Objective/Scope: Integrated asset modeling (IAM) offers the oil industry several benefits. The ne... more Objective/Scope: Integrated asset modeling (IAM) offers the oil industry several benefits. The next-generation reservoir simulators help achieve faster runtimes, insight into interaction between various components of a development, and can be used as an effective tool in detecting bottlenecks in a production system as well as a constant and more effective communication tool between various departments. IAM provides significant opportunities for optimization of very large or complex infrastructures and life-of-field analysis of production optimization scenarios.Simultaneous modeling of surface and subsurface components helps reduce time and enhances efficiency during the decision-making process which eliminates the requirement for tedious, time-consuming work and iterations between separate solutions of reservoir and surface networks. Beyond this convenience, this technology makes it possible to reach more robust results more quickly using surface-subsurface coupling. The objective of this study is to outline the advantages and the challenges in using next-generation simulators on simulation of multiple reservoirs in integrated asset management. Methods/Processes: Simultaneous simulation of multiple reservoirs adds another dimension of complexity to the process of integrated asset modeling. Several sub-reservoir models can be simulated simultaneously in large fields comprising sub-reservoirs with complex surface systems, which could otherwise become very tedious to handle. In this study, a next-generation reservoir simulator is coupled with an optimization and uncertainty tool that is used to optimize the net present value of the entire asset. Several constraints and bottlenecks in such a large system exist, all connected to one another. IAM proves useful in debottlenecking to increase efficiency of the thorough system. The strengths and difficulties associated with simultaneous simulation and optimization of multiple reservoirs are compared to the more conventional way of simulating the assets separately, thus illustrating the benefits of using next-generation reservoir simulators during optimization of multiple reservoirs. Results/Observations: The results show that simultaneous solution of the surface-subsurface coupling gives significantly faster results than that of a system that consists of separate solution of surface and subsurface. The speed difference becomes more significant when the number of reservoirs simulated is more than one. This study outlines the workflow in setting up the model, the CPU time for each component of the simulation, the explanation of each important item in this process to illustrate the
Objectives/Scope:: Since its accidental discovery in Venezuela during a steamflood procedure, and... more Objectives/Scope:: Since its accidental discovery in Venezuela during a steamflood procedure, and despite the high costs associated with using steam. CSS has been widely used throughout the world in heavy-oil reservoirs, especially in Alberta, California, and Venezuela. It has turned out that it is also important to understand the degree of impact of geomechanics as it is a key parameter in reservoirs with geomechanical response. This makes the optimization process more valuable in terms of the application of crucial operational constraints and parameters, such as injection rate, cycle size, cycle life, and well spacing, not only for the reservoir but also the wellbore, which are important for delivering steam to the subsurface while ensuring minimum heat loss along with reservoir integrity and permeability variation. Methods, Procedures, Process: The CSS recovery method is influenced by complex reservoir geologies, where a CSS well can penetrate multiple layers having significantly different properties, including permeability. It is important to have a solid understanding of the impact of multiple layers on recovery when using CSS, not only to help maximize recovery but also net-present value because of the high cost of steam generation. In this study, a commercial full-physics reservoir simulator is used to simulate the effect of multiple layers with varying permeabilities under different operating conditions. Results, Observations, Conclusions: CSS helps to increase recoveries up to 20 to 25% by means of certain mechanisms, including but not limited to viscosity reduction thermal expansion of oil, blocking removal, and gravity drainage. Although it is generally valid that higher steam qualities and shorter soak times provide higher recoveries, the main stages of cyclic steam stimulation (CSS)—injection, soaking, and production—should be carefully optimized because the efficiency of this technique is reduced after the first few cycles. The influence of geomechanics turns out to be a significant parameter in this process. Novel/Additive Information: The results and sensitivities are compared and discussed in light of a comprehensive literature review of CSS with different process optimization methods, including sequential CSS and cumulative average daily profit methods. The significance of all major parameters are outlined using tornado charts to serve as a practical example for optimization of similar future applications.
