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Collaborating Authors
Results
A Study of the Impact of Permeability Barriers on Steam-Solvent Coinjection Using a Large-Scale Physical Model
Sheng, Kai (The University of Texas at Austin) | Okuno, Ryosuke (The University of Texas at Austin) | Al-Gawfi, Abdullah (Saskatchewan Research Council) | Nakutnyy, Petro (Saskatchewan Research Council)
Abstract This paper presents a solvent-assisted steam-assisted gravity drainage (SA-SAGD) experiment using condensate in a large physical model. The main objective of this research was to study the impact of permeability barriers on the in-situ thermal/compositional flow and the produced bitumen properties in SA-SAGD using condensate. A pressure vessel of 0.425 m in diameter and 1.2 m in length contained unconsolidated sands and two horizontal shale plates as permeability barriers. The two shale plates were placed at different elevations above the injection well and horizontally staggered so that they could make the main hydraulic paths tortuous during the experiment. The sandpack had a porosity of 0.34 and a permeability of 5.6 D, and it was initially saturated with 95% Athabasca bitumen and 5% deionized water. After 24 hours of preheating, SA-SAGD with 2.8 mol% condensate was performed at 35 cm/min (cold-water equivalent) at 3500 kPa for 4 days. The production, injection, and temperature distribution were recorded. Produced oil samples were analyzed for density and asphaltene content. The sandpack was excavated after the experiment to analyze the oil saturation and asphaltene content in the remaining oil at different locations. Results were compared with the previous SAGD and SA-SAGD experiments using the same physical model with a homogeneous sandpack. Results showed that SA-SAGD was efficient in the presence of permeability barriers with a cumulative steam-to-oil ratio (SOR) that was two to three times smaller than that ofthe homogeneous SAGD case. Temperature data indicated that a steam chamber vertically expanded from the lower part to the upper part through tortuouspaths of lower temperatures.The emerging steam chamber above the shale plates occurred by convective heat from the injection well through lower-temperature hydraulic paths between shale plates. This should have involved light to intermediate solvent components that enabled the steam chamber to expand away from the injection well. This highlights the important role of volatile solvent components in the growth of a steam chamber in SA-SAGD under heterogeneity. The produced bitumen density in this research was closer to the original bitumen than in the homogeneous SA-SAGD case because the bitumen dilution and the solvent retention increased by the tortuous flow regime resulted in efficient drainage of oil at lower temperature.
- North America > Canada (0.46)
- North America > United States (0.28)
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.90)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > New Mexico > San Juan Basin > San Juan Basin Field > Mancos Formation (0.99)
- North America > United States > Colorado > San Juan Basin > San Juan Basin Field > Mancos Formation (0.99)
Abstract Solvent injection recovery processes were introduced as a more energy-efficient and environmentally friendly alternative to Steam injection processes. However, BTX chemicals (Benzene, Toluene, and Xylene), commonly used for crude oil recovery due to their strong solvency and low asphaltene precipitation, are acutely toxic and harmful to the environment. These chemicals are easily soluble in water causing groundwater contamination. This paper evaluates the recovery efficiency of two green solvents, Limonene, and beta-pinene, on two samples of Californian heavy oil (C1 has an 874.8 cP viscosity and C2 has 178500 cP viscosity). On both C1 and C2, 5 core flood experiments were conducted, in total 10 experiments were run. CO2, limonene, and Beta-pinene were tested as solvents on both oils. Limonene and beta-pinene were both chosen due to their ready availability in the State of California. Both these solvents are plant-derived, non-toxic, and biodegradable. They also have much higher flash points than BTX solvents allowing for safer handling. They have been either injected as sole solvents or co-injected with CO2 during the experiments. Limonene and beta-pinene were injected at 2 mL/min while CO2 was injected at 2000 ml/min with a back pressure of 45-55 psi. Core packs were prepared by filling the pore space of Ottawa sand with 60% PV oil samples and 40% PV water by volume. Produced oil and water samples were collected every 20 min during the experiments. Thermogravimetric analyses (TGA/DSC) were conducted on these samples to identify oil, water, and solvent percentages. Because CO2 is insoluble in these types of high viscosity crude oils, CO2 flooding resulted in immiscibility with almost no oil production. Since both limonene and beta-pinene are aromatic solvents, by sole limonene or beta-pinene injection miscible flooding was achieved. Limonene achieved 35 and 23 vol. % oil recovery from a total of 60% oil for C1 and C2 respectively while Pinene achieved 31 and 27 vol. %. Co-injections of green solvents with CO2 are expected to yield higher recovery due to the presence of two active drive mechanisms namely miscible and immiscible. Co-injection of limonene and CO2 provided the greatest recovery with 45 vol. %, however, recovery efficiencies of pinene and CO2 had comparable recoveries with that of pinene possibly due to phase trapping. Produced samples analysis showed that oil percentages in produced samples were higher for Limonene than Pinene. Our results indicated that limonene and beta-pinene are very promising solvents for heavy oil recovery. Because these solvents are citrus-based, they are both easy to handle and non-toxic. Hence, we believe that our study can be a breakthrough for many heavy oil and bitumen reservoirs all around the world.
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Oil sand, oil shale, bitumen (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Thermal methods (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Chemical flooding methods (1.00)
- (3 more...)
New Paradigm in the Understanding of In Situ Combustion: The Nature of the Fuel and the Important Role of Vapor Phase Combustion
Gutiérrez, Dubert (AnBound Energy Inc.) | Mallory, Don (University of Calgary) | Moore, Gord (University of Calgary) | Mehta, Raj (University of Calgary) | Ursenbach, Matt (University of Calgary) | Bernal, Andrea (AnBound Energy Inc.)
Abstract Historically, the air injection literature has stated that the main fuel for the in situ combustion (ISC) process is the carbon-rich, solid-like residue resulting from distillation, oxidation, and thermal cracking of the residual oil near the combustion front, commonly referred to as "coke". At first glance, that assumption may appear sound, since many combustion tube tests reveal a "coke bank" at the point of termination of the combustion front. However, when one examines both the laboratory results from tests conducted on various oils at reservoir conditions, and historical field data from different sources, the conclusion may be different than what has been assumed. For instance, combustion tube tests performed on light oils rarely display any significant sign of coke deposition, which would make them poor candidates for air injection; nevertheless, they have been some of the most successful ISC projects. It is proposed that the main fuel consumed by the ISC process may not be the solid-like residue, but light hydrocarbon fractions that experience combustion reactions in the gas phase. This vapor fuel forms as a result of oxidative and thermal cracking of the original and oxidized oil fractions. An analysis of different oxidation experiments performed on oil samples ranging from 6.5 to 38.8°API, at reservoir pressures, indicates that this behavior is consistent across this wide density spectrum, even in the absence of coke. While coke will form as a result of the low temperature oxidation of heavy oil fractions, and while thermal cracking of those fractions on the pathway to coke may produce vapor components which may themselves burn, the coke itself is not likely the main fuel for the process, particularly for lighter oils. This paper presents a new theory regarding the nature and formation of the main fuel utilized by the ISC process. It discusses the fundamental concepts associated with the proposed theory, and it summarizes the experimental laboratory evidence and the field evidence which support the concept. This new theory does still share much common ground with the current understanding of the ISC process, but with a twist. The new insights result from the analysis of laboratory tests performed on lighter oils at reservoir pressures; data which was not available at the time that the original ISC concepts were developed. This material suggests a complete change to one of the most important paradigms related to the ISC process, which is the nature and source of the fuel. This affects the way we understand the process, but provides a unified and consistent theory, which is important for the modelling efforts and overall development of a technology that has the potential to unlock many reserves from conventional and unconventional reservoirs.
