Characterization Of Gas Oil Flow In Cyclic Solvent Injection Csi For Heavy Oil Recovery

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Characterization of Gas-Oil Flow in Cyclic Solvent Injection (CSI) for Heavy Oil Recovery

Author : Sam Yeol Hong
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)

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Book Synopsis Characterization of Gas-Oil Flow in Cyclic Solvent Injection (CSI) for Heavy Oil Recovery by : Sam Yeol Hong

Download or read book Characterization of Gas-Oil Flow in Cyclic Solvent Injection (CSI) for Heavy Oil Recovery written by Sam Yeol Hong and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclic Solvent Injection (CSI) has emerged as an effective post-CHOPS recovery method. It has shown a great potential with the aid of the solvent injection under the huff-n-puff operation. The use of solvent that maintains a strong nature of gas results in the solvent chamber which under the huff-n-puff operation locates at an inner region towards the well. The CSI process is therefore governed by the gas-oil flow as the solvent chamber is dominated by the free gas-oil flow and the heavy oil zone by the dispersed gas-oil flow referred to as the foamy oil flow. The gas-oil flow in CSI eventually appears as the combined flow of free gas and foamy oil across the solvent chamber. The gas-oil flow in heavy oil systems has been widely investigated based on heavy oil solution gas drive. However, the combined flow of free gas and foamy oil in CSI considerably differs from that in heavy oil solution gas drive and therefore needs to be investigated separately. The differences mainly arise as in CSI the free gas originates from the solvent chamber whereas in heavy oil solution gas drive it evolves from solution gas. Consequently, the combined flow of free gas and foamy oil in CSI yields the characteristics that strongly depend on the pressure depletion rate and the growing solvent chamber. This study is aimed at characterizing the gas-oil flow in CSI for heavy oil recovery at different pressure depletion rates under the effect of the growing solvent chamber. To fulfill the objective, the gas-liquid relative permeability curves are inferred with the use of numerical simulations by history-matching seven lab-scale CSI tests performed at varying pressure depletion rates. The foamy oil behavior is taken into account by applying the modified-fractional flow model. This study therefore not only demonstrates the distinct properties of the gas-oil relative permeability curves in CSI process but also the applicability of the modified-fractional flow model. The sensitivity analysis is performed to examine the phenomena responsible for the distinct behavior of the gas-oil flow in CSI.

Experimental and Mathematical Studies of Cyclic Solvent Injection To Enhance Heavy Oil Recovery

Author : Zhongwei Du
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)

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Book Synopsis Experimental and Mathematical Studies of Cyclic Solvent Injection To Enhance Heavy Oil Recovery by : Zhongwei Du

Download or read book Experimental and Mathematical Studies of Cyclic Solvent Injection To Enhance Heavy Oil Recovery written by Zhongwei Du and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has been suggested that Cyclic Solvent Injection (CSI) is a highly promising technique to recover heavy oil resources at which other recovery techniques are not economically or efficiently available. Therefore, it is necessary to conduct experimental and mathematical studies on the CSI for effective heavy oil recovery purposes. Experimental and data regression studies have been conducted to investigate the effects of the wormhole on the CSI. Nine tests were completed using three sand-pack physical models with different dimensions. Experimental results suggest that the oil production can be divided into two phases: solvent chamber rising phase and solvent chamber spreading phase. The average production rate in the solvent chamber rising phase is proportional to the wormhole length, while the average production rate in the solvent chamber spreading phase does not change much with the wormhole length. In addition, a relation of the oil production rate to the drainage height is obtained by regression analysis and verified with a different experiment. It is suggested that for a rectangular model, the oil production rate in the chamber rising phase is proportional to h1.1667. Experimental study of effects of pressure decline rate on the CSI has been performed. Twelve tests with ten decline rates through linear and non-linear pressure-drawdown methods were conducted. Results of optimizing the pressure decline rate indicated that the pressure decline rate plays a primary role in the CSI by affecting solvent chamber growth, foamy oil flow performance in Phase 1, and pressure drop force in Phase 2. Different driving mechanisms in different phases lead to different optimum pressure decline rates. Comparison of two pressure-drawdown methods suggests that the main difference between the non-linear pressure-drawdown method and linear pressuredrawdown method is that the former cannot provide a continuous driving force for diluted oil as well as the latter. The effect of the intermittent driving force is much more significant in Phase 2. Therefore, production performance of tests of pressure-drawdown linearly was generally better than that of tests of pressure-drawdown non-linearly. A linear material balance equation of CSI has been proposed to obtain the recovery factor of diluted oil. It is successfully used to obtain the recovery factor of diluted oil of each cycle for a well-designed CSI test in a rectangular physical model (80×40×20 cm3). The relation of the solution-gas oil ratio and the diluted oil formation volume factor with pressure under non-equilibrium state are obtained through linear regression based the material balance equation. They are successfully verified through experimental data of a CSI test in a cylindrical model. Results indicate that the efficiency of oil dilution increases from 4.75% to 10.70% before the Cycle 10. Then it slightly varies from 10% to 16.25% till the Cycle 25. It is dramatically decreased 10.11% in the last five cycles. For first three cycles, the diluted oil recovery factor is up to 40% due to extended production time. Then it almost keeps around 32% till the Cycle 25. Three mixture solvent with the decline rate of 12.5 kPa/min ,5 kPa/min and 1 kPa/min have been conducted. Knowledge of production performance of mixture solvent CSI tests is obtained through the comparison of mixture solvent tests with different decline rate and the comparison between mixture and pure solvent tests. Pure solvent tests had larger recovery factor and average oil production per cycle than mixture solvent tests. The asphaltene precipitation and production time significantly impacted the recovery factor of diluted oil in mixture solvent tests.

