3 research outputs found
Mec谩nica del desplazamiento y estabilidad del petr贸leo espumoso durante la recuperaci贸n secundaria de petr贸leo pesado usando metano y aire
A pesar de que se llevaron a cabo muchas investigaciones experimentales sobre el flujo de petr贸leo espumoso, los fundamentos te贸ricos de su desempe帽o a煤n no son lo suficientemente convincentes, y los mecanismos para los procesos din谩micos y la estabilidad a煤n no se comprenden completamente. Con el fin de desarrollar una comprensi贸n mecanicista del flujo de petr贸leo espumoso en un medio poroso, se consideraron experimentos de laboratorio bajo dos escenarios de
inyecci贸n utilizando metano y aire como gases de inyecci贸n. Se realizaron experimentos de
inyecci贸n en un esquema CSI de un solo pozo para comprender la generaci贸n de petr贸leo
espumoso en reservorios post-CHOPS. Se consider贸 que el esquema CSI de m煤ltiples pozos para
comprender la generaci贸n de petr贸leo espumoso en reservorios delgados de petr贸leo pesado. Para
ambos arreglos, se realizaron diferentes estrategias de inyecci贸n, tales como inyecci贸n alterna e inyecci贸n simult谩nea de gas. Se ha observado que el uso del aire ahorra el uso de metano hasta un 26 % y un 51 % en esquemas de inyecci贸n de un solo pozo y de pozos m煤ltiple, respectivamente.Heavy oil and extra-heavy oil (natural bitumen and oil sands) resources represent 70% of the global petroleum reserves and are mostly found in shallow reservoirs with thin pay zones formed by unconsolidated sands. Thermal recovery methods are recognized for being the most efficient; yet, these methods face environmental challenges due to the high emissions of carbon dioxide generated by high energy demands, leading to high operational costs. Therefore, non-thermal recovery methods have attracted special attention from both industry and academia. Foamy oil is the terminology commonly accepted to describe an atypical behavior associated with heavy oil flow formed as a response to pressure depletion. The cyclic solvent injection (CSI) technology is a solvent-based non-thermal process that has gained interest and is considered as an effective technique for increasing the recovery factor either as a follow-up process to the cold heavy oil production with sand (CHOPS) or for thin heavy oil reservoirs. Notwithstanding that many experimental investigations on foamy oil flow were carried out, theoretical foundations of its performance are still not convincing enough, and the mechanisms for the dynamic processes and stability continue to not be fully understood. In order to develop a mechanistic understanding of foamy oil flow in a porous medium, laboratory experiments under two different well arrangement scenarios were considered, single-well and multi-well injection schemes, using methane and air as the injection gasses. Single-well CSI scheme injection experiments were performed in order to understand, in a more representative manner, the foamy oil generation by injecting gas externally to post-CHOPS reservoirs. The multi-well CSI scheme was considered to be applied in thin heavy oil reservoirs, and post-CHOPS reservoirs. For both arrangements, different injection strategies were performed, based on alternating gas injection and simultaneous gas injection. It was observed that on a single-well injection scheme, injecting a mixture of air and methane simultaneously can help to obtain larger recovery factors per cycle than when using methane alone. On a multi-well injection scheme, it has been observed that an alternating gas injection strategy has a better performance than the simultaneous injection. Using air has been observed to save methane usage up to 26% and 51% in single-well and multi-well injection schemes, respectively. Furthermore, in order to study the efficiency of using methane, air, and their mixture to generate stable foamy oils, observational experiments were performed by means of macroscopic (naked eye) and microscopic visualization which was interpreted through foamy oil stability parameters such as time of foamability and collapse, number of gas bubbles, gas bubbles distribution, and maximum bubble size. Using a mixture of air and methane has been observed not only to expand the volume of oil by 2.5 (volume expansion caused by methane has been found to be as high as 3.0) but also to delay the defoaming process.Canad谩. University of Alberta : Thesis-Based Master's Recruitment ScholarshipTesi
Negligible Forchheimer effect for a maximum gas flow rate in a gas condensate reservoir
In this paper the optimal gas flow rate in a retrograde gas condensate reservoir has been calculated in order to minimize retrograde condensation, maximizing the slip velocity, due to the positive coupling effect; and minimizing the pressure drawdown, due to the Forchheimer effect (non-Darcy effect, inertial effect). Non-Darcy behavior has been thoroughly described because of its importance for describing additional pressure drawdown (more than expected by Darcy equation) in fluid flow in porous media, in situations where high velocity occurs. The coupling effect explains the increment of the gas-condensate relative permeability with increasing velocity and decreasing the interfacial tension. The Forchheimer equation has been used to calculate the bottom-hole flowing pressure for different gas flow rates. Because of the second term in the Forchheimer