- North America > United States (1.00)
- Europe (1.00)
- North America > Canada > Alberta (0.94)
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (0.90)
- Geology > Geological Subdiscipline (0.67)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.94)
- North America > United States > Nebraska > Sloss Field (0.99)
- North America > Canada > Alberta > Athabasca Oil Sands > Western Canada Sedimentary Basin > Alberta Basin (0.99)
- North America > United States > South Dakota > Williston Basin > Buffalo Field > Red River Formation (0.94)
- North America > United States > North Dakota > Medicine Pole Hills Field (0.94)
Comprehensive Fluid Compositional Analysis Program to Support the Interpretation of Chichimene Field In-Situ Combustion Pilot
Manrique, Eduardo Jose (Ecopetrol, S.A.) | Trujillo, Marta Liliana (Ecopetrol, S.A.) | Lizcano, Juan Carlos (Consultec) | Cardenas, Diego Alejandro (Ecopetrol, S.A.) | Vanegas, Jose Walter (Ecopetrol, S.A.) | Portillo, Fredy De Jesus (Ecopetrol, S.A.) | Salazar, Helmut (Ecopetrol, S.A.) | Caicedo, Nicolas (Ecopetrol, S.A.)
Abstract The evaluation of EOR methods in Colombia has been very active during the past decade. One of the most recent and promising pilots is the In-Situ Combustion (ISC) in Chichimene Field, starting in September 2019. Based on international ISC field experiences, this pilot represents a unique case study given the depth (≈8,000 ft.) of this heavy crude oil (9°API) reservoir. The pilot project consists of one injector, seven producers, and two temperature observation wells between the injector and first-line wells. Production response shows encouraging results. Its interpretation is supported by a comprehensive fluid compositional analysis, which is the main objective of this paper. This paper describes the compositional analysis of produced fluids (gas, oil, and water) and the influence of the current flow assurance program. Geochemical simulations support the evaluation of scaling tendencies, and possible corrosion trends are based on iron and manganese concentrations following the National Association of Corrosion Engineers (NACE) standards. Crude oil analysis is based on conventional techniques (i.e., acid number, distillation curves, etc.) and biomarkers to infer possible thermal maturation changes in the produced oil. Results confirm predicted cycles of CO2 and H2S during the planning of the monitoring program. The solubility of both gases in water leads to its acidification and the formation of carbonate and sulfate scales characterized in production wells. The precipitation of solids was also influenced by the N2-based H2S scavenger decomposition downhole due to water pH increment observed with the dosage increases. The scaling tendencies did not impact the productivity due to the high reservoir permeability. The precipitation of iron species difficulted NACE standards interpretation to infer corrosion except for wells shut-in for more than two months showing a higher concentration of Fe and Mn. However, a recent casing inspection job at one of the first-line producers shows no corrosion signs. The analysis of heavy metals such as nickel and vanadium in water was also used to infer possible corrosion or thermal cracking of porphyrins present in the crude oil. Changes in the paraffinic fractions and biomarkers (i.e., methyl phenanthrene index, mono- and tri- aromatic steroids) also suggest increasing the thermal maturity of the produced oil. The robust monitoring program has provided important insights from the ISC process and flow assurance strategy supporting possible expansion plans. This study provides valuable guidelines for monitoring programs based on compositional analysis of produced fluids, including the influence of production chemistry. Lessons learned through the Chichimene ISC monitoring program can be valuable in interpreting thermal and potentially non-thermal EOR projects.