Optimum Cyclic Solvent Injection (CSI) and Waterflooding/Gasflooding in the Post Cold Heavy Oil Production with Sand (Chops) Reservoirs

Download Optimum Cyclic Solvent Injection (CSI) and Waterflooding/Gasflooding in the Post Cold Heavy Oil Production with Sand (Chops) Reservoirs PDF Online Free

Author : Hongze Ma
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)

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Book Synopsis Optimum Cyclic Solvent Injection (CSI) and Waterflooding/Gasflooding in the Post Cold Heavy Oil Production with Sand (Chops) Reservoirs by : Hongze Ma

Download or read book Optimum Cyclic Solvent Injection (CSI) and Waterflooding/Gasflooding in the Post Cold Heavy Oil Production with Sand (Chops) Reservoirs written by Hongze Ma and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, the technical synergy of combining cyclic solvent injection (CSI) and waterflooding (WF) or gasflooding (GF) in a two-well configuration for the post-cold heavy oil production with sand (CHOPS) reservoirs was explored. In the experiments, the original heavy oil samples were collected from the Colony and McLaren formations in Alberta, Canada. The PVT data and viscosities of CH4/CO2/C3H8-saturated Colony/McLaren heavy oil were measured at different equilibrium pressures and Tres = 21 °C. A total of 17 sandpacked laboratory tests were conducted to examine the technical and economical merits of the combined CSI and WF/GF. Both the CSI + WF and CSI + GF recovered more heavy oil than the CSI or WF alone due to the extended foamy-oil flow. The combined CSI and WF outperformed the combined CSI and GF in terms of the heavy oil recovery factor (RF), heavy oil production rate, and cumulative gas-oil ratio (GOR) because gas channeling was hindered by the subsequently injected water. In addition, C3H8 was found to be a more dissolving and extracting solvent than CO2 due to its more favourable PVT properties and larger heavy oil viscosity reduction. The intermediate pressure drawdown rate or CO2 injection rate resulted in a higher heavy oil RF during the CSI or GF. Theoretically, an analytical material balance model (MBM) was formulated to predict the cumulative heavy oil and gas productions and the average reservoir pressure during the primary production and subsequent CSI. The non-equilibrium phase behaviour and the foamy-oil properties were taken into account in this analytical MBM. Several unknown parameters were tuned and determined by best matching the theoretically predicted data and the experimentally measured data, such as the nucleation coefficient of dissolved CH4 in the heavy oil and the decay coefficient of dispersed CH4 bubbles from the heavy oil. The predicted cumulative heavy oil productions and average reservoir pressures during the primary production and subsequent CSI agreed well with the measured data. However, there were large discrepancies between the predicted and measured cumulative gas productions in the CSI because of its gas channeling, which is a major technical issue encountered in the CSI. In addition, it was found that dissolved CH4 in the heavy oil became the dispersed CH4 bubbles more quickly when the nucleation coefficient was larger at a higher pressure drawdown rate or in a less viscous heavy oil. The foamy heavy oil with the dispersed CH4 bubbles was more stable when the decay coefficient was smaller at an increased pressure drawdown rate or in a more viscous heavy oil. Numerical simulations were undertaken to optimize the CSI, CSI + WF, and CSI + GF after the primary production in a representative and synthetic field-scale heavy oil reservoir by choosing the net present value (NPV) as an objective function. The steepest ascent (SA) method and the particle swarm optimization (PSO) were utilized to find the optimum well controls and maximize the NPV. Both the SA method and PSO efficiently determined nearly optimum NPVs for the CSI, CSI + WF, and CSI + GF in the heavy oil reservoirs with/without the wormholes. It was found in this study that the NPV of the CSI + GF was the highest in the post-CHOPS reservoir. The oil producer should be operated at the minimum allowable bottom hole pressure (BHP) during the entire reservoir life. The gas injector should be used to inject at the maximum allowable injection rate during the early cycles but shut in during the late cycles to control the gas channeling.

