Mao Romero | PUC-RJ - Academia.edu (original) (raw)
Papers by Mao Romero
Materials Processing, 2006
Ingeniería e Investigación, 2016
Computational tools for simulation of multiphase flow in oil pipelines are of great importance fo... more Computational tools for simulation of multiphase flow in oil pipelines are of great importance for the determination of the technical feasibility of the production in oilfields. The present article presents the mathematical and numerical modeling of the oil biphasic flow in a partially submerged onshore pipeline. The biphasic behavior of the heavy oil of 13,2 ºAPI is translated by the Dukler correlation. The oil's viscosity is regarded as dependent on the temperature and on the API density of the oil by means of the Hossain correlation. The pipeline, of 3,600 m and 4 inches (10.16 cm) in diameter, transports the oil from a collecting station to a storage center and consists of three sections. The first and third sections are above ground and are in contact with the external environment. The intermediate section is sitting on the river bed and is the critical part of the pipeline, once high heat losses are observed. The influence on the type of pipe insulation in the pressure and temperature gradients was analyzed with the aid of commercial 1D software Pipesim ®. The results, of this 1D and non-isothermal problem with prescribed outlet pressure, show that the use of isolation when appropriately designed in terms of material quality and thickness is of utmost importance to maintain the heat transfer at low levels, in order to ensure the movement of fluids in long sections without compromising the system operation.
SPE Annual Technical Conference and Exhibition, 2009
Flow of emulsion in porous media plays an important role in many enhanced oil recovery processes.... more Flow of emulsion in porous media plays an important role in many enhanced oil recovery processes. Drops may partially block pore passages leading to a better sweep of the reservoir. Despite all the efforts, the detailed mechanism of how emulsions flow through the pore space is not completely understood. Modeling the flow of emulsion in porous media is extremely challenging. In many situations the size of the dispersed phase drops is in the same order of magnitude of the pore throats. Therefore, in the pore scale the emulsion cannot be described as a single phase liquid with an effective viscosity. In this work we analyze the flow of emulsion in porous media by experiments and a capillary network model. The model is based on the flow rate-pressure drop relation of emulsion flow through constricted capillaries, which is a function of the capillary number of the flow, liquid properties and the ratio of drop to capillary throat diameter. The capillary network modeling was constructed in...
European Offshore Technology Conference and Exhibition, 1980
The presence of wax in crude oil can lead to the formation of wax deposits on the walls of pipeli... more The presence of wax in crude oil can lead to the formation of wax deposits on the walls of pipelines and as a consequence significant increases in pumping pressure caused mainly by an increase in the pipewall roughness. This can be particularly pronounced with the high cooling rates typical of submarine pipelines and is not restricted just to very waxy crudes. Using an extension of standard molecular diffusion theory the parameters influencing wax deposition rates are identified, and from simple laboratory tests on stabilized crude the rate of deposition in full scale pipelines can be predicted. Further, these principles and test methods can be applied to evaluate the effectiveness of the many available deposit-inhibiting additives under conditions appropriate to pipeline operations. INTRODUCTION Pipelines are widely used to transport crude oil. To ensure efficient use it is important to maintain their integrity and to minimise any flow restrictions. Water drop out in pipelines carr...
International Journal of Multiphase Flow, 2012
ABSTRACT We show that the mobility of an emulsion with drops larger than the porous throats is a ... more ABSTRACT We show that the mobility of an emulsion with drops larger than the porous throats is a strong function of the local capillary number; it falls as the interfacial forces become stronger (low capillary number). Emulsion drops have little effect on the fluid mobility at high capillary number. This flow behavior can be used as a selective mobility control mechanism driven by capillary forces. The flow rate and emulsion characteristics can be selected in such a way that fluid mobility near the injecting source remains high, allowing the emulsion to reach the location where the mobility control is needed. To prove the benefit of capillary-driven mobility control, we study the displacement of mineral oil by water and emulsion at two capillary numbers by measuring the volume of displaced fluid. Higher efficiency displacement due to high mobility of the displacing fluid only occurs at low capillary number.