- Asia > Middle East (0.93)
- South America > Colombia > Meta Department (0.71)
- Research Report > New Finding (0.66)
- Research Report > Experimental Study (0.48)
- Geology > Mineral (1.00)
- Geology > Geological Subdiscipline > Geochemistry (1.00)
- Geology > Rock Type > Sedimentary Rock (0.93)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.35)
- South America > Venezuela > Zulia > Maracaibo Basin > Ayacucho Blocks > Lagunillas Field (0.99)
- South America > Colombia > Santander Department > Middle Magdalena Basin > Yariguí-Cantagallo Field (0.99)
- South America > Colombia > Meta Department > Llanos Basin > Quifa Block > Quifa Field (0.99)
- (6 more...)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Thermal methods (1.00)
- Reservoir Description and Dynamics > Fluid Characterization > Phase behavior and PVT measurements (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
Feasibility Study of Gas Injection in Low Permeability Reservoirs of Changqing Oilfield
Tian, Ye (Colorado School of Mines) | Uzun, Ozan (Colorado School of Mines) | Shen, Yizi (Colorado School of Mines) | Lei, Zhengdong (Research Institute of Petroleum Exploration and Development, PetroChina) | Yuan, Jiangru (Research Institute of Petroleum Exploration and Development, PetroChina) | Chen, Jiaheng (Research Institute of Petroleum Exploration and Development, PetroChina) | Kazemi, Hossein (Colorado School of Mines) | Wu, Yu-Shu (Colorado School of Mines)
Abstract Changqing Oilfield is the largest petroleum-producing field in China and one-third of its oil production is attributed to the formations with permeability lower than 1 mD. The rapid oil rate decline and low recovery factor (RF) associated with those formations require additional IOR/EOR measures besides waterflood. Based on the promising results from recent gas injection pilots in North America, we investigated the feasibility of gas injection in the low permeability formation (Chang 63) of Changqing Oilfield. An eight-component fluid characterization, which fits both the constant composition expansion (CCE) test and separator test, was used in a numerical dual-porosity compositional model. A typical well pattern, composed of six vertical injectors and one horizontal producer, is selected for the modeling study. The input parameters, including relative permeability, fracture permeability, etc., were adjusted to achieve an acceptable history match of the production data. Huff-n-Puff using several gases—lean gas (CH4), produced gas, rich gas (C2H6), and solvent (C3H8)— were investigated and the results were compared with the current waterflood. The simulation results show that the richer the injected gas, the higher the oil production. C3H8 huff-n-puff achieved the best performance, increasing the cumulative oil production by a factor of 2.28 after 5 cycles, then followed by C2H6 as 1.34, produced gas as 1.08. CH4 alone demonstrated a lower recovery factor than waterflood, because its minimum miscibility pressure (MMP) is close to the maximum allowable injection pressure, i.e., the minimum horizontal stress. In addition, the horizontal producer was completed at the reservoir top and water injectors were placed at the bottom, which was originally designed to improve the waterflood by gravity segregation. Under such well placement design, the miscible oil bank, which forms at the injection front during vaporizing drive, will be displaced towards the reservoir bottom even out of the SRV, undermining the huff-n-puff performance. Injection with rich gas will be more compatible, as the miscible bank forms at the injection tail. Injecting produced gas enriched with C3H8 will hence achieve promising EOR performance. The simulation also shows that increasing injection pressure increases the recovery factor. The leaner composition of produced gas could be compensated by a higher injection pressure. The optimal injection duration and soaking time could also be obtained after sensitivity analysis. Another critical factor is the fracture network characterized by the dual-porosity model, as simulation with the single porosity model only shows minor improvement in RF even with C3H8. Our work confirmed the technical feasibility of injecting rich gas in the low permeability Chang 63 by compositional simulation. We also determined the key parameters for the operator to consider in the next phase of the project.
- Asia > China > Shaanxi Province (1.00)
- Asia > China > Gansu Province (1.00)
- Asia > China > Shanxi Province (0.92)
- (2 more...)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.68)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.48)
- North America > United States > Texas > West Gulf Coast Tertiary Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Sabinas - Rio Grande Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Maverick Basin > Eagle Ford Shale Formation (0.99)
- (11 more...)