Started in the late 1800s in the US, water being relatively inexpensive and readily available in ... more Started in the late 1800s in the US, water being relatively inexpensive and readily available in large volumes and as being very effective at significantly increasing oil recovery, waterflooding has been the most common secondary recovery method applied throughout the world, contributing to pressure maintenance in the reservoir and displacing the oil phase. While there are several parameters that influence the performance of a waterflood, water quality is one of the important factors as it may cause scaling in the injection wells as well as some formation damage through chemical phenomena such as cation exchange in the reservoir resulting in decreased the recoveries. As waterfloods continue over decades, prevention of scale formation becomes a more significant factor that needs to be properly treated. The precipitation of inorganic scale is a major issue in injecting brines with a high concentration of divalent ions. The scaling tendency of water is highly correlated with the hardness of the injection water. Following corrosion, insoluble iron precipitates can cause damage in injection wells where precipitates can lead to severe reductions in well injectivity. Water needs to be treated in a proper way if the water contains high concentrations of calcium, magnesium or iron. In most waterflood applications, seawater needs to be used and this phenomenon is also an issue when injecting seawater into formations that contains brines with high salinity. In this study, a comprehensive analysis of this common problem is provided by investigating the significance of parameters affecting the severity of the scale through utilizing a seawater scale buildup model to be simulated using a commercial simulator along with an in-depth review of previous studies. Waterflooding Waterflooding is one of the most used seconday recovery technique throughout the world. The principal reason of water injection into reservoir is to increase the oil production rate thus the ultimate recovery. This is accomplished by the voidage replacement. The water is injected to increase the reservoir pressure to its original level and maintain it at that level. Also water displaces the oil from the pore spaces, however; the displacement efficiency depends on many factors like oil viscosity, rock characteristics etc.
Objectives/Scope: Coalbed methane (CBM) has become an important source of clean energy in the rec... more Objectives/Scope: Coalbed methane (CBM) has become an important source of clean energy in the recent decades worldwide including the US, China, Australia, India and Russia with more than 60 countries having different degrees of promising coal reserves. CBM reservoirs are distinguished from conventional reservoirs due to the major difference in the mechanism of gas storage and production of water. In CBM reservoirs, pores act as the major storage mechanism as gas is trapped and stored there and produced by means of dewatering and thus lowering the reservoir pressure. Free gas forms as the pressure is lowered leading to increased gas permeability of coal and thus increasing recovery. Microbial activity and thermal maturation of organic compounds are the main mechanisms of methane generation in lower-and-higher rank coals, respectively. Even though methane is an abundant and clean energy source, there are certain operational, technical and economic challenges involved in its production due its unique nature outlined above. Thus, a strong understanding of the parameters and uncertainties that influence the recovery is crucial. Methods, Procedures, Process: Due to the fact that the organic materials that make up coals generally have a stronger affinity for CO2 than for methane, CO2 is used as an enhanced recovery method to displace methane as an enhanced coalbed methane recovery (ECBM) method. While there is no current comprehensive optimization study on the effects of such factors, ECBM has a very significant role in the future of energy as it means more energy out of natural gas while eliminating the adverse effects of greenhouse gases. Results, Observations, Conclusions: In this study, a standard SPE reservoir simulation model is used to study the factors influencing the recovery in coal bed methane reservoirs by investigating the significance of parameters including but not limited to porosity, adsorption capacity, fracture permeability along with coal density and irreducible water saturation. Novel/Additive Information: The optimization results obtained by means of coupling a full-physics commercial numerical reservoir simulator with an optimization/uncertainty tool are presented outlining the different degrees of significance of these factors on production and ultimate recovery for better understanding of the phenomenon that will lead to more robust reservoir management decisions.
Reservoir management in fields with geomechanical issues such as subsidence and dilation due to i... more Reservoir management in fields with geomechanical issues such as subsidence and dilation due to injection and production activities is challenging where it is crucial to prevent well failures due to resulting shear or compaction stresses that might lead to serious losses owing to well and facility failures and impact success of production operations. A robust understanding of changes in reservoir parameters that influence subsurface recovery is as important to predict the adverse effects of compaction in the reservoir. The objective of this study is to investigate the effects of injection and production not only on compaction and dilation but also on reservoir fluid flow phenomenon including the significance of rock properties on flow due to changes in permeability in order to outline the significance of decision or control parameters of injection/production along with uncertainty parameters of reservoir rock. The results will provide useful in observing the significance of each parameter on production and recovery. In our study, a full-physics commercial numerical reservoir simulator has been utilized where it is coupled with an optimization and uncertainty tool to investigate the significance of decision parameters such as amount and rate of injection and production as well as the uncertainty parameters such as rock properties with different Young's Modulus. Different rock types are assigned in the geomechanics section due to different Young's modulus on each layer. Different