Parameters Determination during In Situ Combustion of Liaohe Heavy

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Parameters Determination during In Situ Combustion of Liaohe Heavy Oil Xian Zhang, Qicheng Liu, and Hongchang Che Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/ef400095b • Publication Date (Web): 01 May 2013 Downloaded from http://pubs.acs.org on May 7, 2013

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Parameters Determination during In Situ Combustion of Liaohe Heavy Oil Xian Zhang, *,† Qicheng Liu,‡ Hongchang Che§ †

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University,

Sichuan, Chengdu 610500, People’ republic of China ‡

§

Liaohe Oilfield Exploration and Development Institute, Liaoning, Panjin 124221, People’ republic of China PetroChina International Iraq, Beijing 100011, People’ republic of China

ABSTRACT: Laboratory in situ combustion experiments were performed to determine the basic parameters prior to field projects, using a self-made combustion tube and S1-38-330 crude oil from Liaohe Oilfield. These basic parameters, the oil’s ignition temperature range of 340 to 360℃, the apparent atomic H/C ratio of 1.044, the oxygen utilization of 52.15%, the oil recovery factor of 78.6%, the combustion front movement velocity of 0.20 cm/min, the maximum fuel consumption of 28.99kg/m3 and the maximum air requirement of 298.6 Nm3/m3, etc., were determined in the experiments. The gas chromatograms showed that the crude oil had undergone a series of pyrolysis reactions during combustion, which could also be proved via the results of aromatics mass spectrometry that anthracene was generated during this process. 1. INTRODUCTION In situ combustion (ISC) is a thermal recovery process in which heat is generated within the reservoir by igniting a part of oil-in-place to improve the flow of the unburnt region.1 This is in contrast to the hot fluid injection method in which heat is generated at surface and

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transported to the reservoir by a fluid. In this process oil in the reservoir is ignited and fire is sustained by air injection. As in any combustion reaction, oxygen combines with oil forming carbon dioxide and water and releasing heat. The crude oil composition affects the amount of energy released. Ignition of reservoir crude is the first requisite for underground combustion. In the field, the ignition is started either by electrical means or a gas burner, and in some cases ignition can be spontaneous. High temperature during burning causes the lighter fractions of oil ahead of the flame to vaporize, leaving a heavy residual coke or carbon deposit as fuel to be burned. The vaporized light components and steam formed by combustion are carried forward until they condense upon contacting cooler portions of the reservoir. The flame moves forward through the reservoir only after burning all deposited fuel. Burning some of the oil in situ creates a combustion zone that moves through the formation toward production wells, providing a steam drive and an intense gas drive for the recovery of oil. The ISC method has been utilized for over 80 years in more than two hundred fields around the world, mostly the reservoirs containing oil too viscous or "heavy" to be produced by conventional means.2-4 It is normally employed as a recovery process in more difficult reservoirs as a secondary or tertiary process. During the ISC process, high displacement efficiency can be achieved, although some oil is burned and not produced. And the injection fluid, air, can be readily available. However, it does have some disadvantages according to the previous studies, such as the gas/steam override tendency, a large investment of ISC installation, and hazardous gases produced, ect.5-8 In China, the ISC technique is still on the


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preliminary stage of experiments. The displacement efficiency of the ISC process has been strongly associated with the reservoir and its crude, air injection, igniting temperature and burning temperature, etc. For example, fuel depositional characteristics determine the amount of air required for fireflood. Reservoir properties determine necessary air injection rates and needed combustion front movement. Both determine the size of compressor facility necessary for a specific project, which generally represents a considerable investment. In order to support an ISC field application and mitigate the investment risks, combustion tube experiments are mandatory to determine the basic parameters needed to design and implement field projects, such as the apparent atomic H/C ratio, the volume of injected air and the volume of consumed fuel, etc. These data will be used to make predictions of field test performance. As Sarathi pointed out, “combustion tube studies are the necessary first step in the design of an ISC project”.9 This paper presents with laboratory combustion of Liaohe heavy oils using self-made ISC experimental set-up. 2. EXPERIMENTAL SECTION 2.1. Apparatus. Figure 1 gives a picture of the main body of the designed combustion tube system. The combustion tube assembly consists of a thin walled corrosion resistant tube housed inside a pressure jacket. The pressure jacket is fabricated out of carbon steel and designed to withstand the desired operating pressure. The maximum working temperature is 900℃, and the maximum working pressure is 3MPa. The annular space between the tube and the pressure jacket is filled with alumina silicate to lower heat losses. There are compensating