Laboratory Evaluation of Novel Surfactant for Foam Assisted Steam EOR Method to Improve Conformance Control for Field Applications
Mukherjee, Biplab (The Dow Chemical Company) | Patil, Pramod D. (The Dow Chemical Company) | Gao, Michael (The Dow Chemical Company) | Miao, Wenke (The Dow Chemical Company) | Potisek, Stephanie (The Dow Chemical Company) | Rozowski, Pete (The Dow Chemical Company)
Abstract Steam injection is a widespread thermal enhanced oil recovery (EOR) method to increase oil mobility. The introduction of steam heats the reservoir, ultimately lowering oil viscosity and in turn enhancing heavy oil recovery. In the steam injection process, recovery of oil is limited by steam channeling due to reservoir heterogeneities. Early breakthrough implies that there is a large consumption of steam and incomplete reservoir drainage. Injection of surfactant with steam and a non-condensable gas such as nitrogen can generate foam in situ. Foam will redirect steam, increase apparent viscosity and reduce steam channeling. Although the technology is promising, it is not always economically attractive due to the large volumes that must be injected continuously, high adsorption of surfactant on reservoir rocks, and limited thermal stability of the surfactant. The opportunity exists to design steam foam surfactant formulations with improved performance at high temperature. In this paper, a systematic approach to screen surfactants for field applications at high temperature is presented. A feasibility test was conducted with the surfactant formulation (HSF-X) at target reservoir conditions to understand the thermal stability and adsorption behavior of the surfactant. Investigation found that the thermal decomposition and adsorption of the surfactant on sandstone rock under static conditions was mimimum at 200°C. In core flood testing conducted using silica sand and natural sandstone cores, foam generated by injecting N2 and HSF-X surfactant solution was able reduce steam mobility between 40 to 100 times at 100°C and 10 to 15 times at 200°C more compared to steam mobility in the absence of the foam. Finally oil recovery experiments at 200°C using silica sand cores indicated the ability of the HSF-X surfactant to foam in the presence of oil and enhance recovery of oil (a +20% increase in the original oil in place (OOIP) was observed).
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.44)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.46)
Abstract The in-situ steam based technology is still the main exploitation method for bitumen and heavy oil resources all over the world. But most of the steam-based processes (e.g., cyclic steam stimulation, steam drive and steam assisted gravity drainage) in heavy oilfields have entered into anexhaustion stage. Considering the long-lasting steam-rock interaction, how to further enhance the heavy oil recovery in the post-steam injection era is currently challenging the EOR (enhanced oil recovery) techniques. In this paper, we present a comprehensive review of the EOR processes in the post steam injection era both in experimental and field cases. Specifically, the paper presents an overview on the recovery mechanisms and field performance of thermal EOR processes by reservoir lithology (sandstone and carbonate formations) and offshore versus onshore oilfields. Typical processes include thein-situ combustion process, the thermal/-solvent process, the thermal-NCG (non-condensable gas, e.g., N2, flue gas and air) process, and the thermal-chemical (e.g., polymer, surfactant, gel and foam) process. Some new in-situ upgrading processes are also involved in this work. Furthermore, this review also presents the current operations and future trends on some heavy oil EOR projects in Canada, Venezuela, USA and China. This review showsthat the offshore heavy oilfields will be the future exploitation focus. Moreover, currently several steam-based projects and thermal-NCG projects have been operated in Emeraude Field in Congo and Bohai Bay in China. A growing trend is also found for the in-situ combustion technique and solvent assisted process both in offshore and onshore heavy oil fields, such as the EOR projects in North America, North Sea, Bohai Bay and Xinjiang. The multicomponent thermal fluids injection process in offshore and the thermal-CO2and thermal-chemical (surfactant, foam) processes in onshore heavy oil reservoirs are some of the opportunities identified for the next decade based on preliminary evaluations and proposed or ongoing pilot projects. Furthermore, the new processes of in-situ catalytic upgrading (e.g., addition of catalyst, steam-nanoparticles), electromagnetic heating and electro-thermal dynamic stripping (ETDSP) and some improvement processes on a wellbore configuration (FCD) have also gained more and more attention. In addition, there are some newly proposed recovery techniques that are still limitedto the laboratory scale with needs for further investigations. In such a time of low oil prices, cost optimization will be the top concerns of all the oil companies in the world. This critical review will help to identify the next challenges and opportunities in the EOR potential of bitumen and heavy oil production in the post steam injection era.
