Evolving Smart Model to Predict the Combustion Front Velocity for In Situ Combustion

2015 ◽  
Vol 3 (2) ◽  
pp. 128-135 ◽  
Author(s):  
Mohammad Ali Ahmadi ◽  
Mohammad Masoumi ◽  
Reza Askarinezhad
Keyword(s):  
Combustion Front ◽  
Front Velocity ◽  
In Situ Combustion

Fuel Formation and Conversion During In-Situ Combustion of Crude Oil

SPE Journal ◽  
2013 ◽  
Vol 18 (06) ◽  
pp. 1217-1228 ◽  
Author(s):  
Hascakir Berna ◽  
Cynthia M. Ross ◽  
Louis M. Castanier ◽  
Anthony R. Kovscek
Keyword(s):  
Oil Recovery ◽  
Photoelectron Spectroscopy ◽  
Combustion Front ◽  
Combustion Products ◽  
Combustion Tube ◽  
Cross Sectional ◽  
In Situ Combustion ◽  
X Ray ◽  
Study Results

Summary In-situ combustion (ISC) is a successful method with great potential for thermal enhanced oil recovery. Field applications of ISC are limited, however, because the process is complex and not well-understood. A significant open question for ISC is the formation of coke or "fuel" in correct quantities that is sufficiently reactive to sustain combustion. We study ISC from a laboratory perspective in 1 m long combustion tubes that allow the monitoring of the progress of the combustion front by use of X-ray computed tomography (CT) and temperature profiles. Two crude oils—12°API (986 kg/m3) and 9°API (1007 kg/m3)—are studied. Cross-sectional images of oil movement and banking in situ are obtained through the appropriate analysis of the spatially and temporally varying CT numbers. Combustion-tube runs are quenched before front breakthrough at the production end, thereby permitting a post-mortem analysis of combustion products and, in particular, the fuel (coke and coke-like residues) just downstream of the combustion front. Fuel is analyzed with both scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). XPS and SEM results are used to identify the shape, texture, and elemental composition of fuel in the X-ray CT images. The SEM and XPS results aid efforts to differentiate among combustion-tube results with significant and negligible amounts of clay minerals. Initial results indicate that clays increase the surface area of fuel deposits formed, and this aids combustion. In addition, comparisons are made of coke-like residues formed during experiments under an inert nitrogen atmosphere and from in-situ combustion. Study results contribute to an improved mechanistic understanding of ISC, fuel formation, and the role of mineral substrates in either aiding or impeding combustion. CT imaging permits inference of the width and movement of the fuel zone in situ.

An Experimental Investigation of In Situ Combustion in High Permeability Contrast Systems

2021 ◽  
pp. 1-13
Author(s):  
Melek Deniz Paker ◽  
Murat Cinar
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
Combustion Front ◽  
Fractured Reservoirs ◽  
Front Propagation ◽  
High Permeability ◽  
Vertical Orientation ◽  
In Situ Combustion ◽  
Horizontal Orientation