Cyclic Hot Solvent Injection Method to Enhance Heavy Oil Recovery Based on Experimental Study

Author : Kewei Zhang
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)

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Book Synopsis Cyclic Hot Solvent Injection Method to Enhance Heavy Oil Recovery Based on Experimental Study by : Kewei Zhang

Download or read book Cyclic Hot Solvent Injection Method to Enhance Heavy Oil Recovery Based on Experimental Study written by Kewei Zhang and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the solvent-based heavy oil recovery methods, the cyclic solvent injection (CSI) method has been acknowledged as an effective method with high oil production rate. Oil recovery in pure solvent CSI study is as high as over 70%. However, injection pressure in the pure solvent CSI is limited by the low dew point pressure of hydrocarbon at laboratory ambient temperature condition. In the mixture gas CSI method, although the solvent dew point pressure can be raised at the ambient temperature condition, recovery factor of this method is much lower than that of pure solvent CSI method. Therefore, it is necessary to explore an alternative CSI method which takes advantage of both pure gas-based and mixture gas-based CSI methods. As raising the pure solvent injection temperature can increase the solvent dew point pressure, the idea of hot solvent CSI is experimentally tested in this study. This new type of CSI method is named the cyclic hot solvent injection method (CHSI). In the CHSI laboratory study, hot solvent can reach high initial reservoir pressure. The experimental system consists of a sand-pack model unit, injection unit, production unit and data acquisition unit. Three major topics have been studied concerning CHSI: the comparison between CHSI and the replaceable method of CHSI (the mixture gas CSI method), the comparison between CHSI and the "N-Solv" (hot vapor solvent extraction) method, and temperature sensitivity analysis in CHSI. Experimental results show that, for the first topic, oil recovery of CHSI method is much higher than it is in mixture gas CSI method; for the second topic, oil production performance of CHSI is compared with that II in N-Solv; for the third topic, three solvent injection temperature levels are compared with each other in order to study solvent temperature effect on the oil production performance. Experimental results show that the CHSI method is an effective heavy oil extraction method, because this method is superior to mixture gas CSI method and N-Solv method regarding oil recovery. Oil recovery of CHSI is hardly influenced by solvent injection temperature. However, solvent injection temperature positively affects oil production rate during early CSI production period.

Experimental Study of Foamy Oil Characteristics and Post-CHOPS CSI Processes Based on CO2-C3H8 Mixture Solvent

Author : Chen Shen
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)

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Book Synopsis Experimental Study of Foamy Oil Characteristics and Post-CHOPS CSI Processes Based on CO2-C3H8 Mixture Solvent by : Chen Shen

Download or read book Experimental Study of Foamy Oil Characteristics and Post-CHOPS CSI Processes Based on CO2-C3H8 Mixture Solvent written by Chen Shen and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the demand of crude oil increases sharply nowadays, heavy oil, an unconventional liquid hydrocarbon representing more than 70% of the world's total oil, needs to be further produced in the coming decades. Although some laboratory experiments have been conducted to find out the mechanism of foamy oil during pressure depletion processes. There are still some difficulties in understanding the characteristics of foamy oil flow in Cold Heavy Oil Production (CHOP). Large amounts of heavy oil samples used in previous studies were mixed with methane, carbon dioxide and butane. Only several studies were conducted under heavy oil-mixture solvent systems. Therefore, it is of great significance to carry out some experiments to perceive the foamy oil flow characteristics with its influencing factors in heavy oil-mixture solvent (CO2-C3H8) systems so as to get better recovery factors in primary production. In this study, four pressure depletion tests were conducted in 1D sand pack model to find out factors affecting the duration of foamy oil flow and recovery factors were obtained as the result. Firstly, all the conditions were the same except for the decline rate (-1, -2, -6, -12 kPa/min). Secondly, the optimized depletion rate was applied into the next stage experiments which was used to understand the length effect on foamy oil flow characteristics. Once all the depletion tests had been completed, another four post-CHOPS CSI tests were conducted to find out whether gravity can take effect on the oil recovery factors. Results show that in CO2-C3H8 mixture solvent-heavy oil system, oil recovery factor increases as the depletion rate becomes larger. Furthermore, compared with pure solvent heavy oil system, mixture solvent shows better during depletion tests. Besides, results show that there is a positive correlation between oil recovery factor and gravity. Last but not least, results from the pressure depletion tests indicate that pressure gradient will become smaller at the end as the model length increases. In the oil field, pressure gradient remains a low level when it is far away from the well bore and that is one reason for low cumulative oil production.