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heaters mounted along the length of the tube at equally spaced interval to match the wall (heater) temperature with the tube's center temperature at each heating zone. The combustion tube system can be used to conduct dry combustion or wet combustion experiments. Heat compensation and high air injection flux can be achieved during the experiments. It simulates the dynamic process of combustion between the injector and the producer, and monitors the produced oil and gases. The major components of the experimental apparatus used in the experimental setup are shown schematically in Figure 2, which consists of the following interrelated parts: air injection unit, ignition unit, combustion tube, gas-liquid separator and gas analysis unit and data acquisition system. Figure 3 gives the section view of the combustion tube, which was made of stainless steel and comprised 39 thermocouples (3×13) measuring the temperature variation. The dimension of the tube is 42cm long ×9cm wide ×3.6cm high, which refers to internal parameters of the tube. The wall thickness is 6mm. The tube was mounted in vertical position and it could be axially rotated and fixed anywhere during experiments, which contributed to minimizing gravity segregation effect. There are 39 thermocouples evenly distributed in the tube. Each thermocouple was 3.2cm away from any adjacent one. One pressure measurement point was located in the center of the combustion tube to collect the pressure variation data. The igniter was basically an electrical heater connected to voltage regulator and power pack. It was inserted to the simulated injection well and its heating power could be adjusted through voltage regulator to maintain a temperature near the injection well higher than the crude’s auto ignition temperature. The ignition temperature was originally set at 500℃. The air injection unit comprises air compressor, dry


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receptacle and flow meter, by means of which gas flow through the system can be accessibly controlled and precisely measured. Thermocouples were connected to data acquisition system. The temprature and pressure data could be automatically recorded and demonstrated in computer. A gas chromatograph was used for analysis of the produced gas composition. 2.2. Procedure. The combustion tube was packed with the quartz which can represent the characteristics of the reservoir in Liaohe Oilfield. The heavy crude oils from the candidate wells were mixed with quartz to get oil sands with same oil saturation. The experimental procedures are listed as below: (1) Measure the permeability of the sandpack and the thermophysical parameters. (2) Leakage test the tube by means of nitrogen gas injection. If test is good, bleed off and vacuum the tube. Saturate the tube with water in underbalanced condition and calculate the porosity based on the water volume and the tube volume. (3) Saturate the tube with the crude oil until the initial temperature designed, calculate the original oil saturation and bound water saturation. (4) Nitrogen gas should be injected to confirm the connectivity between the injection well and the production well prior to ignition and during this process the initial designed temperature of the tube should be established. These will guarantee the continuous gas release during ISC process. (5) Rise the temperature of high-temperature air oven until the designed temperature. Open the production well and inject air (as per requirements of designed temperature, pressure, and injection rate) into the injection well and start igniting meanwhile. Monitor through the whole


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ISC process and record data using data acquisition system. (6) Bleed off pressure and maintain a room temperature of the combustion tube post ISC experiment. Nipple down the tube and observe the combustion results. Two ISC experiments using different crude oils from S1-38-330 and L37-45-562 were conducted. We take the experiment of S1-38-330 as the example to study the basic characteristics of in situ combustion, then compare the results of the two experiments in order to identify the impact of oil and geological condition on the combustion results. The crude oil properties and the basic laboratory parameters of S1-38-330 are given in Table 1. Because the porosity (45.72%) of the sandpack were relatively high, a high air injection flux of 60 Nm3/(m2·h) was adopted. The air injection rate was then determined to be 0.1944 Nm3/h based on the air injection flux and the cross sectional area of the tube. 3. RESULTS AND DISCUSSION 3.1. Temperature variation and ignition temperature. Figure 4 shows the temperature distribution during the frontal advancement of the combustion zone in the tube. All the data are recorded during the stabilized propagation of the front in the tube after the initial ignition transient effects had settled down. This is necessary because the tube pack assume to represent a reservoir element located at some distance downstream of the combustion front and is unaffected by transient start-up effects. The whole combustion period (combustion duration) was 189 minutes. Data was being recorded from 0min which represented the moment when the combustion was stabilized. The arrow in Figure 4 was the air flow direction. The combustion front is the highest temperature zone. It is a thin region where


