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.

scholarly journals One-Dimensional Simulation of the In-Situ Oil Combustion with Consideration to Fluid and Solid Combustible Components

2019 ◽  
Vol 62 (1) ◽  
pp. 47-60 ◽  
Author(s):  
I. A. Koznacheev ◽  
K. V. Dobrego
Keyword(s):  
Combustion Wave ◽  
Combustion Front ◽  
Exothermic Reaction ◽  
Heat Content ◽  
Maximum Temperature ◽  
Thermal Front ◽  
Liquid Component ◽  
One Dimensional ◽  
Combustion Site

The one-dimensional axisymmetric problem of initiation of a combustion wave in an oil-saturated reservoir is solved numerically. Two combustible components, viz. liquid (oil) and solid (kerogen, oil sorbate) were considered. The influence of the abovementioned components on time of the hot site ignition and combustion front speed was simulated and analyzed. It was demonstrated that growth of the mass fraction of liquid component (the total heat content being preserved) results in retard of formation of the hot site near the well and in reduction of the maximum temperature of the combustion wave, disregarding of the higher reactivity of liquid combustible. Simulation revealed existence of the two “peaks” of thermal front velocity. The first one corresponds by time to ignition of combustion site. The second one corresponds to a moment when the solid component combustion front overrides the oil displacement front. Calculations shown, that thermal wave propagation velocity, at least after passing the “peaks” and transition to quasi-steady regime, does not considerably depend on mass traction of the fluid component in the system. A typical term of the exothermic reaction site formation may increase from 50 to 200 days in case of growth of the liquid component content from 30 to 80 mass % at the considered thermal conditions in the oil reservoir. Thus, the implementation of the thermo-gas method in high-productive layers increases the likelihood of difficulty of initiation of a fire. Therefore, the study of the regularities of intra-combustion in such cases is of a particular interest. For instance, the task of combustion site ignition may be resolved by increase of oxygen content in blowing-gas or by means of non-steady (periodical) blowing. It is found that taking into consideration of highly reactive liquid component results in widening (diffusion) of the thermal front, which may play positive role in its spatial thermo-hydrodynamic stabilization. The results of simulation may be utilized for development of technical projects of oil recovery via in-situ combustion, for designing of furnaces utilizing multicomponent fixed layer fuels and for thermochemical investigation of multicomponent fuels.

Study on In Situ Carbon Dioxide-Generation Flooding

2012 ◽  
Vol 502 ◽  
pp. 179-183
Author(s):  
Hong Jing Zhang ◽  
Shuang Bo Dong ◽  
Zhe Kui Zheng
Keyword(s):  
Carbon Dioxide ◽  
Oil Recovery ◽  
Flow Direction ◽  
Physical Models ◽  
Viscosity Reduction ◽  
Oil Viscosity ◽  
Foamy Oil ◽  
Oil Displacement ◽  
Generation Technology

Aiming at the source and corrosiveness of carbon dioxide, the in-situ carbon dioxide generation technology to enhance oil recovery was proposed。This paper presents the in-situ carbon dioxide generation technology mechanism, the expansion, viscosity reduction; oil-displacement efficiency and foamy oil of this technology were experimentally evaluated by using microscopic models and physical models. The experimental results indicated that the in-situ carbon dioxide generation technology could be used to produce enough carbon dioxide and get good efficiencies of oil expansion, reduction of viscosity and enhancement of oil displacement. Under the conditions of 2010mPa•s in oil viscosity, 60°C and 10MPa, the volume of oil could be expanded by25%, and the viscosity of oil can reduced to 52.7% , and the CO2 can displacement，restraining viscous fingering and changing liquid flow direction and carrying the residual oil.

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.

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

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.