Experimental Study on Foamy Oil Flow by Using Different Heavy Oil-Solvent Systems

Author : Xiang Zhou
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)

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Book Synopsis Experimental Study on Foamy Oil Flow by Using Different Heavy Oil-Solvent Systems by : Xiang Zhou

Download or read book Experimental Study on Foamy Oil Flow by Using Different Heavy Oil-Solvent Systems written by Xiang Zhou and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Foamy oil flow that occurs in heavy oil reservoirs under solution gas drive in the primary production process, shows an anomalous production performance compared with that in conventional solution gas drive reservoirs [Maini, 2001]. Although several laboratory experimental studies have been carried out to research the mechanisms of foamy oil flow in physical models, and the production performance effects of pressure depletion rates on foamy oil flow have been studied, it remains difficult to understand the process clearly. Meanwhile, many oil samples used in previous studies were on heavy oil-methane systems or heavy oil-CO2 systems, rarely on heavy oil-propane systems. Therefore, it is of crucial importance to understand the solution gas drive mechanisms in heavy oil reservoirs with different hydrocarbon solvent gases (methane, propane, and mixture) under different constant pressure depletion rates, so as to guide a better cold heavy oil production. In this study, pressure depletion tests on foamy oil flow were conducted in two kinds of apparatus, namely the Pressure-Volume-Temperature (PVT) system and the sandpack system, to investigate the effects of the pressure depletion rate on different heavy oil-solvent systems in bulk phase and porous media, respectively. Pure methane, pure propane, and a mixture of methane and propane were recombined into a Manatokan dead heavy oil sample to generate live oil samples, respectively. For the heavy oil-pure solvent system, both the PVT tests using the Constant Component Expansion (CCE) approach under constant volume depletion rates and the sandpack tests under constant pressure depletion rates were conducted to examine the effects of different pressure operation schemes on improving foamy oil recovery efficiency. For the heavy oil-mixture system, only sandpack tests were developed under constant pressure depletion rates to study the mixture effects on foamy oil flow. For each heavy oil-solvent system, four different volume or pressure depletion rates were undertaken; in total, eight PVT tests and twelve sandpack tests were carried out in this study. The experimental results showed that for the PVT tests, the plots of pressure versus time elapses and volume changes versus pressure declines of the heavy oil-methane system were much smooth than those of the heavy oil-propane system, which means the volume increase rates of the oil mixture and bulk phase are synchronous in the heavy oil-methane system. However, in the heavy oil-propane system, the volume increase rate of the oil mixture was lower than that of the volume increase rate in the bulk phase. Due to the high solubility of propane in heavy oil, the nucleated bubbles were trapped in the heavy oil and it was difficult for them to evolve out; the propane was recombined into the live oil simultaneously with undergoing the dynamic process undergoing, resulting in appearance of fluctuations in the plots. For the sandpack tests, the trend of oil production recovery factor is different from former researches which indicated that the oil recovery factor has a proportional relationship with pressure depletion rates. In this study, the oil recovery factor plot has a non-linear relation with pressure depletion rates, and there are summits in the recovery plots for the three heavy oil-solvent systems. Finally, for the three heavy oil-solvent systems a brief chart, from which pressure depletion rates can be optimized for the foamy oil flow and Cyclic Solvent Injection (CSI) processes, was developed.

Modeling of Enhanced Heavy Oil Recovery Processes

Author : Zinqian Lu
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (137 download)

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Book Synopsis Modeling of Enhanced Heavy Oil Recovery Processes by : Zinqian Lu

Download or read book Modeling of Enhanced Heavy Oil Recovery Processes written by Zinqian Lu and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many heavy oil reservoirs are now developed by enhanced heavy oil recovery methods, such as solvent-based recovery techniques. The solvent-based recovery techniques have advantages in energy effectiveness, cost efficiency, and environmental benefits compared with other methods. In the application of solvent-based recovery techniques, many types of solvent are available, including methane (C1), propane (C3), carbon dioxide (CO2), and solvent mixture. Foamy oil flow is considered an essential mechanism and has been extensively studied. For each heavy oil-solution gas system, the flow behavior is unique, and a systematic study is necessary to understand the foamy oil mechanism better. Previously proposed simulation models did not history match the production data and pressure distribution simultaneously. This deficiency would increase the uncertainty of the simulation result and influence the subsequent evaluation or prediction of the enhanced heavy oil recovery process since the pressure incremental is not captured. This work provides an innovative methodology to characterize foamy oil flow and gas-oil two-phase flow in heavy oil-different solvent systems. For each heavy oil-solvent system, a reliable non-equilibrium simulation model is developed and validated with sand-pack model pressure depletion tests by capture the production data and pressure distribution. This work consists of a systematic simulation study using the same heavy oil sample with different types of solvent. Since the mobility ratio between the solvent and heavy oil in applying solvent-based recovery techniques is very high, the frontal instabilities are also widely observed at the two-phase interface. The instabilities grow and form the viscous fingering phenomenon. Due to the existence of viscous fingering, the breakthrough time is shortened significantly, which will impact the oil recovery and swept efficiency. Since the description and prediction of the two-phase frontal instabilities in the porous media is always a challenge, most current work is based on theoretical models and rarely validated with lab tests. In addition, previous modeling works of frontal instabilities were mainly conducted in the Hele-Shaw model or micromodel, not in the sand-pack model. Hence, previous conducted experimental works were not analyzed with the simulation study in the porous media. In this work, a simulation model is developed by adopting the Volume of Fluid (VOF) method coupled with the Level-Set (LS) method to capture and track the immiscible two-phase interface between oil and water. Then the simulation results of viscosity fingering are validated with lab tests in the porous media in terms of qualitative (frontal instability morphological characteristics) and quantitative (breakthrough time) aspects. The characterization of the frontal instabilities (viscosity fingering) is investigated under different displacing rates and viscosities. It is very challenging to describe and predict both the foamy oil flow and frontal instabilities at the same time during the enhanced heavy oil recovery process. Therefore, this research conducted simulation works and validated with lab tests for each process (foamy oil flow and viscosity fingering) separately. The conducted researches provide numerical simulation methods and reliable simulation models that could be applied to further studies on the history match and prediction of field application. Moreover, the conducted researches allow future research to consider both phenomena (foamy oil flow and viscosity fingering) that happened in the enhanced heavy oil processes by integrating the proposed simulation models in this work.