Abstract A significant portion of world oil reserves reside in naturally fractured reservoirs and a considerable amount of these resources includes heavy oil and bitumen. Thermal enhanced oil recovery methods (EOR) are mostly applied in heavy oil reservoirs to improve oil recovery. In situ combustion (/SC) is one of the thermal EOR methods that could be applicable in a variety of reservoirs. Unlike steam, heat is generated in situ due to the injection of air or oxygen enriched air into a reservoir. Energy is provided by multi-step reactions between oxygen and the fuel at particular temperatures underground. This method upgrades the oil in situ while the heaviest fraction of the oil is burned during the process. The application of /SC in fractured reservoirs is challenging since the injected air would flow through the fracture and a small portion of oil in the/near fracture would react with the injected air. Only a few researchers have studied /SC in fractured or high permeability contrast systems experimentally. For in situ combustion to be applied in fractured systems in an efficient way, the underlying mechanism needs to be understood. In this study, the major focus is permeability variation that is the most prominent feature of fractured systems. The effect of orientation and width of the region with higher permeability on the sustainability of front propagation are studied. The contrast in permeability was experimentally simulated with sand of different particle size. These higher permeability regions are analogous to fractures within a naturally fractured rock. Several /SC tests with sand-pack were carried out to obtain a better understanding of the effect of horizontal vertical, and combined (both vertical and horizontal) orientation of the high permeability region with respect to airflow to investigate the conditions that are required for a self-sustained front propagation and to understand the fundamental behavior. Within the experimental conditions of the study, the test results showed that combustion front propagated faster in the higher permeability region. In addition, horizontal orientation almost had no effect on the sustainability of the front; however, it affected oxygen consumption, temperature, and velocity of the front. On the contrary, the vertical orientation of the higher permeability region had a profound effect on the sustainability of the combustion front. The combustion behavior was poorer for the tests with vertical orientation, yet the produced oil AP/ gravity was higher. Based on the experimental results a mechanism has been proposed to explain the behavior of combustion front in systems with high permeability contrast.

Reverse Combustion Instabilities in Tar Sands and Coal

1980 ◽  
Vol 20 (04) ◽  
pp. 267-277 ◽  
Author(s):  
Robert D. Gunn ◽  
William B. Krantz
Keyword(s):  
Reaction Zone ◽  
Combustion Front ◽  
Stability Theory ◽  
Coal Gasification ◽  
Gas Production ◽  
Volatile Components ◽  
In Situ Combustion ◽  
Tar Sands ◽  
Vertical Well

Abstract A linear stability analysis shows that reverse combustion in coal and tar sands is only conditionally stable for mobility ratios less than one. However, high air-flow rates and gas generation at the combustion front can be stabilizing influences. For unstable operation, an estimate of the size of the reverse combustion channel may be obtained from the curve for the most highly amplified wave length. This provides a method for calculating the air flux, combustion front velocity, and rate of progress of the burn front. Recently the U.S. DOE Laramie Energy Technology Center (LETC) and Sandia Laboratories obtained experimental data about reverse combustion from a field test of in-situ coal gasification at Hanna, WY. These data show that 9.7 days were required for the development of a reverse combustion path 68 to 70 ft in length. The stability theory developed in this work predicts a length of 64 ft for this same 9.7-day period. In addition to quantitative predictions, stability theory provides an explanation of certain puzzling qualitative observations concerning reverse combustion. Introduction In-situ combustion is a potentially useful method for recovering fossil fuels from underground deposits. A number of in-situ combustion field tests have been conducted in oil reservoirs, tar sands, oil shale deposits, and coal seams. In-situ combustion can be classified into two broad categories: reverse combustion, in which the reaction front travels countercurrent to the flow of air, and forward combustion, in which the reaction zone travels in the same direction as the flow of air. Reverse combustion is especially important for coal and tar sands. During forward combustion, tars vaporized at the flame front in either coal or tar sands travel by convection into cooler regions ahead of the reaction zone where they condense and subsequently reduce the natural permeability of the fuel bed. In reverse combustion, vaporized tars or other high-molecular-weight compounds generated in the reaction zone travel toward the production well through a heated area already contacted by the high temperatures of the combustion front. As an added advantage, reverse combustion in tar sands substantially increases the relative permeability to gas. In lignite and subbituminous coal, drying and partial combustion typically increase the effective permeability to gas by four orders of magnitude. However, bituminous coal frequently swells on heating, and the net effect of reverse combustion on the permeability of swelling coals has not been investigated thoroughly. In coal and tar sands, reverse combustion is primarily a coking or carbonization process - i.e., the volatile components of the tar or coal are partially combusted while most of the carbon or coke is left unburned. For these reasons, reverse combustion represents an important part of some in-situ combustion methods currently being investigated for tar sands and coal. In the linked vertical well process for in-situ coal gasification, reverse combustion is used first to develop a high-permeability path between the production and air injection wells, while in the second stage of the process forward gasification or combustion is used as the major gas production method. Both industrial companies and government laboratories have investigated the linked vertical well process. For tar sands, the LETC is considering the use of reverse combustion as a preparatory mechanism similar to that used in coal.