Physical Review E, 2011
Transport of emulsions in porous media is relevant to several subsurface applications. Many enhan... more Transport of emulsions in porous media is relevant to several subsurface applications. Many enhanced oil recovery (EOR) processes lead to emulsion formation and as a result conformance originating in the flow of a dispersed phase may arise. In some EOR processes, emulsion is injected directly as a mobility control agent. Modeling the flow of emulsion in porous media is extremely challenging due to the complex nature of the associated flows and numerous interfaces. The descriptions based on effective viscosity are not valid when the drop size is of the same order of magnitude as the pore-throat characteristic length scale. An accurate model of emulsion flow through porous media should describe this local change in mobility. The available filtration models do not take into account the variation of the straining and capturing rates with the local capillary number. In this work, we present experiments of emulsion flow through sandstone cores of different permeability and a first step on a capillary network model that uses experimentally determined pore-level constitutive relationships between flow rate and pressure drop in constricted capillaries to obtain representative macroscopic flow behavior emerging from microscopic emulsion flow at the pore level. A parametric analysis is conducted to study the effect of the permeability and dispersed phase droplet size on the flow response to emulsion flooding in porous media. The network model predictions qualitatively describe the oil-water emulsion flow behavior observed in the experiments.
Crude oil is a complex mixture of hydrocarbons which consists of aromatics, paraffins, naphthenic... more Crude oil is a complex mixture of hydrocarbons which consists of aromatics, paraffins, naphthenics, resins asphaltenes, etc. When the temperature of crude oil is reduced, the heavy components, like paraffin, will precipitate and deposit on the pipe internal wall in the form of a wax-oil gel. The gel deposit consists of wax crystals that trap some amount of oil. As the temperature gets cooler, more wax will precipitate and the thickness of the wax gel will increase, causing gradual solidification of the crude and eventually the oil stop moving inside the offshore pipeline. Crude oil may not be able to be re-mobilized during re-startup. The effective diameter will be reduced with wax deposition, resulting in several problems, for example, higher pressure drop which means additional pumping energy costs, poor oil quality, use of chemical components like precipitation inhibitors or flowing facilitators, equipment failure, risk of leakage, clogging of the ducts and process equipment. Wax...
Journal of Petroleum Science and Engineering, 2013
ABSTRACT Single phase experiments were carried out in Berea sandstone to understand the behavior ... more ABSTRACT Single phase experiments were carried out in Berea sandstone to understand the behavior of the water-rock system and establish a baseline to interpret multiphase experiments. The water-rock reactions at microscopic level are reflected in the macroscopic scale by alteration in permeability in the rock and pH in the effluent. In our experiments we assume that the significant changes are solely a result of the alteration of the brine salinity since the composition of the brine and mineralogy of the core were held constant. Injection of brine with 1% salinity produced permanent permeability reduction due to fines release. Two phase experiments were carried out in undamaged and damaged Berea sandstone core. Comparison of single-phase and two-phase experiments results in undamaged Berea cores showed the same pressure and pH behavior when low salinity waterflooding is performed. Incremental oil production was observed in both undamaged and damaged core suggesting the mechanism of incremental production during low salinity injection is not solely related to fines migration.
Physical Review E, 2011
Transport of emulsions in porous media is relevant to several subsurface applications. Many enhan... more Transport of emulsions in porous media is relevant to several subsurface applications. Many enhanced oil recovery (EOR) processes lead to emulsion formation and as a result conformance originating in the flow of a dispersed phase may arise. In some EOR processes, emulsion is injected directly as a mobility control agent. Modeling the flow of emulsion in porous media is extremely challenging due to the complex nature of the associated flows and numerous interfaces. The descriptions based on effective viscosity are not valid when the drop size is of the same order of magnitude as the pore-throat characteristic length scale. An accurate model of emulsion flow through porous media should describe this local change in mobility. The available filtration models do not take into account the variation of the straining and capturing rates with the local capillary number. In this work, we present experiments of emulsion flow through sandstone cores of different permeability and a first step on a capillary network model that uses experimentally determined pore-level constitutive relationships between flow rate and pressure drop in constricted capillaries to obtain representative macroscopic flow behavior emerging from microscopic emulsion flow at the pore level. A parametric analysis is conducted to study the effect of the permeability and dispersed phase droplet size on the flow response to emulsion flooding in porous media. The network model predictions qualitatively describe the oil-water emulsion flow behavior observed in the experiments.