Experimental and Numerical Investigation of Cyclic Solvent Injection (CSI) Performance in Heavy Oil Systems In The Presence of Wormhole Networks

Download Experimental and Numerical Investigation of Cyclic Solvent Injection (CSI) Performance in Heavy Oil Systems In The Presence of Wormhole Networks PDF Online Free

Author : Nathan Abraham David
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)

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Book Synopsis Experimental and Numerical Investigation of Cyclic Solvent Injection (CSI) Performance in Heavy Oil Systems In The Presence of Wormhole Networks by : Nathan Abraham David

Download or read book Experimental and Numerical Investigation of Cyclic Solvent Injection (CSI) Performance in Heavy Oil Systems In The Presence of Wormhole Networks written by Nathan Abraham David and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Optimal Solvent and Well Geometry for Production of Heavy Oil by Cyclic Solvent Injection

Author : Jin Xiu Qi
Publisher :
ISBN 13 :
Total Pages : 168 pages
Book Rating : 4.:/5 (762 download)

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Book Synopsis Optimal Solvent and Well Geometry for Production of Heavy Oil by Cyclic Solvent Injection by : Jin Xiu Qi

Download or read book Optimal Solvent and Well Geometry for Production of Heavy Oil by Cyclic Solvent Injection written by Jin Xiu Qi and published by . This book was released on 2005 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Mechanics of Oil and Gas Flow in Porous Media

Author : Dang Li
Publisher : Springer Nature
ISBN 13 : 9811573131
Total Pages : 343 pages
Book Rating : 4.8/5 (115 download)

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Book Synopsis Mechanics of Oil and Gas Flow in Porous Media by : Dang Li

Download or read book Mechanics of Oil and Gas Flow in Porous Media written by Dang Li and published by Springer Nature. This book was released on 2020-08-17 with total page 343 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses various aspects of percolation mechanics. It starts with the driving forces and driving modes and then examines in detail the steady state percolation of single-phase incompressible fluids, percolation law of natural gas and percolation of non-Newtonian fluids. Progressing from simple to complex concepts, it also analyzes Darcy’s law, providing a basis for the study of reservoir engineering, oil recovery engineering and reservoir numerical simulation. It serves as a textbook for undergraduate students majoring in petroleum engineering, petroleum geology and groundwater engineering, and offers a valuable reference guide for graduate students, researchers and technical engineers engaged in oil and gas exploration and development.

Role of C3H8 and CH4 in Enhancing the Foamy Oil Phenomena and Performance of CO2-Based Cyclic Solvent Injection in Heavy Oil Systems

Author : Arash Ahadi
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)

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Book Synopsis Role of C3H8 and CH4 in Enhancing the Foamy Oil Phenomena and Performance of CO2-Based Cyclic Solvent Injection in Heavy Oil Systems by : Arash Ahadi