constitutive models are assigned on rock layers. Linear elastic model and nonlinear elastic model are employed. Output stresses, subsidence and displacement vector are used to evaluate the influence of injection and production. Effect of production on compaction with decrease in permeability has been observed under different scenarios that include different operating conditions such as rates and different uncertainty parameters such as rock types with unique Young's modulus and permeability. The significance of each parameter is presented to provide a better understanding on reservoir management for reservoirs where geome-chanical stresses are crucial in decision making on operational constraints and design. Numerical reservoir simulation with geomechanics option is a convenient tool to predict not only the reservoir performance but also the reservoir stresses occurring due to injection and production. The reservoir model with geomechanics-dependent permeability provides a more realistic forecast for recovery compared to the models where geomechanics is ignored. The understanding of effect of injection and production on stresses generated in reservoir enables more optimum operation of wells to minimize such
Objective/Scope: Integrated asset modeling (IAM) offers the oil industry several benefits. The ne... more Objective/Scope: Integrated asset modeling (IAM) offers the oil industry several benefits. The next-generation reservoir simulators help achieve faster runtimes, insight into interaction between various components of a development, and can be used as an effective tool in detecting bottlenecks in a production system as well as a constant and more effective communication tool between various departments. IAM provides significant opportunities for optimization of very large or complex infrastructures and life-of-field analysis of production optimization scenarios.Simultaneous modeling of surface and subsurface components helps reduce time and enhances efficiency during the decision-making process which eliminates the requirement for tedious, time-consuming work and iterations between separate solutions of reservoir and surface networks. Beyond this convenience, this technology makes it possible to reach more robust results more quickly using surface-subsurface coupling. The objective of this study is to outline the advantages and the challenges in using next-generation simulators on simulation of multiple reservoirs in integrated asset management. Methods/Processes: Simultaneous simulation of multiple reservoirs adds another dimension of complexity to the process of integrated asset modeling. Several sub-reservoir models can be simulated simultaneously in large fields comprising sub-reservoirs with complex surface systems, which could otherwise become very tedious to handle. In this study, a next-generation reservoir simulator is coupled with an optimization and uncertainty tool that is used to optimize the net present value of the entire asset. Several constraints and bottlenecks in such a large system exist, all connected to one another. IAM proves useful in debottlenecking to increase efficiency of the thorough system. The strengths and difficulties associated with simultaneous simulation and optimization of multiple reservoirs are compared to the more conventional way of simulating the assets separately, thus illustrating the benefits of using next-generation reservoir simulators during optimization of multiple reservoirs. Results/Observations: The results show that simultaneous solution of the surface-subsurface coupling gives significantly faster results than that of a system that consists of separate solution of surface and subsurface. The speed difference becomes more significant when the number of reservoirs simulated is more than one. This study outlines the workflow in setting up the model, the CPU time for each component of the simulation, the explanation of each important item in this process to illustrate the
Objectives/Scope:: Since its accidental discovery in Venezuela during a steamflood procedure, and... more Objectives/Scope:: Since its accidental discovery in Venezuela during a steamflood procedure, and despite the high costs associated with using steam. CSS has been widely used throughout the world in heavy-oil reservoirs, especially in Alberta, California, and Venezuela. It has turned out that it is also important to understand the degree of impact of geomechanics as it is a key parameter in reservoirs with geomechanical response. This makes the optimization process more valuable in terms of the application of crucial operational constraints and parameters, such as injection rate, cycle size, cycle life, and well spacing, not only for the reservoir but also the wellbore, which are important for delivering steam to the subsurface while ensuring minimum heat loss along with reservoir integrity and permeability variation. Methods, Procedures, Process: The CSS recovery method is influenced by complex reservoir geologies, where a CSS well can penetrate multiple layers having significantly different properties, including permeability. It is important to have a solid understanding of the impact of multiple layers on recovery when using CSS, not only to help maximize recovery but also net-present value because of the high cost of steam generation. In this study, a commercial full-physics reservoir simulator is used to simulate the effect of multiple layers with varying permeabilities under different operating conditions. Results, Observations, Conclusions: CSS helps to increase recoveries up to 20 to 25% by means of certain mechanisms, including but not limited to viscosity reduction thermal expansion of oil, blocking removal, and gravity drainage. Although it is generally valid that higher steam qualities and shorter soak times provide higher recoveries, the main stages of cyclic steam stimulation (CSS)—injection, soaking, and production—should be carefully optimized because the efficiency of this technique is reduced after the first few cycles. The influence of geomechanics turns out to be a significant parameter in this process. Novel/Additive Information: The results and sensitivities are compared and discussed in light of a comprehensive literature review of CSS with different process optimization methods, including sequential CSS and cumulative average daily profit methods. The significance of all major parameters are outlined using tornado charts to serve as a practical example for optimization of similar future applications.