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oxygen combines with the fuel and high temperature oxidation (HTO) occurs. With combustion front moving forward, the combustion zone slowly but continuously expanded. Temperature measurements made during a tube run can be used to monitor the frontal advancement of the burn (the combustion front velocity). The combustion front velocity is directly proportional to the amount of oxygen supplied (air flux) and inversely proportional to the amount of fuel laydown at constant air flux.10-13 From 0min to 74min, the combustion front moved at a relatively low velocity(0.14cm/min) because the low air flux of 31Nm3/(m2·h) was adopted at this stage. When the average air flux was increased to 39 Nm3/(m2·h) at 102min, the combustion front velocity achieved at 0.17cm/min, which was eventually increased to 0.2cm/min when the air flux reached 60 Nm3/(m2·h) in the end. With the frontal advancement of the combustion zone, the combustion front velocity increased because the air flux was increased and more light components and less coke were produced during the combustion. The coke produced is the major fuel to support combustion during ISC. The combustion front velocity was a lot higher at the latter stage. Figure 4 also shows the peak combustion temperature was up to 663℃ and the continuous air flow cooled down the burnt zones behind combustion front. The combustion front moved forward at the average velocity of 0.20cm/min. The oil’s ignition temperature is a very important parameter for the design of igniter power and igniting time. We select various TMPs in the combustion tube to collect data of temperature variation. The temperature-time relationship curves of various TMPs are given in Figure 5. The peak temperature of different TMPs demonstrates the process of the


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advancement of the combustion front with the combustion time increment. As is shown in Figure 6, through the derivatives of temperature-time relationship curves, the temperature variation rate can be obtained. Before the crude being ignited, heat is transferred through heat conduction of the oil sands. The rate of temperature variation is relatively low during this process. After the crude being ignited, however, the combustion generates a large amount of heat resulting in the sharp increase of the temperature (high temperature variation rate) in the combustion zones. With the combustion front moving forward, the temperature variation rate starts going down at the measure points. As the consequence, the maximum value of the temperature variation rate appears at the moment when the crude is ignited. The crude’s ignition temperature can be estimated at the temperature-time relationship curves once the exact igniting time was pinpointed at their derivatives. The calculation results show that the ignition temperature of S1-38-330 crude oil ranges from 340 to 360℃. 3.2. Gas composition change. The comparison of the composition of inlet air and outlet gases is given in Table 2. The light component (C1～C4) was found in outlet gases, indicating that the original oil may undergo an intense thermal cracking or distillation. According to laboratory pyrolysis studies on heavy crudes,14,15 during distillation the oil loses most of its light gravity and part of its medium gravity fractions. At higher temperatures, intense cracking of the oil occurs in which the hydrocarbon lose small side groups and hydrogen atoms to form less branched compounds that are more stable and less viscous. And the existence of CO and the increase of the concentration of CO2 demonstrate the oxidation and the combustion in the combustion tube.


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The oxygen utilization can be calculated using the relationship: Y = 1−

79c(o 2 ) 21c( N 2 )

(1)

Where Y ——oxygen utilization, %； c(o2 ) ——O2 percentage in produced gases, %；

c( N 2 ) ——N2 percentage in produced gases, %. The oxygen utilization at the stabilized period in the ISC experiment of S1-38-330 crude was 52.15%. This is an indication that more than half oxygen was consumed in the high temperature zone to produce CO and CO2. Besides oxygen utilization, the apparent atomic H/C ratio is also a very significant parameter to evaluate the stability of the combustion. There are many chemical reactions that occur in the tube during combustion. These include low temperature oxidation of oil, thermal cracking or pyrolysis, and high temperature oxidation. Even though significant LTO and pyrolysis reactions do occur in the tube, generally only the HTO reaction is assumed to represent the process and used to analyze the combustion tube data. That is why it is called “apparent”. Therefore the calculation based on HTO is only an approximation of the process.16 The apparent atomic H/C ratio can be calculated as per HTO (assuming all O2 consumed to form CO, CO2 and water) using the relationship: X =