Kinetics of Wet In-Situ Combustion: A Review of Kinetic Models

2014 ◽  
Author(s):  
E. A. Cavanzo ◽  
S. F. Muñoz ◽  
A.. Ordoñez ◽  
H.. Bottia
Keyword(s):  
Kinetic Model ◽  
Crude Oil ◽  
Kinetic Models ◽  
Combustion Front ◽  
Chemical Interaction ◽  
Combustion Process ◽  
Oxidation Reactions ◽  
In Situ Combustion ◽  
Temperature Oxidation

Abstract In Situ Combustion is an enhanced oil recovery method which consists on injecting air to the reservoir, generating a series of oxidation reactions at different temperature ranges by chemical interaction between oil and oxygen, the high temperature oxidation reactions are highly exothermic; the oxygen reacts with a coke like material formed by thermal cracking, they are responsible of generating the heat necessary to sustain and propagate the combustion front, sweeping the heavy oil and upgrading it due to the high temperatures. Wet in situ combustion is variant of the process, in which water is injected simultaneously or alternated with air, taking advantage of its high heat capacity, so the steam can transport heat more efficiently forward the combustion front due to the latent heat of vaporization. A representative model of the in situ combustion process is constituted by a static model, a dynamic model and a kinetic model. The kinetic model represents the oxidative behavior and the compositional changes of the crude oil; it is integrated by the most representative reactions of the process and the corresponding kinetic parameters of each reaction. Frequently, the kinetic model for a dry combustion process has Low Temperature Oxidation reactions (LTO), thermal cracking reactions and the combustion reaction. For the case of wet combustion, additional aquathermolysis reactions take place. This article presents a full review of the kinetic models of the wet in situ combustion process taking into account aquathermolysis reactions. These are hydrogen addition reactions due to the chemical interaction between crude oil and steam. The mechanism begins with desulphurization reactions and subsequent decarboxylation reactions, which are responsible of carbon monoxide production, which reacts with steam producing carbon dioxide and hydrogen; this is the water and gas shift reaction. Finally, during hydrocracking and hydrodesulphurization reactions, hydrogen sulfide is generated and the crude oil is upgraded. An additional upgrading mechanism during the wet in situ combustion process can be explained by the aquathermolysis theory, also hydrogen sulphide and hydrogen production can be estimated by a suitable kinetic model that takes into account the most representative reactions involved during the combustion process.

Predictability of Crude Oil In-Situ Combustion by the Isoconversional Kinetic Approach

SPE Journal ◽  
2011 ◽  
Vol 16 (03) ◽  
pp. 537-547 ◽  
Author(s):  
Murat Cinar ◽  
Berna Hasçakir ◽  
Louis M. Castanier ◽  
Anthony R. Kovscek
Keyword(s):  
Crude Oil ◽  
Combustion Front ◽  
Front Propagation ◽  
Combustion Tube ◽  
Complex Nature ◽  
Oil Viscosity ◽  
In Situ Combustion ◽  
Temperature Oxidation ◽  
Isoconversional Analysis

