54 research outputs found
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Experimental Investigation and High Resolution Simulator of In-Situ Combustion Processes
Accurate simulation of in-situ combustion processes is computationally very challenging because the spatial and temporal scales over which the combustion process takes place are very small. In this first quarterly report of our DoE funded research, we discuss the design of a new simulation tool based on an efficient Cartesian Adaptive Mesh Refinement technique that allows much higher grid densities to be used near typical fronts than current simulators. The formulation presented here for a first one-dimensional simulator will serve as the foundation for the development of a three-dimensional simulator that can handle realistic permeability heterogeneity. The development of the simulation tool will be supported by extensive laboratory experiments conducted to provide validation data, and to study effective variants of the combustion process. The preliminary investigation reported here shows how metallic salt additives can promote and sustain combustion by enhancing the oxidation and cracking of hydrocarbons
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Experimental Investigation and High Resolution Simulator of in-Situ Combustion Processes Quarterly Report
Accurate simulation of in-situ combustion processes is computationally very challenging because the spatial and temporal scales over which the combustion process takes place are very small. In this fifth quarterly report of our DoE funded research, we continue the discussion of the design of a new simulation tool based on an efficient Cartesian Adaptive Mesh Refinement technique that allows much higher grid densities to be used near typical fronts than current simulators. We have now developed an appropriate upscaling technique for our grids, based on the local-global upscaling approach. We show preliminary results on two-dimensional test cases. On the experimental side, we continued experiments to measure the rates and kinetics of combustion in the presence and absence of metallic additives. In this quarter, we developed a better understanding of the cation replacing power of the various additives that affect combustion performance positively, and obtained a preliminary reactivity series. We also resumed our experimental investigation into the cyclic solvent-combustion process using crude oil from the Hamaca Region of Venezuela. Various measurements were made including oxygen consumption as a function of temperature. Preliminary results show that the temperatures for the onset of combustion are a function of the solvent injected
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Experimental Investigation and High Resolution Simulator of In-Situ Combustion Processes Quarterly Report
Accurate simulation of in-situ combustion processes is computationally very challenging because the spatial and temporal scales over which the combustion process takes place are very small. In this first quarterly report of our DoE funded research, we discuss the design of a new simulation tool based on an efficient Cartesian Adaptive Mesh Refinement technique that allows much higher grid densities to be used near typical fronts than current simulators. The formulation presented here for a first one-dimensional simulator will serve as the foundation for the development of a three-dimensional simulator that can handle realistic permeability heterogeneity. The development of the simulation tool will be supported by extensive laboratory experiments conducted to provide validation data, and to study effective variants of the combustion process. The preliminary investigation reported here shows how metallic salt additives can promote and sustain combustion by enhancing the oxidation and cracking of hydrocarbons
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Heavy and Thermal Oil Recovery Production Mechanisms Progress Report
The Stanford University Petroleum Research Institute (SUPRI-A) conducts a broad spectrum of research intended to help improve the recovery efficiency from difficult to produce reservoirs including heavy oil and fractured low permeability systems. Our scope of work is relevant across near-, mid-, and long-term time frames. The primary functions of the group are to conduct direction-setting research, transfer research results to industry, and educate and train students for careers in industry. Presently, research in SUPRI-A is divided into 5 main project areas. These projects and their goals include: (1) Multiphase flow and rock properties--to develop better understanding of the physics of displacement in porous media through experiment and theory. This category includes work on imbibition, flow in fractured media, and the effect of temperature on relative permeability and capillary pressure. (2) Hot fluid injection--to improve the application of nonconventional wells for enhanced oil recovery and elucidate the mechanisms of steamdrive in low permeability, fractured porous media. (3) Mechanisms of primary heavy oil recovery--to develop a mechanistic understanding of so-called ''foamy oil'' and its associated physical chemistry. (4) In-situ combustion--to evaluate the effect of different reservoir parameters on the insitu combustion process. (5) Reservoir definition--to develop and improve techniques for evaluating formation properties from production information. What follows is a report on activities for the past year. Significant progress was made in all areas
Kinetics Oxidation of Heavy Oil. 2. Application of Genetic Algorithm for Evaluation of Kinetic Parameters
In-situ combustion (ISC) is the process of injecting air into oil reservoirs to oxidize part of the crude-oil and has been utilized for both light and heavy oil. The viscosity of the remaining crude-oil is reduced by the significant heat generated from combustion reactions, that contributes to enhanced oil recovery. In [give citation full out], we developed a new method to interpret Ramped Temperature Oxidation (RTO) experiments using a reactor model based on a compositional and full equation of state approach. In this work, we use this RTO reactor model coupled with an optimization tool in order to determine the optimal kinetic parameters for an extra heavy oil reservoir. Kinetic parameters are commonly determined using analytical methods and limited data. Typically only one type of observational data, for example oxygen consumption, is used from one experiment. Here, we use two series of experiments data, namely CO2 and O2 concentrations and a multi objective approach to obtain kinetic parameters for the different combustion reactions. We obtain finally a set of possible kinetic schemes, accouting for all mechanisms like reactions, phase changes and transport processes
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Heavy and Thermal Oil Recovery Production Mechanisms Progress Report
