Influence of In-Situ Fuel Deposition on Air Injection and Combustion Processes

2007 ◽  
Vol 46 (04) ◽  
Author(s):  
G.D. Adagulu ◽  
I.Y. Akkutlu
Keyword(s):  
Air Injection ◽  
Combustion Processes ◽  
Fuel Deposition

Numerical Simulation of Combustion Tube Experiments and the Associated Kinetics of In-Situ Combustion Processes

1984 ◽  
Vol 24 (06) ◽  
pp. 657-666 ◽  
Author(s):  
C.Y. Lin ◽  
W.H. Chen ◽  
S.T. Lee ◽  
W.E. Culham
Keyword(s):  
Crude Oil ◽  
Combustion Front ◽  
Combustion Zone ◽  
Combustion Tube ◽  
Cracking Reaction ◽  
Oil Components ◽  
Combustion Processes ◽  
Kinetics Of ◽  
Fuel Deposition

Abstract This paper presents the results of numerical simulation of dry, forward combustion tube experiments. The kinetic aspects of in-situ combustion processes also are discussed. The goals of the study are to investigate processes also are discussed. The goals of the study are to investigate the fuel deposition mechanism and to identify the key parameters affecting the performance of in-situ combustion processes. The thermal simulator developed at Gulf R and D Co. was used in the study. It was modified to include the capillary outlet effects for a more realistic description of the oil and water productions. The following experimental data were matched: cumulative water and oil productions, position of the combustion front as a function of time, fuel consumption, position of the combustion front as a function of time, fuel consumption, temperature as a function of time and position, and the pressure drop across the tube. History matches were performed for two crude oils with distinctly different physical properties (gravities of 26.5 and 13 API [0. 896 and 0. 979 g/cm3]). The agreements between experimental data and simulation results were excellent. Results indicate that the component equilibrium K-values and the kinetics of cracking reactions are the most important parameters affecting the fuel deposition, and that the fuel deposition mechanism, the fuel composition, and the locations and sizes of the transient zones depend on the crude oil and reservoir rock properties. Simulation results are always sensitive to the K-values of the light oil component but insensitive to the K-values of the heavy oil component. Results are sensitive to the kinetics of cracking reaction only if the cracking reaction is catalytic or the peak temperature and the fuel consumption are sufficiently high. Furthermore, the fuel available may or may not be solely in the form of coke. Our study suggests that further investigations of the catalytic effect of reservoir rocks and reaction kinetics of the cracking reaction are needed. Also, more than two crude oil components may be required to simulate the evaporation effect of crude oil accurately. Introduction In in-situ combustion processes, many physical changes as well as chemical reactions take place simultaneously or sequentially in the vicinity of the combustion front. It is generally believed that the combustion zone is preceded by a cracking or superheated steam zone, where coke is formed and preceded by a cracking or superheated steam zone, where coke is formed and deposited on the sand grains, and some lighter crude oil components evaporate and move forward with the flowing gas phase. The kinetics of combustion and cracking reactions in the combustion zone and the cracking zone has been discussed widely in the literature. The mechanisms of the physical changes and chemical reactions occurring around the combustion zone can be studied effectively through numerical simulation by using a thermal simulator. Although a number of numerical simulations of combustion tube experiments have been performed with different thermal simulators, no conclusions regarding the mechanism of fuel deposition can be drawn from these studies. The mentioned simulations either neglect the formation of coke from cracking reaction or use a high cracking rate so that no residual oil will be present in the combustion zone. The mechanism of fuel deposition is controlled by two important processes: the evaporation of crude oil components and the kinetics of the processes: the evaporation of crude oil components and the kinetics of the cracking reaction. These two processes determine how much fuel eventually will be burned and how much fuel will be in the form of coke. It has been reported, that low-temperature oxidation can have a significant effect on the fuel deposition and fuel characteristics. However, this reaction is important only when oxygen is available downstream of the combustion front. If oxygen is used completely in a combustion tube experiment, low-temperature oxidation will not play an important role in the fuel deposition mechanism. For a system with a high cracking reaction rate, it is likely that all of the crude oil in the cracking zone will be either evaporated or coked so that coke is the sole source of fuel. However, if the cracking rate is so low that only a portion of crude oil in the cracking zone is evaporated or coked, then some residual crude oil also will be burned in the combustion zone. This is supported strongly by the experimental data of Hildebrand who conducted a number of combustion tube experiments using clean, crushed Berea sandpacks with a variety of crude oils. SPEJ p. 657

The Effect of Water Injection on Sustained Combustion in a Porous Medium

1970 ◽  
Vol 10 (02) ◽  
pp. 145-163 ◽  
Author(s):  
H.L. Beckers ◽  
G.J. Harmsen
Keyword(s):  
Cross Section ◽  
Combustion Zone ◽  
Water Injection ◽  
Combustion Process ◽  
Physical Reality ◽  
Porous Matrix ◽  
Theoretical Description ◽  
Air Injection ◽  
Injection Ratio