Started in the late 1800s in the US, water being relatively inexpensive and readily available in ... more Started in the late 1800s in the US, water being relatively inexpensive and readily available in large volumes and as being very effective at significantly increasing oil recovery, waterflooding has been the most common secondary recovery method applied throughout the world, contributing to pressure maintenance in the reservoir and displacing the oil phase. While there are several parameters that influence the performance of a waterflood, water quality is one of the important factors as it may cause scaling in the injection wells as well as some formation damage through chemical phenomena such as cation exchange in the reservoir resulting in decreased the recoveries. As waterfloods continue over decades, prevention of scale formation becomes a more significant factor that needs to be properly treated. The precipitation of inorganic scale is a major issue in injecting brines with a high concentration of divalent ions. The scaling tendency of water is highly correlated with the hardness of the injection water. Following corrosion, insoluble iron precipitates can cause damage in injection wells where precipitates can lead to severe reductions in well injectivity. Water needs to be treated in a proper way if the water contains high concentrations of calcium, magnesium or iron. In most waterflood applications, seawater needs to be used and this phenomenon is also an issue when injecting seawater into formations that contains brines with high salinity. In this study, a comprehensive analysis of this common problem is provided by investigating the significance of parameters affecting the severity of the scale through utilizing a seawater scale buildup model to be simulated using a commercial simulator along with an in-depth review of previous studies. Waterflooding Waterflooding is one of the most used seconday recovery technique throughout the world. The principal reason of water injection into reservoir is to increase the oil production rate thus the ultimate recovery. This is accomplished by the voidage replacement. The water is injected to increase the reservoir pressure to its original level and maintain it at that level. Also water displaces the oil from the pore spaces, however; the displacement efficiency depends on many factors like oil viscosity, rock characteristics etc.
Objectives/Scope: Coalbed methane (CBM) has become an important source of clean energy in the rec... more Objectives/Scope: Coalbed methane (CBM) has become an important source of clean energy in the recent decades worldwide including the US, China, Australia, India and Russia with more than 60 countries having different degrees of promising coal reserves. CBM reservoirs are distinguished from conventional reservoirs due to the major difference in the mechanism of gas storage and production of water. In CBM reservoirs, pores act as the major storage mechanism as gas is trapped and stored there and produced by means of dewatering and thus lowering the reservoir pressure. Free gas forms as the pressure is lowered leading to increased gas permeability of coal and thus increasing recovery. Microbial activity and thermal maturation of organic compounds are the main mechanisms of methane generation in lower-and-higher rank coals, respectively. Even though methane is an abundant and clean energy source, there are certain operational, technical and economic challenges involved in its production due its unique nature outlined above. Thus, a strong understanding of the parameters and uncertainties that influence the recovery is crucial. Methods, Procedures, Process: Due to the fact that the organic materials that make up coals generally have a stronger affinity for CO2 than for methane, CO2 is used as an enhanced recovery method to displace methane as an enhanced coalbed methane recovery (ECBM) method. While there is no current comprehensive optimization study on the effects of such factors, ECBM has a very significant role in the future of energy as it means more energy out of natural gas while eliminating the adverse effects of greenhouse gases. Results, Observations, Conclusions: In this study, a standard SPE reservoir simulation model is used to study the factors influencing the recovery in coal bed methane reservoirs by investigating the significance of parameters including but not limited to porosity, adsorption capacity, fracture permeability along with coal density and irreducible water saturation. Novel/Additive Information: The optimization results obtained by means of coupling a full-physics commercial numerical reservoir simulator with an optimization/uncertainty tool are presented outlining the different degrees of significance of these factors on production and ultimate recovery for better understanding of the phenomenon that will lead to more robust reservoir management decisions.
Reservoir management in fields with geomechanical issues such as subsidence and dilation due to i... more Reservoir management in fields with geomechanical issues such as subsidence and dilation due to injection and production activities is challenging where it is crucial to prevent well failures due to resulting shear or compaction stresses that might lead to serious losses owing to well and facility failures and impact success of production operations. A robust understanding of changes in reservoir parameters that influence subsurface recovery is as important to predict the adverse effects of compaction in the reservoir. The objective of this study is to investigate the effects of injection and production not only on compaction and dilation but also on reservoir fluid flow phenomenon including the significance of rock properties on flow due to changes in permeability in order to outline the significance of decision or control parameters of injection/production along with uncertainty parameters of reservoir rock. The results will provide useful in observing the significance of each parameter on production and recovery. In our study, a full-physics commercial numerical reservoir simulator has been utilized where it is coupled with an optimization and uncertainty tool to investigate the significance of decision parameters such as amount and rate of injection and production as well as the uncertainty parameters such as rock properties with different Young's Modulus. Different rock types are assigned in the geomechanics section due to different Young's modulus on each layer. Different constitutive models are assigned on rock layers. Linear elastic model and nonlinear elastic model are employed. Output stresses, subsidence and displacement vector are used to evaluate the influence of injection and production. Effect of production on compaction with decrease in permeability has been observed under different scenarios that include different operating conditions such as rates and different uncertainty parameters such as rock types with unique Young's modulus and permeability. The significance of each parameter is presented to provide a better understanding on reservoir management for reservoirs where geome-chanical stresses are crucial in decision making on operational constraints and design. Numerical reservoir simulation with geomechanics option is a convenient tool to predict not only the reservoir performance but also the reservoir stresses occurring due to injection and production. The reservoir model with geomechanics-dependent permeability provides a more realistic forecast for recovery compared to the models where geomechanics is ignored. The understanding of effect of injection and production on stresses generated in reservoir enables more optimum operation of wells to minimize such
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