Experimental Evaluation Of In Situ Combustion In Naturally Consolidated Cores

Petit, H.J.M.

doi:10.2118/90-06-05

Cited by 3 publications

(2 citation statements)

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“…That is the reason for the difficulty in research of the self-ignition process with combustion tube tests. Usually the quasi-adiabatic regime is performed during combustion experiments, when the inside and outside temperature difference is about 10 °C. ,, …”

Section: Introductionmentioning

confidence: 99%

“…Usually the quasi-adiabatic regime is performed during combustion experiments, when the inside and outside temperature difference is about 10 °C. 12,14,15 Both isothermal 16−22 and adiabatic 23−27 experiments performed for crude oils have the goal to explore initial stages of oxidation and possibility of self-ignition. This means that experiments are performed at reservoir conditions or not much different from the reservoir conditions.…”

Section: Introductionmentioning

confidence: 99%

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Chain Reactions Approach to the Initial Stages of Crude Oil Oxidation

Ushakova

Zatsepin

2018

Energy Fuels

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The paper focuses on the problem of the crude oil self-ignition in situ, which has not yet been solved in the general case and for a particular oilfield as well. To solve the problem of ignition, we approached from a theoretical point of viewapplied the theory of chain reactions to the description of the initial stages of oxidation. The obtained dependences of heat release on time should be of a general nature for experiments in which self-ignition occurred (we called them high rate experiments) and for experiments in which fuel formation was observed (low rate experiments). We first demonstrated this relationship in the experiments we conducted by high pressure rate calorimeter (PDSC). And then we analyzed the various experiments from literature sources. The novel results of the presented approach show the probabilistic nature of the ignition and the presence of a group of processes that do not lead to ignition, in which the free radicals are not sufficiently active and the heat sink exceeds the heat release. Instead of the heat balance, a new ignition criterionφ-factor for chain reaction, the difference in the rate of formation and death of free radicalsis derived. A positive value of φ-factor indicates the increase of energy in the system and the ignition by the chain mechanism, while a negative value indicates the attenuation of the reaction and the formation of oxidized compounds without ignition. The PDSC experiments with light crude oil oxidation were conducted under various heating rates in order to explore the ignition temperature–time dependence (the example of high rate experiments). The results show the same dependence of the process time on temperature predicted theoretically. The other types of high rate experiments (adiabatic experiments, combustion tube experiments) and low rate oxidation experiments from literature sources are also considered in terms of our approach. The comparison of different types of experiments with the obtained mathematical formulas gives a good agreement. The low rate oxidation dependences refer to the negative values of φ-factor, and high rate oxidation refers to positive φ-factor modes. Both types of experiments are in good consistency with the theoretically obtained dependence and show that the model of the chain reaction approach works well. Thus, the chain reaction approach to the ignition mechanism gives one a good consistency with experimental data and can be applied for the prediction of ignition time for air injection projects. The other result of our approach is the difference between heavy and light oil oxidation in low and high rate processes. In high rate processes, free radicals are active enough for igniting the oil, and light oils contain more free radicals of this type and are more reactive for ignition. Heavy oils have better affinity for fuel formation and oxygen addition reactions. So heavy oils can usually ignite at higher temperature than light oils.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chain Reactions Approach to the Initial Stages of Crude Oil Oxidation

Ushakova

Zatsepin

2018

Energy Fuels

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Design Parameters and Technique Evaluation of Combustion Processes from Tube Testing

Yatte¹,

Ramirez

Navarro³

et al. 2013

All Days

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In situ combustion (ISC) is one of the improve recovery methods with a high potential to increase the recovery of heavy crude oil. Although we mentioned this major advantage, this process has not being used in Colombia yet. This fact due mainly to the complexity of the involved phenomenon, therefore a field project must be design after extended laboratory investigation. Experimental tests in combustion tubes made through the main conditions in the oilfield have being the process' evaluation tool with the highest acceptance. These tests show the speed and stability of the combustion front and the obtained results from the production's analysis of fluids, mainly the ones of the exhaust gases. It is possible to calculate the basic combustion parameters by using: combustible consumption, required air, air- combustible relation, hydrogen- carbon atomic, and oxygen use. The parameters mentioned before let, trough different scaling analytic methods to evaluate the technical and economic viability of the process in the field. In this work was developed a computational tool that allow calculating the design parameters through different scaling analytic methods Nelson & McNeil, Gates & Ramey y Moore et al). Comparing the results got from the different described methods, when scaling two tests in a combustion tube, they show similar numbers. Taking into account that Nelson and McNeil's method is the most useful one due to the oilfield characteristic, it was made a sensitivity of operational parameters and the result permitted to study the relation between the oilfield operational variables

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Comparative Study of In-Situ Combustion Tests on Consolidated and Crushed Cores

Askarova

Popov

Maerle

2022

SPE Reservoir Evaluation &Amp; Engineering

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Summary A significant amount of oil is contained in carbonate reservoirs, but only half of that oil can be produced by secondary enhanced oil recovery (EOR) methods. However, substantial improvements were made in EOR techniques and the prediction of carbonate reservoir performance within the last decades. Nevertheless, existing flow-simulation computer programs failed to provide a reliable prediction of such reservoirs due to their high heterogeneity and the reactivity of the rock. Potentially, in-situ combustion (ISC) is considered effective in developing heavy oils in carbonate reservoirs. The combustion reactions between crude oil and heterogeneous rock matrices introduce additional complexity to the simulation process. Also, most of the laboratory experiments studying the reaction kinetics of the ISC process are performed on the crushed core. However, to minimize the risks, improve the control of the process, and overcome upscaling issues, physical simulation must be carried out under conditions as close to the reservoir as possible. Consolidated core material in combustion tube (CT) experiments is desirable for better simulating some reservoir conditions with synthetic packs and for the cases when actual preserved reservoir core material may be available. Studying the relative effects of porosity and packing properties (specific surface area, sand grain distribution, and cementation) on the fuel is essential to evaluating the process under actual field conditions. This work presents a set of medium-pressure CT (MPCT) tests on crushed and consolidated cores and analyzes the differences, limitations, and performances of both approaches. Two MPCT tests were performed to evaluate the ISC feasibility on the heavy-oil carbonate reservoir with an initial oil saturation level of 0.38 to 0.50. According to previously published experimental results, such oil saturation levels can help avoid oil banking. Both experiments were conducted at reservoir conditions to consider the phase behavior at elevated pressures and temperatures. The method used in this research allows approbation of the methodology of ISC tests using consolidated core at high pressure, ensuring pack and process integrity during the experiment. The influence of consolidated core caused by significantly lower porosity and more uniform porous media elements than those made with unconsolidated material on combustion performance was assessed. Valuable data for different variations of combustion experiments were generated. This work compared two tests and presented the combustion parameters for a stabilized combustion period, such as fuel and air requirements, recovery efficiency, front velocity, and composition of produced gases. The research intends to demonstrate the potential application problems and address issues that might arise during ISC application on target reservoirs, including the higher air flux required for lower porosity of consolidated core samples. The experimental results performed under conditions closest to reservoir conditions are essential for further predictions and affect the ISC performance during pilot tests.

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Experimental Evaluation Of In Situ Combustion In Naturally Consolidated Cores

Cited by 3 publications

References 0 publications

Chain Reactions Approach to the Initial Stages of Crude Oil Oxidation

Chain Reactions Approach to the Initial Stages of Crude Oil Oxidation

Design Parameters and Technique Evaluation of Combustion Processes from Tube Testing

Comparative Study of In-Situ Combustion Tests on Consolidated and Crushed Cores

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