Summary One method to access unconventional heavy-crude-oil resources as well as residual oil after conventional recovery operations is to apply in-situ combustion (ISC) enhanced oil recovery. ISC oxidizes in place a small fraction of the hydrocarbon, thereby providing heat to reduce oil viscosity and increase reservoir pressure. Both effects serve to enhance recovery. The complex nature of petroleum as a multicomponent mixture and the multistep character of combustion reactions substantially complicate analysis of crude-oil oxidation and the identification of settings where ISC could be successful. In this study, isoconversional analysis of ramped temperature-oxidation (RTO) kinetic data was applied to eight different crude-oil samples. In addition, combustion-tube runs that explore ignition and combustion-front propagation were carried out. By using experimentally determined combustion kinetics of eight crude-oil samples along with combustion-tube results, we show that isoconversional analysis of RTO data is useful to predict combustion-front propagation. Isoconversional analysis also provides new insight into the nature of the reactions occurring during ISC. Additionally, five of the 10 crude-oil/rock systems studied employed a carbonate rock. No system displayed excessive oxygen consumption resulting from carbonate decomposition at combustion temperatures. This result is encouraging as it contributes to widening of the applicability of ISC.

Experimental and Numerical Analysis of In-Situ Combustion in a Fractured Core

SPE Journal ◽  
2011 ◽  
Vol 16 (02) ◽  
pp. 358-373 ◽  
Author(s):  
H.. Fadaei ◽  
L.. Castanier ◽  
A.M.. M. Kamp ◽  
G.. Debenest ◽  
M.. Quintard ◽  
...  
Keyword(s):  
Combustion Front ◽  
Fractured Reservoirs ◽  
Experimental Studies ◽  
Steam Injection ◽  
Combustion Tube ◽  
Fractured Reservoir ◽  
In Situ Combustion ◽  
Matrix Permeability ◽  
The Matrix

Summary Approximately one-third of global heavy-oil resources can be found in fractured reservoirs. In spite of its strategic importance, recovery of heavy crudes from fractured reservoirs has found few applications because of the complexity of such reservoirs. In-situ combustion (ISC) is a candidate process for such reservoirs, especially for those where steam injection is not feasible. Experimental studies reported in the literature on this topic mentioned a cone-shaped combustion front, indicating that the process was governed by diffusion of oxygen into the matrix. The main oil-production mechanisms were found to be thermal expansion of oil and evaporation of light components (Schulte and de Vries 1985; Greaves et al. 1991). In order to confirm these results, we carried out reservoir-simulation studies presented in Fadaei et al. (2010). We have shown that the front has the shape of a cone, and we have performed a combustion/extinction analysis representing the results in a diagram of cumulative production vs. diffusion coefficient and matrix permeability. Before obtaining quantitative and qualitative comparisons, we need to characterize the systems we want to study. Therefore, we also carried out laboratory experiments using kinetic cells and combustion tubes. The kinetic-cell studies showed that the presence of carbonates has a significant effect on combustion kinetics. Our combustion-tube studies confirmed the previously observed coneshaped front. Previous studies reported in literature used heating elements along the combustion tube to regulate the temperature, which may have caused some undue heating of the core. To avoid that, we chose to use efficient insulation to minimize heat losses. Combustion advanced faster in nonconsolidated matrix, in which the permeability was higher than in consolidated matrix. The results showed that the presence of severe heterogeneities may prevent the combustion front from propagating. Several runs were performed for different air-injection rates and pressures and for different permeability contrasts between the matrix and the fracture. The next step of our work is the upscaling of ISC in the fractured reservoir at interwell scale on the basis of knowledge provided by simulation and experimental studies.

Pore-scale modelling of the coupled thermal and reactive flow at the combustion front during crude oil in-situ combustion

2018 ◽  
Vol 350 ◽  
pp. 776-790 ◽  
Author(s):  
Qianghui Xu ◽  
Wei Long ◽  
Hang Jiang ◽  
Cheng Zan ◽  
Jia Huang ◽  
...  
Keyword(s):  
Crude Oil ◽  
Combustion Front ◽  
Reactive Flow ◽  
Pore Scale ◽  
In Situ Combustion ◽  
Scale Modelling

Effects of Steam on Heavy Oil Combustion

2009 ◽  
Vol 12 (04) ◽  
pp. 508-517 ◽  
Author(s):  
Alexandre Lapene ◽  
Louis Castanier ◽  
Gerald Debenest ◽  
Michel Yves Quintard ◽  
Arjan Matheus Kamp ◽  
...  
Keyword(s):  
Crude Oil ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Combustion Front ◽  
Oil Viscosity ◽  
In Situ Combustion ◽  
Temperature Oxidation ◽  
Recovery Method

