustion. Bevillon and Mohagerani [14] used Latin Hypercube design to check sensitivities and quantify uncertainties in a miscible EOR project in the Middle East.…”

The Catalytic Effect of Clay on In-Situ Combustion Performance

“…In-situ combustion (ISC) is one of the most efficient thermal EOR methods yielding the highest oil displacement of around 95% oil in place (Sarathi, 1998). However, ISC is one of the most complicated thermal EOR methods due to the complex reactions that take place during the process (Hascakir and Kovcek, 2014, Gutierrez et al, 2009, and Mamora et al, 1993, Ogunbanwo et al, 2012. Since it is a promising thermal recovery method with maximum oil displacement potential among all EOR methods, the efforts on understanding ISC still continue.…”