equation, which is function of the square of the superficial velocity of the fluid, this obtained value is less than the bottom-hole flowing pressure obtained from Darcy equation. This is important because a higher quantity of condensate liquids is obtained, which reduces the relative permeability, and as a result, the gas flow rate decreases due to this effect. For those different gas flow rates, the optimal gas flow rate, where the bottom-hole flowing pressure is acceptable, has been found. The novelty of the present work, is to present the optimal point where the gas flow rate is maximum, in which the non-Darcy effect is negligible.En el presente trabajo se calcula el caudal 贸ptimo de gas de un yacimiento de gas condensado retr贸grado, con el objetivo de reducir la condensacion retr贸grada, maximizando la velocidad de arrastre debido al efecto coupling y minimizando la ca铆da de presi贸n debido al efecto Forchheimer (efecto no-Darcy, efecto inircial). El comportamiento inercial ha sido estudiado ampliamente debido a su importancia en describir la caida de presi贸n adicional (m谩s de la esperada de acuerdo a la ecuaci贸n de Darcy) en el flujo de fluidos en medios porosos, en situaciones de gran velocidad. El efecto de acoplamiento, explica el incremento de la permeabilidad relativa de gas condensado al incrementar la velocidad y disminuir la tensi贸n interfacial. La ecuaci贸n de Forchheimer se utiliz贸 para calcular la presi贸n de fondo fluyente a diferentes caudales. Debido al segundo t茅rmino en la ecuaci贸n de Forchheimer, la cual es funci贸n del cuadrado de la velocidad superficial del fluido, este valor obtenido resulta siendo menor a la presi贸n de fondo fluyente obtenida mediante la ecuaci贸n de Darcy. Esto es importante pues se acumula una cantidad mayor de l铆quidos, lo cual reduce la permeabilidad relativa, y como consecuencia, el caudal de gas disminuye. Para los caudales de gas propuestos, se encuentra el caudal de gas 贸ptimo, la cual es aquella donde la presi贸n de fondo fluyente es aceptable. La novedad del presente trabajo, es la presentaci贸n de un punto 贸ptimo, en el cual el caudal de gas es m谩ximo, para el cual el efecto inercial es despreciable en comparaci贸n con el efecto coupling
Negligible Forchheimer effect for a maximum gas flow rate in a gas condensate reservoir
En el presente trabajo se calcula el caudal 贸ptimo de gas de un yacimiento de gas condensado retr贸grado, con el objetivo de reducir la condensacion retr贸grada, maximizando la velocidad de arrastre debido al efecto coupling y minimizando la ca铆da de presi贸n debido al efecto Forchheimer (efecto no-Darcy, efecto inircial). El comportamiento inercial ha sido estudiado ampliamente debido a su importancia en describir la caida de presi贸n adicional (m谩s de la esperada de acuerdo a la ecuaci贸n de Darcy) en el flujo de fluidos en medios porosos, en situaciones de gran velocidad. El efecto de acoplamiento, explica el incremento de la permeabilidad relativa de gas condensado al incrementar la velocidad y disminuir la tensi贸n interfacial. La ecuaci贸n de Forchheimer se utiliz贸 para calcular la presi贸n de fondo fluyente a diferentes caudales. Debido al segundo t茅rmino en la ecuaci贸n de Forchheimer, la cual es funci贸n del cuadrado de la velocidad superficial del fluido, este valor obtenido resulta siendo menor a la presi贸n de fondo fluyente obtenida mediante la ecuaci贸n de Darcy. Esto es importante pues se acumula una cantidad mayor de l铆quidos, lo cual reduce la permeabilidad relativa, y como consecuencia, el caudal de gas disminuye. Para los caudales de gas propuestos, se encuentra el caudal de gas 贸ptimo, la cual es aquella donde la presi贸n de fondo fluyente es aceptable. La novedad del presente trabajo, es la presentaci贸n de un punto 贸ptimo, en el cual el caudal de gas es m谩ximo, para el cual el efecto inercial es despreciable en comparaci贸n con el efecto coupling.In this paper the optimal gas flow rate in a retrograde gas condensate reservoir has been calculated in order to minimize retrograde condensation, maximizing the slip velocity, due to the positive coupling effect; and minimizing the pressure drawdown, due to the Forchheimer effect (non-Darcy effect, inertial effect). Non-Darcy behavior has been thoroughly described because of its importance for describing additional pressure drawdown (more than expected by Darcy equation) in fluid flow in porous media, in situations where high velocity occurs. The coupling effect explains the increment of the gas-condensate relative permeability with increasing velocity and decreasing the interfacial tension. The Forchheimer equation has been used to calculate the bottom-hole flowing pressure for different gas flow rates. Because of the second term in the Forchheimer equation, which is function of the square of the superficial velocity of the fluid, this obtained value is less than the bottom-hole flowing pressure obtained from Darcy equation. This is important because a higher quantity of condensate liquids is obtained, which reduces the relative permeability, and as a result, the gas flow rate decreases due to this effect. For those different gas flow rates, the optimal gas flow rate, where the bottom-hole flowing pressure is acceptable, has been found. The novelty of the present work, is to present the optimal point where the gas flow rate is maximum, in which the non-Darcy effect is negligible