- South America > Venezuela (1.00)
- Asia > Middle East (1.00)
- Asia > China (1.00)
- (7 more...)
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.34)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.92)
- South America > Venezuela > Zulia > Maracaibo Basin > Tia Juana Field (0.99)
- South America > Colombia > Putumayo Department > Putumayo Basin (0.99)
- South America > Brazil > Espírito Santo > South Atlantic Ocean > Campos Basin > Block BM-C-30 > Jubarte Field (0.99)
- (40 more...)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Oil sand, oil shale, bitumen (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Thermal methods (1.00)
Abstract Performance predictions of In-Situ Combustion (ISC) process is a challenge as it involves complicated chemical reactions, fluids movement, phase changes, and heat and mass transfer. This study investigates how the aquathermolysis reactions and their chemical products can affect the ISC performance through combination of combustion tube and Thermogravimetric Analysis and Differential Scanning Calorimetry (TGA/DSC) experiments. Combustion tube experiments were conducted with two different crude oil without water (Swi=0%) and with the presence of water (Swi=34%). Experimental conditions were kept constant (3 L/min air injection rate and 100 psig pack pressure) for all four experiments conducted with two different oil samples. To determine the chemical reactions occurred during combustion tube experiments, the initial crude oil samples and their Saturates, Aromatics, Resins, and Asphaltenes (SARA) fractions were subjected to TGA/DSC experiments under air injection at two constant heating rates with and without water addition. Because during combustion tube experiments, two heating rates were observed, 5°C/min was used to represent the slow heating region (Steam Plateau and Evaporation & Visbreaking) and 20°C/min was used to mimic the rapid heating region (Cracking Region and Combustion Zone). To better understand the complicated mutual interactions of functional groups in crude oil, TGA/DSC experiments were repeated on normal-decane (an alkane), decanal (an aldehyde), decanone (a ketone), and decanol (an alcohol) which may represent the low temperature oxidation (LTO) products. Note that these chemicals have constant carbon number (C10). The combustion tube experiments showed that Oil1 was able to burn for both conditions (with and without water), while Oil2 could only sustain combustion with water. To study the reason for this difference in burning behavior, the burning behavior of the crude oils and their individual SARA fractions with and without water addition was studied through TGA/DSC experiments. At high heating rate (20°C/min), heat generation does not vary for both crude oil. However, in low heating rates (5°C/min), Oil1 generates higher amount of energy at high temperature oxidation (HTO) zone. We have observed similarities between the decanone (a ketone) burning behaviors with aromatics fractions for Oil1 which may indicate that aromatics fraction may contain ketone functional groups as LTO products Because upon burning, ketones generate higher energy than any LTO products, Oil1 may have functional groups in its structure more like ketones which promotes its combustion more than Oil2. While presence of water does not change the burning behavior of Oil1, we observed that aromatics fraction of Oil2 in the presence of water generates components similar to decanol (an alcohols) burning behavior. Note that alcohols generate more heat than aldehydes upon burning which explains the enhancement of Oil2 burning behavior in the presence of water, however, produced less energy than ketones, hence, combustion performance of Oil2 was poorer than Oil1. Our results suggest that the chemical structure of aromatics fraction is critical for the success of ISC. Water and aromatics fraction interaction at elevated temperature favors ISC reactions.