Experimental Study on the Displacement Performance of Heat-Resistant Polymer

2014 ◽  
Vol 675-677 ◽  
pp. 1495-1499 ◽  
Author(s):  
Tao Ping Chen ◽  
Biao Qiu
Keyword(s):  
Polymer Flooding ◽  
Displacement Efficiency ◽  
Oil Viscosity ◽  
Permeability Ratio ◽  
Ratio Increase ◽  
Displacement Effect ◽  
Oil Displacement ◽  
Heat Resistant ◽  
Homogeneous Core ◽  
Oil Displacement Efficiency

The displacement performance of heat-resistant polymer is evaluated with the artificial cores and natural cores under 95°C. The best concentration of BH heat-resistant polymer is 1500 mg/L, and the best slug is 0.6 PV on the condition of the average permeability is 600×10-3μm2 of the homogeneous core and the oil viscosity is 2.3mPa • s. Under the best concentration and the PV size, BH heat-resistant polymer solution has better displacement effect for the artificial double core whose permeability ratio is less than 4. When permeability ratio exceed 4, the displacement affect no longer increase. When the mobility ratio increase from 0.05 to 0.2, for the artificial cores, the recovery of polymer flooding reduce by 3.17%, and for the natural cores, the recovery of polymer flooding reduce by 2.26%. The recovery of BH polymer that is aged for 90 days after vacuumed is 32.29%. Comparing with the fresh BH polymer, it is lower by 6.56%. That is to say that the aged BH polymer still has good oil displacement efficiency.

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.

The front velocity of the simple epidemic

1979 ◽  
Vol 16 (2) ◽  
pp. 409-415 ◽  
Author(s):  
John C. Wierman
Keyword(s):  
Propagation Rate ◽  
Front Velocity ◽  
One Dimensional ◽  
The One

The propagation rate of the one-dimensional stochastic simple epidemic converges almost surely to a front velocity for the epidemic. Percolation methods are used in the proof.

A Convective-Heat Transfer Model for Underground Combustion

1968 ◽  
Vol 8 (04) ◽  
pp. 323-324
Author(s):  
C.H. Kuo
Keyword(s):  
Temperature Distribution ◽  
Convective Heat ◽  
Heat Generation ◽  
Temperature Rise ◽  
Combustion Front ◽  
Combustion Process ◽  
Front Velocity ◽  
Paradoxical Result ◽  
Heat Recuperation ◽  
Heat Front

In the underground combustion process, part of the heat generated at the combustion front is carried downstream by convection. Temperature distribution in the combustion process can be obtained by including a delta function for heat generation at the combustion surface. This is similar to the hot-fluid injection model of Lauwerier. The dimensionless temperature in the reservoir, phi T1(x, t), and the overburden, phi T2(x, y, t), are as follows: ..........................................(1) ..........................................(2) The ratio R of the heat-front velocity, u, h, to the combustion front velocity, uc, is one of the most important factors governing the temperature distribution in the pay zone. For cases of ub less than uc, no heat is carried ahead of the combustion front and the temperature at the combustion front remains constant for all times. The fraction of the heat stored between the heat front and the combustion front decreases as the time increases. This is because more of the heat is consumed in heating the formation behind the heat front and in heating the cap and bass rock. A more advantageous condition obtains for uh is greater than uc. For this case, the formation ahead of the combustion front is preheated and the amount of heat in this region increases with time. Therefore, due to heat generation and preheating, the total temperature rise at the combustion front also increases with time. Eq. 1 also shows that the temperature at the combustion front is higher at a given time for a thinner reservoir. This seemingly paradoxical result takes place because the amount paradoxical result takes place because the amount of heat recovered from the overburden and subrock upstream of the combustion front is almost independent of the pay zone thickness. On the other hand, this heat is distributed in the pay zone, which has a heat content directly proportional to the formation thickness b. For thin reservoirs, therefore, the temperature rise in the pay zone due to heat recuperation is higher than that in thick reservoirs. For very thick pay zones (h-oo) there would be no heat recuperation, and consequently the combustion- front temperatures would be lowest. For many cases encountered, uh is smaller than uc. Convective-heat transport. ahead of the combustion front can be achieved by increasing uh to obtain the condition uh, >uc. The wet and partially quenched combustion processes have a similar objective. The temperature at the combustion front, however, decreases as the uh/uc ratio increases. If this temperature should fall below the ignition point, the fire would die out. Consequently, at any point, the fire would die out. Consequently, at any time there exists a maximum ratio of uh/uc for which the formation ahead of the combustion front can be heated to increase oil mobility while combustion is maintained. For the case where the heat front moves faster than the combustion front (uh is greater than uc), the downstream heat efficiency E can be derived by applying the integration method given in Ref. 3. P. 323

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