Download or read book Role of C3H8 and CH4 in Enhancing the Foamy Oil Phenomena and Performance of CO2-Based Cyclic Solvent Injection in Heavy Oil Systems written by Arash Ahadi and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: As light oil resources are continuously depleted, heavy oil exploitation is nowadays being put on agenda to meet the ever-increasing energy demand. Cyclic Solvent Injection (CSI) technique holds great promise as a viable approach to produce heavy oil from thin reservoirs where thermal and gravity-dominated recovery methods fail to sufficiency (and economically) recover oil. CSI, with CO2 being used as the solvent, has become a subject of several investigations and considerable speculation in light oil systems. Nevertheless, not too many studies ventured into realm of application of CO2 in heavy oil systems. In addition, importance of C3H8 and CH4 in the injected CO2 stream has been addressed in the literature; however, the details of the optimum mixing ratio of these two hydrocarbon solvents are the main knowledge gap that needs to be addressed. In this study, series of cyclic injection tests of pure CO2, CH4-CO2, C3H8-CO2, C3H8-CH4, and C3H8-CH4-CO2 were conducted at various operating pressures and mixture compositions to different (in terms of viscosity) heavy oil samples. Sand pack models with absolute permeability of kabs = 6-10 D and porosity of ø = 27-32% were used as representatives of a typical heavy oil reservoir. It was attempted to measure the CO2/solvent apparent solubility, solvent-produced oil asphaltene content, duration of produced-oil foamy shape stability, and oil recovery in each cycle to probe into the trend of responsible mechanisms during each cycle of CSI. Results showed that there is an optimum pressure in cyclic CO2 injection process in heavy oil systems; the pressure beyond which the ultimate oil recovery factor (RF) did not notably improve (near 4.82 MPa in this study). Higher concentration of C3H8 in the CO2 stream improved the oil recovery during cyclic injection. However, ultimate RF was not noticeably increased when C3H8 concentration in the mixture exceeded a certain value (near 50 mole% in this study). Although C3H8 showed effective role on the performance of CSI, it was found that the recovery factor reduces with increased CH4 concentration in the CO2 stream. The highest recovery factor of 73.8% was obtained by injecting mixture of 50% C3H8 - 50% CO2 into 1850 mPa.s viscous oil sample under the operating pressure of Pinj = 1.72 MPa. The results of CSI tests on the heavy oil with viscosity of 6430 mPa.s were lower by almost 20% since the solvent solubility was noticeably lower. Performing C3H8-CH4 tests to 6430 mPa.s viscous oil revealed that there is an optimum fraction of C3H8 in CH4 stream (near 50 mole% in this study). Moreover, partially replacement of C3H8 with CO2 (50% C3H8 - 50% CH4 with 30% C3H8 - 40% CH4 - 30% CO2) was effective (and profitable) as the achieved ultimate RF were more or less the same. No oil production was observed after conducting the first cycle injection of optimum quantified solvents on oil with the viscosity of 22 000 mPa.s. Small values of Solvent Utilization Factor (SUF), relatively high values of Solvent Oil Ratio (SOR), and low quality of the produced oil in the last cycles suggest that higher cycle numbers of CSI in heavy oil reservoirs is depending on the economic limits and might be conducted cautiously.

Nonequilibrium Phase Behaviour and Mass Transfer of Alkane Solvents(s)-CO2-Heavy Oil Systems Under Reservoir Conditions

Author : Yu Shi
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)

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Book Synopsis Nonequilibrium Phase Behaviour and Mass Transfer of Alkane Solvents(s)-CO2-Heavy Oil Systems Under Reservoir Conditions by : Yu Shi

Download or read book Nonequilibrium Phase Behaviour and Mass Transfer of Alkane Solvents(s)-CO2-Heavy Oil Systems Under Reservoir Conditions written by Yu Shi and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During primary heavy oil recovery, a unique phenomenon has been found to be closely associated with an unexpected high recovery factor, a remarkably low gas-oil ratio, and a higher-than-expected well production rate due mainly to the foamy nature of viscous oil containing gas bubbles. Even for secondary and tertiary recovery techniques, it is possible to artificially induce foamy oil flow in heavy oil reservoirs by dissolution with injected gases (e.g., CO2 and alkane solvents), which is characterized by time-dependent (i.e., nonequilibrium) phase behaviour. The entrained gas bubbles in the heavy oil are considered as the main mechanism accounting for such distinct phase behaviour. Therefore, it is of fundamental and practical importance to quantify the nonequilibrium phase behaviour and mass transfer of alkane solvent(s)-CO2-heavy oil systems under reservoir conditions. A novel and pragmatic technique has been firstly developed and validated to accurately quantify the preferential diffusion of each component in alkane solvent(s)- assisted recovery processes with consideration of natural convection induced by the heated and diluted heavy oil. The Peng-Robinson equation of state, heat transfer equation, and diffusion-convection equation are coupled to describe both mass and heat transfer for the aforementioned systems. The individual diffusion coefficient between each component of a gas mixture and liquid phase is respectively determined once either the deviation between the experimentally measured and theoretically calculated mole fraction of CO2/solvents or the deviation between the experimentally measured dynamic swelling factors and the theoretically calculated ones has been minimized. ii A robust and pragmatic technique has also been developed to quantify nonequilibrium phase behaviour of alkane solvent(s)-CO2-heavy oil systems at a constant volume expansion rate and a constant pressure decline rate, respectively. Experimentally, constant-composition expansion (CCE) tests have been conducted for alkane solvent(s)-CO2-heavy oil systems with a PVT setup, during which not only pressure and volume are simultaneously monitored and measured, but also gas samples were respectively collected at the beginning and the end of experiments to perform compositional analysis. Theoretically, mathematical formulations have been developed to quantify the amount of the evolved gas as a function of time, while mathematical models for compressibility and density of the oleic phase mixed with the entrained gas (i.e., foamy oil) are respectively formulated. In addition to a mechanistic model for quantifying a single gas bubble growth, a novel and pragmatic technique has been proposed and validated to quantify dynamic volume of foamy oil for the aforementioned systems under nonequilibrium conditions by taking preferential mass transfer of each component in a gas mixture into account. The individual diffusion coefficient of each gas component with consideration of natural convection is found to be larger than that obtained with conventional methods. An increase in either volume expansion rate or pressure decline rate would increase the critical supersaturation pressure, whereas a high temperature leads to a low critical supersaturation pressure. When pressure is below the pseudo-bubblepoint pressure, density and compressibility of foamy oil are found to sharply decrease and increase at the pseudo-bubblepoint pressure, respectively. Also, pseudo-bubblepoint pressure and rate of gas exsolution is found to be two mechanisms dominating the volume-growth rate of the evolved gas, which is directly proportional to supersaturation pressure, pressure decline rate, and concentration of each gas component under nonequilibrium conditions.