1.06 − 3.06c(co) − 5.06(c(co2 ) + c(o 2 )) c(co2 ) + c(co)

Where X ——apparent atomic H/C ratio； c(o2 ) ——O2 percentage in produced gases, %； c(co) ——CO percentage in produced gases, %;


(2)

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c(co2 ) ——CO2 percentage in produced gases, %. During HTO, the value of the apparent atomic H/C ratio is relatively low, generally in the range from 1 to 3. During LTO, it increases ranging from 3 to 10. In this case the apparent atomic H/C ratio of S1-38-330 crude is 1.044.

3.3. Oil recovery factor. The average air flux for the stabilized combustion process was designed as 60 Nm3/(m2·h), while in the experiment the injection of variable air flux was adopted for the purpose that the ignition can be achieved and the combustion can move forward at a stabilized velocity. At the beginning air was injected at low air flux which would be adjusted afterwards with the combustion front advancement. The actual air flux and oil recovery factor during ISC experiment are given in Figure 7. The oil recovery factor was 78.6%, as is shown in Figure 7, and at the beginning the relatively low air flux resulted in the low oil recovery factor. When the air flux was increased to the peak, the oil recovery factor started increasing sharply, indicating that the high air flux not only supplies sufficient oxygen gas to support combustion but also provides gas drive to the crude oils. With the injection of variable air flux, the stabilized combustion front movement approached to the end of the combustion tube where a small part of coked oil sands were found. As is shown in Figure 8, the other parts of the combustion tube were efficiently swept leaving the oil sands turned into the white powder.

3.4. Fuel consumption and air requirement. Air requirement, defined as the volume of air required to burn a unit volume of the reservoir, determine the compression capacity


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needed, and is one of the most important parameters due to its effect on the overall project economics. The continuous air flow sustains and advances the combustion front in the tube. The temperature rises from initial reservoir temperature to the peak temperature at the combustion front. At high temperature, the oil remaining in the porous medium cracks into a volatile fraction and a non-volatile carbon rich hydrogen poor residue often referred to as "coke" which is the actual fuel for combustion. Many laboratory studies17-19 demonstrated the range of fuel consumption from 13 to 45 Kg/m3. Based on the oxygen gas consumption and the combustion front velocity, the fuel consumption can be calculated, the maximum of which was 28.99 kg/m3 in this case. Air requirement can be calculated based on the fuel consumption, the maximum of which was 298.6 Nm3/m3 in this case. The actual fuel consumption and air requirement during the ISC process are given in Figure 9.

3.5. The change of the crude oil properties. The specific gravity of S1-38-330 crude oil was 0.985 at 20℃, which became 0.970 post ISC experiment. And the viscosity also changed from the original 38670mPa·s (50 ℃ pre ISC) to 1411mPa·s (50 ℃ post ISC). These indicated the heavy crude oil had undergone a chemical change called pyrolysis resulting in the increase of the light composition and the upgrading of the heavy crude oil. Oil pyrolysis reactions are mainly homogeneous (gas-gas) and endothermic (heat absorbing) and involve three kinds of reactions: dehydrogenation, cracking and condensation. In the dehydrogenation reactions the hydrogen atoms are stripped from the hydrocarbon molecules, while leaving the carbon atoms untouched. In the cracking reactions, the carbon carbon bond of the heavier hydrocarbon molecules are broken, resulting in the formation of