Summary In-Situ Combustion. In-situ combustion (ISC) is an enhanced oil-recovery method. Enhanced oil recovery is broadly described as a group of techniques used to extract crude oil from the subsurface by the injection of substances not originally present in the reservoir with or without the introduction of extraneous energy (Lake 1996). During ISC, a combustion front is propagated through the reservoir by injected air. The heat generated results in higher temperatures leading to a reduction in oil viscosity and an increase of oil mobility. There are two types of ISC processes, dry and wet combustion. In the dry-combustion process, a large part of the heat generated is left unused downstream of the combustion front in the burned-out region. During the wet-injection process, water is co-injected with the air to recover some of the heat remaining behind the combustion zone. ISC is a very complex process. From a physical point of view, it is a problem coupling transport in porous media, chemistry, and thermodynamics. It has been studied for several decades, and the technique has been applied in the field since the 1950s. The complexity was not well understood earlier by ISC operators. This resulted in a high rate of project failures in the 1960s, and contributed to the misconception that ISC is a problem-prone process with low probability of success. However, ISC is an attractive oil-recovery process and capable of recovering a high percentage of oil-in-place, if the process is designed correctly and implemented in the right type of reservoir (Sarathi 1999). This paper investigates the effect of water on the reaction kinetics of a heavy oil by way of ramped temperature oxidation under various conditions. Reactions. Earlier studies about reaction kinetic were conducted by Bousaid and Ramey (1968), Weijdema (1968), Dabbous and Fulton (1974), and Thomas et al. (1979). In these experiments, temperature of a sample of crude oil and solid matrix was increased over time or kept constant. The produced gas was analyzed to determine the concentrations of outlet gases, such as carbon dioxide, carbon monoxide, and oxygen. This kind of studies shows two types of oxidation reactions, the Low-Temperature Oxidation (LTO) and the High-Temperature Oxidation (HTO) (Burger and Sahuquet 1973; Fassihi et al. 1984a; Mamora et al. 1993). In 1984, Fassihi et al. (1984b) presented an analytical method to obtain kinetics parameters. His method requires several assumptions.

Chemical Aspects of In-Situ Combustion - Heat of Combustion and Kinetics

1972 ◽  
Vol 12 (05) ◽  
pp. 410-422 ◽  
Author(s):  
J.G. Burger
Keyword(s):  
Porous Media ◽  
Combustion Front ◽  
Combustion Process ◽  
Heat Of Combustion ◽  
Oxidation Reactions ◽  
In Situ Combustion ◽  
Oxidation Of Hydrocarbons ◽  
Kinetics Of ◽  
Heat Released