Heavy Crude Oil Recovery

Author : E. Okandan
Publisher : Springer Science & Business Media
ISBN 13 : 9400961405
Total Pages : 431 pages
Book Rating : 4.4/5 (9 download)

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Book Synopsis Heavy Crude Oil Recovery by : E. Okandan

Download or read book Heavy Crude Oil Recovery written by E. Okandan and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: Within the last 10 years the world has come to a point where the easily explorable oil deposits have now been found, and it is anticipated that such deposits will be depleted by the beginning of the Twenty-first Century. However, the increasing demand of man kind for energy has caused technologists to look into ways of find ing new sources or to reevaluat:e unconventional sources which, in the past, have not been economical. In this respect, heavy crude and tar sand oils are becoming important in fulfilling the world's energy requirements. What are heavy crude and tar sand oils? There is still some confusion as to their definitions, inasmuch as they vary among organizations and countries. In an effort to set agreed meanings, UNITAR, in a meeting in February 1982 in Venezuela, proposed the following definitions (see also Table 1): 1. Heavy crude oil and tar sand oil are petroleum or petroleum like liquids or semi-solids naturally occurring in porous media. The porous media are sands, sandstone, and carbonate rocks. 2. These oils will be characterized by viscosity and density. Viscosity will be used to define heavy crude oil and tar sand oil, and density (oAPI) will be used when viscosity measurements are not available. 3. Heavy crude oil has a gas-free viscosity of 100-10000 mPa.s (cp) 3 o at reservoir temperatures, or a density of 943 kg/m (20 API) 3 o o to 1000 kg/m (10 API) at 15.6 C and at atmospheric oressure.

Experimental Testing of Solvent Assisted Cyclic Steam Injection in Heavy Oil Reservoirs

Author : Nirbendra KC
Publisher :
ISBN 13 :
Total Pages : 242 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Experimental Testing of Solvent Assisted Cyclic Steam Injection in Heavy Oil Reservoirs by : Nirbendra KC

Download or read book Experimental Testing of Solvent Assisted Cyclic Steam Injection in Heavy Oil Reservoirs written by Nirbendra KC and published by . This book was released on 2017 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Miscible Displacement

Author : Fred I. Stalkup
Publisher :
ISBN 13 :
Total Pages : 224 pages
Book Rating : 4.F/5 ( download)

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Book Synopsis Miscible Displacement by : Fred I. Stalkup

Download or read book Miscible Displacement written by Fred I. Stalkup and published by . This book was released on 1983 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Numerical Study of Oil Displacements by Three Hydrocarbon Phases

Author : Zhongguo Xu
Publisher :
ISBN 13 :
Total Pages : 96 pages
Book Rating : 4.:/5 (956 download)

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Book Synopsis Numerical Study of Oil Displacements by Three Hydrocarbon Phases by : Zhongguo Xu

Download or read book Numerical Study of Oil Displacements by Three Hydrocarbon Phases written by Zhongguo Xu and published by . This book was released on 2016 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solvent injection is a widely used method to enhance oil recovery (EOR). Mixtures of reservoir oil and solvents can exhibit complex multiphase behavior at temperatures typically below 120°F, in which a third solvent-rich liquid (L2) can coexist with the oleic (L1) and gaseous (V) phases. Reliable design of such gas injection requires a detailed understanding of oil recovery mechanisms in three-hydrocarbon-phase flow. In prior research, three-hydrocarbon-phase displacement exhibited a higher level of miscibility with leaner gas (i.e. at a higher level of methane dilution), which resulted in a nonmonotonic trend of oil recovery with respect to gas enrichment. However, no theoretical explanation was given as to why oil displacement was more efficient at a lower level of gas enrichment. Details of oil recovery in three-hydrocarbon-phase flow are not fully understood. This research is concerned with details of oil recovery in three-hydrocarbon-phase flow by use of compositional simulation. First, the mass transfer on multiphase transitions between two and three phases is studied for oil displacement by three hydrocarbon phases. Simple conditions are derived for the multiphase transitions that yield high local displacement efficiency by three hydrocarbon phases. A nonmonotonic trend of oil recovery can occur when local oil displacement by three hydrocarbon phases becomes more efficient, but slower, with decreasing pressure or decreasing gas enrichment. Secondly, an improved method for robust phase identification is developed and implemented in a 1D convective flow simulator with no volume change on mixing. This part of research is important for further confirmation of the oil-displacement mechanisms identified for three-hydrocarbon-phase flow at different flow conditions (e.g., different relative permeabilities). The new method uses tie triangles and their normal unit vectors tabulated as part of the simulation input information. The method can properly recognize five different two-phase regions surrounding the three-phase region; the two two-phase regions that are super-CEP, and the three different two-phase regions that originate with the corresponding edges of the three-phase region in the sub-CEP region. Finally, the displacement mechanisms of three-hydrocarbon-phase flow derived in a preceding part are confirmed by use of different relative permeability models for various oil displacements. Simulation results confirm that the effect of relative permeability on displacement efficiency diminishes as the miscibility level increases. The distance parameters derived before can properly represent the interaction of phase behavior and mobilities since they are derived from mass conservation, not only from thermodynamic conditions.