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lower carbon number hydrocarbon molecules. In the case of condensation reactions, the number of carbon atoms in the molecules increases leading to the formation of heavier carbon rich hydrocarbons. In general short chain hydrocarbons undergo dehydrogenation and the larger molecules undergo cracking. Cracking reactions are usually initiated by the cleavage of the carbon-carbon bond, followed by the dehydrogenation reaction. The dehydrogenation molecules then recombine to form heavier molecules, eventually leading to the formation of "coke". Thus the larger straight chain molecules when subjected to sufficiently high temperature often produce "coke" and considerable amounts of volatile hydrocarbon fractions. In the condensation reaction the weak C-H bonds of the ringed molecules are broken and replaced by a more stable C-C bonds and leads to the formation of a less hydrogenated polyaromatic molecule. When subjected to further heating these condensation products losses more of the hydrogen and recombines to form heavier carbon rich polymolecules, eventually leading to the formation of large graphite like macromolecules. The gas chromatograms of S1-38-330 crude oil pre and post ISC are respectively shown in Figures 10 and 11. As is shown in Figure 10, normal alkanes in the crude oil almost totally disappear and there only remain some cycloalkanes with relatively higher anti-degradation abilities, e.g. gonanes, terpanes, etc. Due to the existence of heteroatom compounds, they cannot be separated chromatographically. This leads to high baselines and the form of large envelops in the chromatogram, which means there occurs serious biodegradation and the crude is quite heavy. In the total hydrocarbon gas chromatograms post ISC shown in Figure 11, there exist plenty of low-carbon normal alkanes and isomeric hydrocarbons found in the


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oil. Besides, the carbon numbers of main peaks change from the original C28~C30 to C13~C15 post ISC, which is almost same as the ordinary crude oils. It indicates that the thermal cracking or upgrading which the crude oil had undergone during combustion resulted in the increase in the content of light components and the decline in the content of heavy components of the crude oil, i.e. a few aliphatic chains or low-ring aromatic hydrocarbons originally linked to the structures of these complex macromolecules such as resin or asphaltenes, had cracked from the macromolecules during the thermodynamic process, forming the saturates and aromatics which can be normally found in ordinary crude oils. Individual saturates chromatograms of the crude oil pre and post ISC are given in Figures 12 and 13. These chromatograms indicate that there are mainly high-carbon (C27~C35) four-ring gonanes, five-ring hopanes and isomerism hydrocarbons in the crudes pre ISC, however, after combustion low-carbon (C13~C17) linear-chain normal hydrocarbons are mainly present and the content of branched-chain isomerism alkanes also increases, which majorly come from the crack from the side chains of macromolecules during ISC process. In addition, the content of isomerism hydrocarbons in the range from C27 to C35, such as four-ring gonanes and five-ring hopanes, relatively decreases, indicating the change of saturates content in these macromolecules. Individual aromatics chromatograms of the crude oil are given in Figures 14 and 15. With respect to aromatic constituent, as is shown in the chromatograms, the crude oil mainly contains high-ring polycyclic aromatics, such as the sulfurous benzothiophene with no less than four rings, the benzopyrene, etc. After combustion the heavy polycyclic aromatics


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almost disappear, and the content of low-ring aromatics increases dramatically, such as the monocyclic benzene, the bicyclic naphthalene, the tricyclic phenanthrene, etc. In the cracking reactions, the carbon-carbon bonds of the heavier hydrocarbon molecules are broken, resulting in the formation of lower carbon number (smaller) hydrocarbon molecules. On the other hand, some aromatic compounds undergo condensation reaction in which the weak carbon-hydrogen bonds of the ringed molecules are broken and replaced by more stable carbon-hydrogen bonds, leading to the formation of a less hydrogenated polyaromatic molecule. When subjected to further heating these condensation products loses more of the hydrogen and recombines to form heavier carbon rich polymolecules, eventually leading to the formation of large graphite like macromolecules. The individual phenanthrene series mass chromatograms (phenanthrene and its derivatives) pre and post ISC are given respectively in Figures 14 and 15. Anthracene was observed after the combustion, which caught the attention because it was obviously generated through thermal cracking during the ISC process. Anthracene is a solid polycyclic aromatic hydrocarbon consisting of three fused benzene rings. It is an isomer of phenanthrene, however, phenanthrene is more stable than its linear isomer anthracene. The appearance of anthracene was transient during the process of the geologic evolution and the formation of petroleum and it was not contained in mature petroleum samples. As a result, it can be regarded as a significant marked compound which reflects the fact that the heavy crude oil had undergone the thermal cracking during ISC process. In the process of thermal cracking, dealkytation is more likely to occur in the aromatic