Materials Processing, 2006
Ingeniería e Investigación, 2016
Computational tools for simulation of multiphase flow in oil pipelines are of great importance fo... more Computational tools for simulation of multiphase flow in oil pipelines are of great importance for the determination of the technical feasibility of the production in oilfields. The present article presents the mathematical and numerical modeling of the oil biphasic flow in a partially submerged onshore pipeline. The biphasic behavior of the heavy oil of 13,2 ºAPI is translated by the Dukler correlation. The oil's viscosity is regarded as dependent on the temperature and on the API density of the oil by means of the Hossain correlation. The pipeline, of 3,600 m and 4 inches (10.16 cm) in diameter, transports the oil from a collecting station to a storage center and consists of three sections. The first and third sections are above ground and are in contact with the external environment. The intermediate section is sitting on the river bed and is the critical part of the pipeline, once high heat losses are observed. The influence on the type of pipe insulation in the pressure and temperature gradients was analyzed with the aid of commercial 1D software Pipesim ®. The results, of this 1D and non-isothermal problem with prescribed outlet pressure, show that the use of isolation when appropriately designed in terms of material quality and thickness is of utmost importance to maintain the heat transfer at low levels, in order to ensure the movement of fluids in long sections without compromising the system operation.
SPE Annual Technical Conference and Exhibition, 2009
Flow of emulsion in porous media plays an important role in many enhanced oil recovery processes.... more Flow of emulsion in porous media plays an important role in many enhanced oil recovery processes. Drops may partially block pore passages leading to a better sweep of the reservoir. Despite all the efforts, the detailed mechanism of how emulsions flow through the pore space is not completely understood. Modeling the flow of emulsion in porous media is extremely challenging. In many situations the size of the dispersed phase drops is in the same order of magnitude of the pore throats. Therefore, in the pore scale the emulsion cannot be described as a single phase liquid with an effective viscosity. In this work we analyze the flow of emulsion in porous media by experiments and a capillary network model. The model is based on the flow rate-pressure drop relation of emulsion flow through constricted capillaries, which is a function of the capillary number of the flow, liquid properties and the ratio of drop to capillary throat diameter. The capillary network modeling was constructed in...
European Offshore Technology Conference and Exhibition, 1980
The presence of wax in crude oil can lead to the formation of wax deposits on the walls of pipeli... more The presence of wax in crude oil can lead to the formation of wax deposits on the walls of pipelines and as a consequence significant increases in pumping pressure caused mainly by an increase in the pipewall roughness. This can be particularly pronounced with the high cooling rates typical of submarine pipelines and is not restricted just to very waxy crudes. Using an extension of standard molecular diffusion theory the parameters influencing wax deposition rates are identified, and from simple laboratory tests on stabilized crude the rate of deposition in full scale pipelines can be predicted. Further, these principles and test methods can be applied to evaluate the effectiveness of the many available deposit-inhibiting additives under conditions appropriate to pipeline operations. INTRODUCTION Pipelines are widely used to transport crude oil. To ensure efficient use it is important to maintain their integrity and to minimise any flow restrictions. Water drop out in pipelines carr...
International Journal of Multiphase Flow, 2012
ABSTRACT We show that the mobility of an emulsion with drops larger than the porous throats is a ... more ABSTRACT We show that the mobility of an emulsion with drops larger than the porous throats is a strong function of the local capillary number; it falls as the interfacial forces become stronger (low capillary number). Emulsion drops have little effect on the fluid mobility at high capillary number. This flow behavior can be used as a selective mobility control mechanism driven by capillary forces. The flow rate and emulsion characteristics can be selected in such a way that fluid mobility near the injecting source remains high, allowing the emulsion to reach the location where the mobility control is needed. To prove the benefit of capillary-driven mobility control, we study the displacement of mineral oil by water and emulsion at two capillary numbers by measuring the volume of displaced fluid. Higher efficiency displacement due to high mobility of the displacing fluid only occurs at low capillary number.
