In this work, the catalytic aquathermolysis process of a Colombian heavy crude oil was studied. Reactivity tests were conducted in a microbatch reactor at 270 °C and saturation pressure of 5.5 MPa, during 66 h, using iron and molybdenum naphthenates in concentrations of 50−300 ppm as catalysts. The use of these catalysts reduced the gas yield from 1% to 4.2% w/w, the viscosity from 10% to 52.3% with iron naphthenate, and from 11.6% to 31.4% with molybdenum naphthenate. Crudes subjected to catalytic aquathermolysis increased their API gravity from 1.1 to 2.5 and 0.5 to 1.8 units, showing a significant decrease in complex fractions with boiling points above 340 °C and conversions in the order of 7% and 8% with respect to the precursors of molybdenum and iron naphthenates. Unlike other studies, the changes in the physical properties were correlated with changes in the chemical structure by ATR-FTIR spectroscopy. The average molecular parameters showed that the greatest differences with respect to the base crude oil were the length of the alkyl chains, the aromaticity, and the sulfurization. Results indicate different characteristics from the catalysts being studied, with iron naphthenate yielding better favorable effects in the change of the physicochemical properties of the improved crude oils. The experimental methodology proposed in this work indicates that the catalytic aquathermolysis process is a recovery method that allows for improving the properties of the crude oils, under reservoir conditions, due to the formation of products of smaller size and molecular weight.

*a quien debe dirigirse la correspondencia RESUMEN el comportamiento de diferentes modelos de isotermas de adsorción aplicados a los datos experimentales obtenidos por Gasparik et al. (2012) en una prueba de adsorción de metano, fue modelado y analizado, con el fi n de determinar el que mejor representa los datos experimentales. entre los modelos utilizados se encuentran algunos de dos parámetros como Langmuir, temkin y freundlich, otros de tres parámetros como Langmuir, DubininRadushkevich, Toth y Sips; de cuatro parámetros como Dubinin-Astakhov y Fritz-Schlunder y fi nalmente el modelo de cinco parámetros propuesto por fritz-schlunder. según los resultados obtenidos, los modelos presentaron mejor ajuste a medida que empleaban mayor número de parámetros en sus ecuaciones.Posteriormente se calculó la capacidad de almacenamiento total de gas para una formación hipotética con algunos datos de la formación Posidonea empleando el método propuesto por Ambrose et al (2010), el cual se modifi có reemplazando el término que tiene en cuenta el gas adsorbido con los modelos mencionados anteriormente, a fi n de determinar su infl uencia en las estimaciones de volumen de gas libre y de gas adsorbido. Con los modelos que presentaron un menor porcentaje de error, se obtuvieron datos más conservadores en el cálculo del gas adsorbido y de gas total, lo cual indica la importancia de la adecuada selección del modelo para el cálculo de reservas, dado que conlleva alto impacto técnico y económico.Palabras clave: shale, gas, yacimiento, isotermas, adsorción. Application of adsorption isotherm models of methane on a shale sample and their impact on reserves estimation ABSTRACTSeveral adsorption isotherm models were analyzed for the purpose of fi tting the experimental data published by Gasparik et al. (2012) obtained in a methane adsorption experiment on a shale sample from the Posidonea formation in the netherlands. the following are the ten models used in this study; some of them consist of two parameters such as Langmuir, temkin and freundlich, the three parameter models: Langmuir, DubininRadushkevich, Toth and Sips, four parameters: Dubinin-Astakhov and Fritz-Schlunder and the fi ve-parameter Fritz Schlunder correlation. The results show a better fi t to the experimental data for those models with the highest number of parameters.

An efficient way to increase oil production in heavy oil reservoirs is by the In Situ Combustion (ISC) process implementation. Part of the oil in place is oxidized, generating heat that increases mobility by reducing oil viscosity. The increase in oil production is associated with displacement mechanisms such as flue gas flooding, steam drive, viscosity reduction by oil swelling and temperature increase, among others. However, not all reservoirs are suitable for an ISC process. Therefore, prior to the implementation of an ISC project, the reservoir properties and reactive characteristics of oil should be evaluated. The isoconversional principle is a technique to obtain information about oil oxidation characteristics, using the kinetic of the oil oxidation/combustion reactions. The isoconversional methods obtain the kinetic from different Ramped Temperature Oxidation (RTO) tests, usually three to five; this technique provides direct information of the effective activation energy. In addition, the technique can be used as a screening tool to identify good candidates to an ISC process and allow recognition of the number of dominant reactions to model the process in numerical simulators. This paper presents the results obtained after applying the isoconversional principle in a Colombian heavy oil. Furthermore, a reaction scheme to model the process in a commercial numerical simulator is proposed. The reaction scheme was validated by matching the experimental results in a numerical thermal simulator.

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Durante la aplicación de la técnica de recobro mejorado del petróleo denominada combustión in situ, gran parte del calor generado durante la combustión se almacena en la arena calcinada detrás del frente de combustión y no se utiliza para el desplazamiento del aceite. La capacidad calorífica del aire seco es baja y el aire inyectado no puede transferir calor desde la matriz de la arena tan rápidamente como se genera. El agua por otra parte puede absorber y transportar el calor mucho más eficientemente que el aire. Si el aire se inyecta junto con el agua (combustión húmeda), el calor almacenado puede ser recuperado y transportado hacia adelante.Para el presente estudio se desarrolló el modelo base de simulación numérica de la prueba de tubo de combustión húmeda realizada a un crudo colombiano, el simulador STARS de la compañía CMG. Para el desarrollo del mismo, se planteó un modelo cinético que describe el comportamiento oxidativo del crudo de estudio. Posteriormente, se realizó el ajuste histórico del modelo de simulación y se compararon los resultados numéricos con los resultados del modelo físico. Finalizado el modelo de simulación, se procedió a evaluar el efecto del agua sobre los parámetros de desempeño del modelo de la prueba de tubo de combustión húmeda, para lo cual se realizó un análisis de sensibilidad a la tasa de inyección de agua y se analizó su impacto sobre cada uno de los parámetros de desempeño.Palabras clave: recobro mejorado del petróleo, combustión in situ, modelo de simulación, prueba de tubo de combustión, parámetros de desempeño. Wet in situ combustion: alternative for enhanced oil recovery in colombia ABSTRACTDuring the application of the enhanced oil recovery technique called in situ combustion, a great amount of the heat generated during combustion is stored in the burned sand behind the combustion front and is not used for oil displacement. The air heat capacity is low and the injected air can't transfer heat from the sand matrix as rapidly as is generated. Water, on the other hand, can absorb and transport heat much more efficiently than air. If air is injected with water, the heat stored sand can be recovered and transported forward.For the present research it was developed the numerical simulation model of the wet combustion tube test made to Colombian crude by the STARS simulator of the CMG company. For the development of the model, it was proposed a kinetic model that describes the oxidative behavior of the studied crude.Subsequently, it was made the history matching of the simulation model and were compared the numerical results with the results of the physical model. Finalized the simulation model, it was evaluated the effect of water on the performance parameters of the tube test model of wet combustion, for which it was made a sensitivity analysis to the water injection rate and it was analyzed its impact on each performance parameter.