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fraction of the crudes. The comparison between the side chain organics with more alkyl groups and those with less alkyl groups pre and post ISC can indicate the extent of the thermal cracking that the crude undergoes. As is shown in Figure 14 and 15, the content of 3-, 2-methylphenanthrene increased and the content of 9-, 1- methylphenanthrene decreased due to being subjected to high temperature during combustion. With the increase in the content of the alkyl substituent groups of benzene rings, the content of dimethylphenanthrene and trimethylphenanthrene was lowered in the process of combustion, and the tetramethyl phenanthrene totally disappeared at the end. All these phenomena indicated that the break of alkyl on the side chain of benzene rings is the main reaction form of crude oil’s thermal cracking.

3.6. ISC Comparison between two different wells. The crude oil from L37-45-562 was also used to conduct ISC experiments with same experimental procedures. The comparison results of S1-38-330 and L37-45-562 are given in Table 3. The apparent atomic H/C ratio and oxygen utilization of L37-45-562 is higher than S1-38-330, which means the L37-45-562 oil needs less air for combustion and it can achieve more profits under similar operating conditions. However, the oil recovery factor is a little lower. This may be caused by its high viscosity. Super high viscosity always brings a bad side to oil recovery.

4. CONCLUSIONS ISC experiments, using self-made apparatus and Liaohe heavy crude oil (from well S1-38-330), have been performed to determine the basic parameters. The velocity of the combustion front movement and the stability of the combustion process have also been


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evaluated. Based on these data, namely the oil’s ignition temperature range of 340 to 360℃, the apparent atomic H/C ratio of 1.044, the oxygen utilization of 52.15%, the oil recovery factor of 78.6%, the combustion front movement velocity of 0.20, the maximum fuel consumption of 28.99 kg/m3 and the maximum air requirement of 298.6

Nm3/m3, etc., it

will be accessible to design and implement field projects and to make predictions of field test performance. The specific gravity of S1-38-330 crude oil was 0.985 at 20℃, which became 0.970 post ISC experiment. And the viscosity also changed from the original 38670 mPa·s (50℃ pre ISC) to 1411 mPa·s (50℃ post ISC). Through the comparison of gas chromatograms of S1-38-330 crude oil pre and post ISC respectively, we can draw the conclusion that the crude oil had undergone a series of pyrolysis reactions during combustion resulting in the break of the heavier hydrocarbon molecules and the formation of lower carbon number (smaller) hydrocarbon molecules. The results of phenanthrene series mass chromatograms of S1-38-330 crude oil indicate the existence of anthracene after the combustion, which is an important marked compound that can reflect the fact that the heavy crude oil had undergone the thermal cracking during ISC process. The crude oil from L37-45-562 was also used to conduct ISC experiments. The comparison results between these two wells show that L37-45-562 oil can achieve better basic parameters of combustion. The crude properties exert great impacts on oil recovery.

AUTHOR INFORMATION Corresponding Author


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*E-mail: [email protected]. Tel: +86-13980912326.

Notes The authors declare no competing financial interest.

ACKNOWLEDGMENT The authors acknowledge Liaohe Oilfield Exploration and Development Institute, China, for financial support of this research.

REFERENCES (1) Musa B. Abuhesa and R. Hughes. Comparison of Conventional and Catalytic in Situ Combustion. Energy Fuels 2009, 23(1), 186–192. (2) Ghafoor Karimi; Arvin Khadem Samimi. In Situ Combustion Process, One of IOR Methods Livening the Reservoirs. Petroleum & Coal 2010, 52(2), 139-147. (3) Xu, H.-Y. H. In Situ Upgrading of Heavy Oil; University of Calgary: Calgary, AB, Canada, 2001. (4) Shah, A.; Fishwick, R.P.; Leeke, G.A.; Wood, J.; Rigby, S.P.; Greaves, M. Experimental Optimization of Catalytic Process In Situ for Heavy-Oil and Bitumen Upgrading. J. Can.