This technical progress report describes work performed from January 1 through March 31, 2003 for the project ''Heavy and Thermal Oil Recovery Production Mechanisms,'' DE-FC26-00BC15311. In this project, a broad spectrum of research is undertaken related to thermal and heavy-oil recovery. The research tools and techniques span from pore-level imaging of multiphase fluid flow to definition of reservoir-scale features through streamline-based history matching techniques. During this period, previous analysis of experimental data regarding multidimensional imbibition to obtain shape factors appropriate for dual-porosity simulation was verified by comparison among analytic, dual-porosity simulation, and fine-grid simulation. We continued to study the mechanisms by which oil is produced from fractured porous media at high pressure and high temperature. Temperature has a beneficial effect on recovery and reduces residual oil saturation. A new experiment was conducted on diatomite core. Significantly, we show that elevated temperature induces fines release in sandstone cores and this behavior may be linked to wettability. Our work in the area of primary production of heavy oil continues with field cores and crude oil. On the topic of reservoir definition, work continued on developing techniques that integrate production history into reservoir models using streamline-based properties
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Heavy and Thermal Oil Recovery Production Mechanisms Progress Report
This technical progress report describes work performed from April 1 through June 30, 2002, for the project ''Heavy and Thermal Oil Recovery Production Mechanisms.'' We investigate a broad spectrum of topics related to thermal and heavy-oil recovery. Significant results were obtained in the areas of multiphase flow and rock properties, hot-fluid injection, improved primary heavy oil recovery, and reservoir definition. The research tools and techniques used are varied and span from pore-level imaging of multiphase fluid flow to definition of reservoir-scale features through streamline-based history-matching techniques. Briefly, experiments were conducted to image at the pore level matrix-to-fracture production of oil from a fractured porous medium. This project is ongoing. A simulation studied was completed in the area of recovery processes during steam injection into fractured porous media. We continued to study experimentally heavy-oil production mechanisms from relatively low permeability rocks under conditions of high pressure and high temperature. High temperature significantly increased oil recovery rate and decreased residual oil saturation. Also in the area of imaging production processes in laboratory-scale cores, we use CT to study the process of gas-phase formation during solution gas drive in viscous oils. Results from recent experiments are reported here. Finally, a project was completed that uses the producing water-oil ratio to define reservoir heterogeneity and integrate production history into a reservoir model using streamline properties
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Heavy and Thermal Oil Recovery Production Mechanisms Progress Report
This technical progress report describes work performed from October 1 through December 31, 2002 , for the project ''Heavy and Thermal Oil Recovery Production Mechanisms.'' In this project, a broad spectrum of research is undertaken related to thermal and heavy-oil recovery. The research tools and techniques used are varied and span from pore-level imaging of multiphase fluid flow to definition of reservoir-scale features through streamline-based history-matching techniques. During this period, experimental data regarding multidimensional imbibition was analyzed to obtain shape factors appropriate for dual-porosity simulation. It is shown that the usual assumption of constant, time-independent shape factors is incorrect. In other work, we continued to study the mechanisms by which oil is produced from fractured media at high pressure and high temperature. High temperature significantly increased the apparent wettability and affected water relative permeability of cores used in previous experiments. A phenomenological and mechanistic cause for this behavior is sought. Our work in the area of primary production of heavy oil continues with field cores and crude oil. On the topic of reservoir definition, work continued on developing techniques that integrate production history into reservoir models using streamline-based properties
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An Analytical Model for Simulating Heavy-Oil Recovery by Cyclic Steam Injection Using Horizontal Wells, SUPRI TR-118
In this investigation, existing analytical models for cyclic steam injection and oil recovery are reviewed and a new model is proposed that is applicable to horizontal wells. A new flow equation is developed for oil production during cyclic steaming of horizontal wells. The model accounts for the gravity-drainage of oil along the steam-oil interface and through the steam zone. Oil viscosity, effective permeability, geometry of the heated zone, porosity, mobile oil saturation, and thermal diffusivity of the reservoir influence the flow rate of oil in the model. The change in reservoir temperature with time is also modeled, and it results in the expected decline in oil production rate during the production cycle as the reservoir cools. Wherever appropriate, correlations and incorporated to minimize data requirements. A limited comparison to numerical simulation results agrees well, indicating that essential physics are successfully captured. Cyclic steaming appears to be a systematic met hod for heating a cold reservoir provided that a relatively uniform distribution of steam is obtained along the horizontal well during injection. A sensitivity analysis shows that the process is robust over the range of expected physical parameters
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A Streamline Approach for History-Matching Production Data
This study proposes and develops a streamline approach for inferring field-scale effective permeability distributions based on dynamic production data including producer water-cut curve, well pressures, and rates. The streamline-based inverse approach simplifies the history-matching process significantly. The basic idea is to relate the water-cut curve at a producer to the water breakthrough of individual streamlines. By adjusting the effective permeability along streamlines, the breakthrough time of each streamline is found that reproduces the reference producer fractional-flow curve. Then the permeability modification along each streamline is mapped onto cells of the simulation grid. Modifying effective permeability at the streamline level greatly reduces the size of the inverse problem compared to modifications at the grid-block level. The approach outlined here is relatively direct and rapid. Limitations include that the forward flow problem must be solvable with streamlines, streamline locations do not evolve radically during displacement, no new wells are included, and relatively noise-free production data is available. It works well for reservoirs where heterogeneity determines flow patterns. Example cases illustrate computational efficiency, generality, and robustness of the proposed procedure. Advantages and limitations of this work, and the scope of future study, are also discussed
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