Abstract This paper gives a theoretical description of the various semisteady states that may develop if in an in-situ combustion process water is injected together with the air. The investigation bas been restricted to cases of one-dimensional flow without heat losses, such as would occur in a narrow, perfectly insulated tube. perfectly insulated tube. Different types of behavior can be distinguished for specific ranges of the water/air injection ratio. At low values of this ratio the injected water evaporates before it reaches the combustion zone, while at high values it passes through the combustion zone without being completely evaporated, but without extinguishing combustion. At intermediate values and at sufficiently high fuel in which all water entering the combustion zone evaporates before leaving it. Formulas are presented that give the combustion zone velocity as a function of water/air injection ratio for each of the possible situations. Introduction In-situ combustion of part of the oil in an oil-bearing formation has become an established thermal-recovery technique, even though its economic prospects are limited by inherent technical drawbacks. The process has been extensively investigated both in the laboratory and in the field, while theoretical studies have also been made. The latter studies showed how performance was affected by various physical and chemical phenomena, such as conduction and convection of phenomena, such as conduction and convection of heat, reaction rate and phase changes. The degree of simplification determined whether these studies were of an analytical or a numerical nature. Recently an improvement of the process has been proposed. This modification involves the proposed. This modification involves the injection of water together with the air. The water serves to recuperate the heat stored in the burned-out sand, which would otherwise be wasted. This heat is now used to evaporate water. The steam thus formed condenses downstream of the combustion zone, where it displaces oil. At sufficiently high water-injection rates unevaporated water is bound to enter the combustion zone because more heat is required for complete evaporation than is available in the hot sand. Experiments showed that even under these conditions combustion is maintained. The improvement consists in a lower oxygen consumption per barrel of oil displaced and lower combustion-zone temperatures. This paper gives a theoretical description of this so-called wet-combustion process as described by Dietz and Weijdema. The prime object is to answer the basic question whether at any water/air injection ratio this process can be steady so that combustion does not die out. This objective justifies a number of assumptions that do not entirely correspond to physical reality, but that owe necessary for a physical reality, but that owe necessary for a tractable analytical treatment. This treatment is limited to the following idealized conditions.The process occurs in a perfectly insulated cylinder of unit cross-sectional area and infinite length.The Hudds are homogeneously distributed over the cross-section of the cylinder.Exchange of heat between the fluid phases and between fluids and matrix is instantaneous, so that in any cross-section the fluid phases are in equilibrium and the temperatures of fluids and porous matrix are the same. porous matrix are the same.Pressure chops over distances of interest are small compared with the pressure itself. (Pressure is taken to be constant.)Injection rates are constant, and a steady state has already been obtained. The second assumption implies that no segregation of liquid and gas occurs. Experimentally this might be achieved by using small-diameter tubes, where segregation is largely compensated by capillarity. SPEJ P. 145

4D-3C geomechanical study of in-situ bitumen recovery in NW Canada using Toe-to-Heel Air Injection

First Break ◽  
2012 ◽  
Vol 30 (1818) ◽  
Author(s):  
K. Wikel ◽  
R. Kendall ◽  
R. Bale ◽  
J. Grossman ◽  
K. DeMeersman
Keyword(s):  
Air Injection ◽  
Bitumen Recovery

Upscaling Kinetics for Field-Scale In-Situ-Combustion Simulation

2015 ◽  
Vol 18 (02) ◽  
pp. 158-170 ◽  
Author(s):  
Anna Nissen ◽  
Zhouyuan Zhu ◽  
Anthony Kovscek ◽  
Louis Castanier ◽  
Margot Gerritsen
Keyword(s):  
Laboratory Experiments ◽  
Two Dimensions ◽  
Work Flow ◽  
Arrhenius Kinetics ◽  
In Situ Combustion ◽  
Performance Improvements ◽  
Combustion Simulation ◽  
New Formulation ◽  
Combustion Processes

Summary We demonstrate the effectiveness of a non-Arrhenius kinetic upscaling approach for in-situ-combustion processes, first discussed by Kovscek et al. (2013). Arrhenius reaction terms are replaced with equivalent source terms that are determined by a work flow integrating both laboratory experiments and high-fidelity numerical simulations. The new formulation alleviates both stiffness and grid dependencies of the traditional Arrhenius approach. Consequently, the computational efficiency and robustness of simulations are improved significantly. In this paper, we thoroughly investigate the performance of the non-Arrhenius upscaling method compared with Arrhenius kinetics. We investigate robustness by considering grid effects and sensitivity to heterogeneity. Performance improvements of the new kinetic upscaling approach compared with traditional Arrhenius kinetics are demonstrated through numerical experiments in one and two dimensions for both homogeneous- and heterogeneous-permeability fields.

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