- North America > United States > Texas (0.29)
- North America > United States > Oklahoma (0.28)
- North America > Canada > Alberta (0.28)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Energy > Oil & Gas > Downstream (1.00)
Abstract The current in situ exploitation of oil sands in Alberta employs steam-based recovery methods, which are energy-intensive. A few companies are adding solvent to steam aiming to reduce steam requirements. The mechanism of oil recovery by steam with added solvent is not clear. Over the years, on several occasions- as at the present time- the oil industry has resorted to the use of solvents with steam in thermal recovery operations. The past trials with solvent were short-lived in view of the cost of solvents as well as the lack of success. Given the controversy regarding the use of solvents with steam, this work is intended to explain whether solvent injection with steam increases oil recovery or not. In this work, a new analytical model is developed for describing the solvent-SAGD performance based on the combination of an overall solvent mass balance, heat balance and volumetric oil displacement and Darcy's oil rate using a mixture viscosity model as a function of temperature and solvent concentration ahead of front which satisfy the equilibrium in the system. The objectives of this work are to predict: vapour-steam chamber growth, oil production rate, solvent production rate, solvent loss (or solvent retention) rate, and the effect of solvent type and concentration on the solvent-SAGD process. The results show that the rate of solvent retention increases over time, while the production rates of solvent and bitumen decrease. The efficiency of this process is evaluated using Cumulative Steam-Oil Ratio (CSOR) and cumulative solvent-oil ratio, which permits a comparison of the efficiency of SAGD and solvent-SAGD processes for different solvents. On the whole, the results of this approach give a better understanding of the mechanism of oil production during the solvent-SAGD process by interconnecting vapour chamber conditions and the conditions of heated and diluted oil ahead of the interface.
- North America > United States (1.00)
- North America > Canada > Alberta (0.48)
- Research Report > New Finding (0.67)
- Research Report > Experimental Study (0.48)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Thermal methods (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Steam-solvent combination methods (1.00)
Abstract Solvent Aided-Steam Flooding (SA-SF) focuses on maximizing the oil production by reducing the economic and environmental challenges created by steam generation. However, the solvent selection is vital due to the interaction of solvents with asphaltenes. Moreover, the polar nature of asphaltenes also enables asphaltene-steam interaction which may result in emulsion formation. This study investigates solvent-asphaltene-steam interaction during SA-SF with low and high molecular weight asphaltene insoluble solvents. Two different solvents were tested; n-hexane (E1 and E4) and a commercial solvent (CS) (E2 and E5) with four flooding experiments; two miscible flooding (E1 and E2) and two SA-SF (E4 and E5) experiments. Results were compared with steam flooding (E3) experiment. The performance evaluation of different enhanced oil recovery methods was accomplished by comparing the oil recovery rates. The asphaltene content of produced oil samples was determined by standard methods. The asphaltene-steam interaction was analyzed with microscopic images, and the water content of produced oil samples was measured by Thermogravimetric Analysis (TGA). Even though similar cumulative oil productions were obtained by the end of E1 (n-hexane-flooding) and E2 (CS-flooding), the produced oil quality varied due to asphaltene and clay contents. While higher clay content was measured for E1, E2 had a lower quality, due to higher asphaltene contents. This finding is due to the heavy dearomatized hydrocarbons composition of the CS which ranges from C11 up to C16 and enables more asphaltene production. Even though, E5 yielded the highest liquid production among all experiments; the produced liquid was composed of emulsified oil. The solvent aided-steam flooding (SA-SF) experimental results, which have been conducted with n-hexane/steam (E4) and CS/steam (E5) injections, suggest that as the asphaltene content increases in produced oil samples, more hard-to-break emulsions are formed. The unusual stability of these emulsions can be attributed to the nature of the asphaltene present in the produced oil. From the results presented, it is recommended the use of lower carbon number solvents to leave the larger amounts of asphaltenes in the reservoirs. The solvents differed in their interactions with the asphaltenes present in the oil and with the steam that has a direct impact not only on the quantity of oil produced but the quality as well. Hence, the wise selection of the appropriate solvent cannot be ignored during solvent aided-steam flooding processes.
- North America > United States > Texas (0.30)
- North America > Canada > Alberta (0.30)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Thermal methods (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (1.00)
- Health, Safety, Environment & Sustainability > Environment > Climate change (1.00)
- Facilities Design, Construction and Operation > Flow Assurance > Precipitates (paraffin, asphaltenes, etc.) (1.00)