Petroleum Technol. 2011, 50 (11-12), 33-47. (5) Earlougher, R. C.; Galloway, J. R.; Parsons, R. W., Performance of the Fry In-Situ Combustion Project, J. Pet. Tech. 1970, 22(5), 551-57. (6) Buchwald, R.W.; Hardy, W.C.; Neinast, G. S., Case Histories of Three In-Situ Combustion Projects, J. Pet. Tech. 1973, 25(7), 784-792. (7) Casey, T. J. A Field Test of the In-Situ Combustion Process in a Near-Depleted Water


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Dirve Reservoir, J. Pet. Tech. 1971, 23(2), 153-160. (8) Gates, C. F.; Sklar, I. : “Combustion as a Primary Recovery Process, Midway-Sunset Field,” J. Pet. Tech. 1971, 23(8), 981-986. (9) Sarathi, P. : “In-Situ Combustion Handbook Principles and Practices,” Report DOE/PC/91008-0374, OSTI ID 3175, January 1999. (10) Ursenbach, M. G.; Moore, R. G.; Mehta, S. A. Air Injection in Heavy Oil Reservoirs - A Process Whose Time Has Come (Again). J. Can. Petroleum Technol. 2010, 49 (1), 48-54. (11) Moore, R.; Laureshen, C.; Mehta, S.; Ursenbach, M.; Belgrave, J.; Weissman, J.; Kessler, R. Technical Papers−Abstracts-IV Heavy oil (HO)−a downhole catalytic upgrading process for heavy oil using in situ combustion . J. Can. Petroleum Technol. 1999, 38 (13), 54. (12) Freitag, N. P. Evidence That Naturally Occurring Inhibitors Affect the Low-Temperature Oxidation Kinetics of Heavy Oil. J. Can. Petroleum Technol. 2010, 49 (7), 36-41. (13) Alamatsaz, A.; Moore, R. G.; Mehta, S. A.; Ursenbach, M. G. Experimental Investigation of In-Situ Combustion at Low Air Fluxes. J. Can. Petroleum Technol. 2011, 50 (11-12), 48-67. (14) Du, D. F.; Cui, J. Y; Lv, A. M. Pyrolysis upgrading behavior of heavy oil. Journal of

China University of Petroleum 2010, 34(4), 99-106. (15) Cheng, H.Q. Physical simulation research on basic parameters of in－situ combustion for super heavy oil reservoirs. Special Oil and Gas Reservoirs 2012, 19(4), 107-110. (16) Burger, J.; Sourieau, P.; Combarnous, M. Thermal methods of oil recovery, Editions


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Technip Paris France 1985. (17) Alexander, J. D.; Martin, W. L.; Dew, J. N. : “Factors Affecting Fuel Availability and Composition During In-Situ Combustion,” J. Pet. Tech. 1962, 14(10), 1156-1164. (18) Bae, J. H.: “Determination of the Kinetic Parameters from Differential Thermal Analysis.” J. Thermal Analysis 1972, 4, 61-69. (19) Kok, M. V.; Okandan, E. Kinetic analysis of in situ combustion processes with thermogravimetric and differential thermogravimetric analysis and reaction tube experiments.

J. Anal. Appl. Pyrolysis 1995, 31 (0), 63−73.


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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Figure 1. The main body of the combustion tube system


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Figure 2. Schematic flow diagram of the experimental apparatus


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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Figure 3. The distribution of temperature measurement points (TMP), pressure measurement point (PMP) and igniter in the combustion tube


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Figure 4. The temperature distribution during the frontal advancement of the combustion zone in the tube


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600

TMP 5 TMP 7 TMP 9 TMP 11 TMP 13 TMP 15

500

temperature, ℃

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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400

300

200

100

0 0

50

100

150

200

250

time, min

Figure 5. The temperature-time relationship curves of different TMPs


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80 TMP 5 TMP 7 TMP 9 TMP 11 TMP 13 TMP 15