Simultaneous Phase-stability/-split Computation for Multiphase Oil-displacement Simulation

Author : Di Zhu
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Simultaneous Phase-stability/-split Computation for Multiphase Oil-displacement Simulation by : Di Zhu

Download or read book Simultaneous Phase-stability/-split Computation for Multiphase Oil-displacement Simulation written by Di Zhu and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solvent injection is a widely used method for enhanced oil recovery. Phase behavior of reservoir-oil/injection-gas mixtures should be effectively used for successful implementation of solvent injection. Complex phase behavior involving three hydrocarbon phases has been observed for many solvent injection processes at temperatures typically below 120°F. Well-known examples are CO2 injection for West Texas oils and enriched gas injection for Alaskan viscous oils, for which the multiphase behavior consisted of the oleic, solvent-rich liquid, and gaseous phases. Such multiphase behavior makes it challenging to study details of solvent injection. Firstly, it is computationally difficult to robustly solve for multiphase behavior using an equation of state. Secondly, how the interplay between multiphase flow and multiphase behavior affects oil displacement is much more involved than the traditional gas injection problem with only two hydrocarbon phases. This research is concerned with two main technical challenges in multiphase behavior modeling for solvent injection: robust multiphase flash calculation, and quantification of the miscibility development through three-hydrocarbon-phase flow. In the initial part of this dissertation, a novel algorithm is presented for multiphase isobaric isothermal flash. The formulation is derived from global minimization of the Gibbs free energy using the tangent plane defined at an equilibrium phase composition at a specified temperature and pressure. The new algorithm solves for two groups of stationary points of the tangent-plane-distance (TPD) function: tangent and non-tangent stationary points of the TPD function. Equilibrium phases, at which the Gibbs free energy is tangent to the TPD function, are found as a subset of the solution. Unlike the traditional flash algorithms, the new algorithm does not require finding false solutions for robust multiphase flash. The advantage of the new algorithm in terms of robustness is shown to be more pronounced for more complex phase behavior, for which multiple local minima of the TPD function are present. It can be robustly initialized even when no K value correlation is available for the fluid of interest; e.g., multiphase behavior involving a solvent-rich liquid phase. The final part of this dissertation presents a straightforward application of a mass conservation equation to explain and quantify the local oil displacement efficiency in three-hydrocarbon-phase flow. Mass conservation dictates how components must partition into phases upon a multiphase transition (e.g., between two and three phases) in multiphase convective flow. Detailed analysis of multiphase compositional flow equations leads to the distance parameter that quantifies the level of the miscibility developed between a displaced phase and a displacing phase in the presence of other immiscible phases. This distance parameter becomes zero when multicontact miscibility is developed, for example, between the oleic and solvent-rich liquid phases in the presence of the gaseous phase in low-temperature CO2 flooding. However, the application of the distance parameter is complicated when a composition path is calculated by using the equation-of-state compositional formulation that takes into account volume change on mixing. In such an application, the mapping of the distance parameter from volume space to composition space was performed, which made the calculated distance parameter less accurate near a displacement front where the solvent concentration rapidly changes. In this research, the distance parameter is applied directly in volume space for a given composition path. This is a more direct and accurate way to validate the utility of the distance parameter to quantify the local displacement efficiency in three-phase flow. A composition path in three-phase oil displacement is obtained by numerically solving 1-D convective compositional flow equations with no volume change on mixing in this research. The new flash algorithm mentioned above is implemented in this in-house slim-tube simulator. In case studies based on experimental data, the distance parameter is shown to successfully quantify the local oil displacement efficiency in three-phase flow. It properly captures the effects of numerical dispersion and relative permeability on the development of multicontact miscibility. This is because the distance parameter is derived by a simple rearrangement of the weak form of a compositional flow equation.