Physical Review E, 2011
Transport of emulsions in porous media is relevant to several subsurface applications. Many enhan... more Transport of emulsions in porous media is relevant to several subsurface applications. Many enhanced oil recovery (EOR) processes lead to emulsion formation and as a result conformance originating in the flow of a dispersed phase may arise. In some EOR processes, emulsion is injected directly as a mobility control agent. Modeling the flow of emulsion in porous media is extremely challenging due to the complex nature of the associated flows and numerous interfaces. The descriptions based on effective viscosity are not valid when the drop size is of the same order of magnitude as the pore-throat characteristic length scale. An accurate model of emulsion flow through porous media should describe this local change in mobility. The available filtration models do not take into account the variation of the straining and capturing rates with the local capillary number. In this work, we present experiments of emulsion flow through sandstone cores of different permeability and a first step on a capillary network model that uses experimentally determined pore-level constitutive relationships between flow rate and pressure drop in constricted capillaries to obtain representative macroscopic flow behavior emerging from microscopic emulsion flow at the pore level. A parametric analysis is conducted to study the effect of the permeability and dispersed phase droplet size on the flow response to emulsion flooding in porous media. The network model predictions qualitatively describe the oil-water emulsion flow behavior observed in the experiments.
Crude oil is a complex mixture of hydrocarbons which consists of aromatics, paraffins, naphthenic... more Crude oil is a complex mixture of hydrocarbons which consists of aromatics, paraffins, naphthenics, resins asphaltenes, etc. When the temperature of crude oil is reduced, the heavy components, like paraffin, will precipitate and deposit on the pipe internal wall in the form of a wax-oil gel. The gel deposit consists of wax crystals that trap some amount of oil. As the temperature gets cooler, more wax will precipitate and the thickness of the wax gel will increase, causing gradual solidification of the crude and eventually the oil stop moving inside the offshore pipeline. Crude oil may not be able to be re-mobilized during re-startup. The effective diameter will be reduced with wax deposition, resulting in several problems, for example, higher pressure drop which means additional pumping energy costs, poor oil quality, use of chemical components like precipitation inhibitors or flowing facilitators, equipment failure, risk of leakage, clogging of the ducts and process equipment. Wax...
Journal of Petroleum Science and Engineering, 2013
ABSTRACT Single phase experiments were carried out in Berea sandstone to understand the behavior ... more ABSTRACT Single phase experiments were carried out in Berea sandstone to understand the behavior of the water-rock system and establish a baseline to interpret multiphase experiments. The water-rock reactions at microscopic level are reflected in the macroscopic scale by alteration in permeability in the rock and pH in the effluent. In our experiments we assume that the significant changes are solely a result of the alteration of the brine salinity since the composition of the brine and mineralogy of the core were held constant. Injection of brine with 1% salinity produced permanent permeability reduction due to fines release. Two phase experiments were carried out in undamaged and damaged Berea sandstone core. Comparison of single-phase and two-phase experiments results in undamaged Berea cores showed the same pressure and pH behavior when low salinity waterflooding is performed. Incremental oil production was observed in both undamaged and damaged core suggesting the mechanism of incremental production during low salinity injection is not solely related to fines migration.
Physical Review E, 2011
Transport of emulsions in porous media is relevant to several subsurface applications. Many enhan... more Transport of emulsions in porous media is relevant to several subsurface applications. Many enhanced oil recovery (EOR) processes lead to emulsion formation and as a result conformance originating in the flow of a dispersed phase may arise. In some EOR processes, emulsion is injected directly as a mobility control agent. Modeling the flow of emulsion in porous media is extremely challenging due to the complex nature of the associated flows and numerous interfaces. The descriptions based on effective viscosity are not valid when the drop size is of the same order of magnitude as the pore-throat characteristic length scale. An accurate model of emulsion flow through porous media should describe this local change in mobility. The available filtration models do not take into account the variation of the straining and capturing rates with the local capillary number. In this work, we present experiments of emulsion flow through sandstone cores of different permeability and a first step on a capillary network model that uses experimentally determined pore-level constitutive relationships between flow rate and pressure drop in constricted capillaries to obtain representative macroscopic flow behavior emerging from microscopic emulsion flow at the pore level. A parametric analysis is conducted to study the effect of the permeability and dispersed phase droplet size on the flow response to emulsion flooding in porous media. The network model predictions qualitatively describe the oil-water emulsion flow behavior observed in the experiments.