-1

temperature variation rate/ ℃ min

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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60

40

20

0

-20

0

50

100

150

200

250

time/min

Figure 6. The temperature variation rate-time relationship curves rate of various TMPs


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100

180 160

120

2

60 air flux oil recovery factor

3

100 80

40 60 40

20

20 0 0

50

100

150

200

250

300

time, min

Figure 7. The air flux and the oil recovery factor during ISC


0 350

oil recovery factor, %

80

140

air flux, Nm /( m h)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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Figure 8. Oil sands pre-ISC and post-ISC


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350

35

30

3

25

3

air requirement, Nm /m

3

300

fuel consumption, kg/m

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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250

20

15

200

fuel consumption air requirement

10

150 5

0 0

50

100

150

200

100 250

time, min

Figure 9. Fuel consumption and air requirement during ISC experiment


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FID1 A, (Y09-8462.D) pA

90 80 70 60 50 40

20

40

60

80

100

Figure 10. S1-38-330 crude oil total hydrocarbon gas chromatogram pre ISC


min

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FID1 A, (Y-090803.D) pA 225 200 175 150 125 100 75 50 20

40

60

80

100

Figure 11. S1-38-330 crude oil total hydrocarbon gas chromatogram post ISC


min

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ADC1 B, ADC1 CHANNEL B (B09-0059.D) mv 700 600 500 400 300 200 100

10

20

30

40

50

Figure 12. S1-38-330 crude oil saturates gas chromatogram pre ISC


60

min

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ADC1 B, ADC1 CHANNEL B (B09-0063.D) mv 600 500 400 300 200 100

10

20

30

40

50

Figure 13. S1-38-330 crude oil saturates gas chromatogram post ISC


60

min

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ADC1 B, ADC1 CHANNEL B (B09-0070.D) mv 120

100

80

60

40 10

20

30

40

50

Figure 14. S1-38-330 crude oil aromatics gas chromatogram pre ISC


60

min

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ADC1 B, ADC1 CHANNEL B (B09-0069.D) mv 160 140 120 100 80 60 40 10

20

30

40

50

60

Figure 15. S1-38-330 crude oil aromatics gas chromatograph post ISC


min

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Figure 16. The phenanthrene series mass chromatograms pre ISC


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Figure 17. The phenanthrene series mass chromatograms post ISC


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Table 1. The crude oil properties and the basic laboratory parameters parameters oil S.G(20℃) viscosity(50℃) sand mass oil mass porosity original oil saturation air injection rate designed average air flux designed igniting temperature outlet pressure combustion duration combustion front movement velocity peak combustion temperature O2 percentage in produced gas CO2 percentage in produced gas CO percentage in produced gas apparent atomic H/C ratio oxygen utilization fuel consumption air requirement air-oil ratio oil recovery factor

unit

value

/ mPa·s g g % % Nm3/h Nm3/(m2·h) ℃ MPa min cm/min ℃ % % % / % Kg/m3 Nm3/m3 Nm3/m3 %

0.985 38670 1588 278 45.72 56.0 0.1944 60 500 1.0 189 0.20 663 10.11 6.82 3.22 1.044 52.15 28.99 298.6 2345.4 78.6


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Table 2. Gas composition change during ISC process composition

O2

N2

CO

CO2

C1

C2

C3

iC4

nC4

C6+

inlet air, % outlet gases, %

21.80 10.11

77.78 79.48

/ 3.22

0.03 6.82

/ 0.22

/ 0.06

/ 0.06

/ /

/ /

/ 0.02


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Table 3. ISC comparison results between S1-38-330 and L37-45-562 properties well

viscosity

S.G （20℃） 3

（50℃）

apparent

combustion front

oil’s auto

atomic

movement

ignition

H/C ratio

velocity, cm/min

temperature, ℃

oxygen

oil recovery

utilization, %

factor, %

g/cm

mPa·s

L37-45-562

0.9718

44240

1.413

0.148

334～368

84.32

75.3

S1-38-330

0.9850

38670

1.044

0.200

340～360

52.15

78.6


Parameters Determination during In Situ Combustion of Liaohe Heavy

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