Abstract General remarks on the oxidation reactions of hydrocarbons involved in in-situ combustion are followed by estimates of heat releases. A formula is derived for computing the heat of combustion in the high-temperature zone. Reaction kinetics in porous media applied to the in-situ combustion porous media applied to the in-situ combustion process is discussed. It is observed that there is process is discussed. It is observed that there is some similarity between the kinetics of reverse and partially quenched combustion processes. The influence of additives on crude oil oxidation in porous media is illustrated by effluent gas analysis experiments. Some information concerning the values of the kinetic parameters of the reaction controlling the velocity of a reverse combustion front is derived from the interpretation of laboratory experiments, using a numerical model. Introduction A great deal of laboratory and field work has been done on thermal recovery methods. The importance and limitations of these techniques have been extensively studied. However, some of the chemical and physical problems involved that needed to be elucidated were studied as part of a research program carried out by the Institut Francais du Petrole. Specific problems are created by in-situ combustion since both the possibility of combustion-front propagation and the air requirement are controlled by the extent of the exothermic oxidation reactions. Actually, the propagation velocity of a forward combustion front depends on the fuel formation and combustion, which are controlled by the kinetics of these processes; furthermore, the peak temperature is related to the heat released by oxidation and combustion reactions. Therefore, a quantitative estimation of the parameters related to the chemical aspects of the parameters related to the chemical aspects of the process is a necessary step in studying combustion process is a necessary step in studying combustion through a porous medium. General and theoretical considerations on heats of reaction and kinetics are presented and illustrated by experimental data and numerical interpretation of the results. HEAT RELEASED IN THE OXIDATION OF HYDROCARBONS DESCRIPTION OF OXIDATION REACTIONS A great number of reaction products are produced by the oxidation of hydrocarbons. By taking into account the formation of bonds between one carbon atom and oxygen, it is possible to derive the most important processes. Complete combustion, (1) 2 2 2 2H H3R C R  +  ---- O  → RR  +  CO + H O Incomplete combustion, (2) 2 2H H R C R  +  O  → RR  +  CO  +  H O Oxidation to carboxylic acid, (3) 2 2 2H OH H3 OR C H  +  --- O  → R - C  +  H O Oxidation to aldehyde, (4) H H R C Oxidation to ketone, (5) 2 2H O H R C R '  +  O  → R - C - R;  +  H O Oxidation to alcohol, (6) R' R; R C H SPEJ p. 410

scholarly journals Mutual Dynamics of Heat Dissipation and Oil Displacement Fronts during In-Situ Oil Combustion. One-Dimensional Simulation

2019 ◽  
Vol 62 (5) ◽  
pp. 445-458
Author(s):  
I. A. Koznacheev ◽  
K. V. Dobrego
Keyword(s):  
Oxygen Concentration ◽  
Combustion Front ◽  
Heat Dissipation ◽  
Front Velocity ◽  
Maximum Temperature ◽  
Oil Viscosity ◽  
One Dimensional ◽  
Oil Displacement ◽  
Displacement Front

One-dimensional axis-symmetrical and plane-symmetrical problem of propagation of the combustion and displacement fronts in oil-containing layer in situ has been considered numerically. Two combustible components, viz. liquid (oil) and solid (kerogen, oil sorbate), were considered. The influence of the blast rate, liquid component viscosity, oxygen concentration in blasted air and heat losses (the width of the oil-containing layer) on the dynamics of the heat dissipation and displacement fronts is investigated. In the cylindrical system the oxidizer flow to the combustion front is reducing over time; and the shift-down of the maximum temperature from the solid combustion front to the oil displacement front takes place (the combustion front “jump”). The time of the “jump” may vary from tenths to hundreds of days and the distance of the shift, – up to 10 or more meters, depending on the parameters of the system. After the “jump”, the combustion rate and maximum temperature continue to deteriorate and after the period of time close to the time lapse before the “jump” the chemical reaction ceases. Herewith the transition of combustion to the liquid phase after the “jump” doesn’t influence notably on oils displacement front speed. The time of the “jump”, as well as the velocity of the mutual combustion (maximum temperature) front and displacement front removal nearly linearly depends on incoming gas blast rate and non-linearly – on oil viscosity. When viscosity is low, the displacement front rapidly runs away from the combustion front, time of the “jump” retards and the distance between the fronts at the instance of the “jump” may reach 10 m or more. The oxygen concentration in the gas being blasted influences significantly on the mutual dynamics of the combustion and displacement fronts since combustion front velocity is proportional to oxygen concentration and displacement front velocity is independent on it. Oxygen enrichment of the gas being blasted just after the “jump” may help localize the area of heat release (combustion) near the oil displacement front. The mentioned manipulation may be utilized for sustainability control of the displacement front. However for its practical implementation it is necessary to have information on concentration and temperature fields inside the layer, which may be obtained from indirect data and via modeling. The results of investigation may be utilized for development of technical projects of oil recovery via in-situ combustion.

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