Enhanced Oil Recovery Research Papers (original) (raw)

Asphaltene is a component of crude oil that has been reported to cause severe problems during production and transportation of the oil from the reservoir. It is a solid component of the oil that has different structures and molecular makeup which makes it one of the most complex components of the oil. This research provides a detailed review of asphaltene properties, characteristics, and previous studies to construct a guideline to asphaltene and its impact on oil recovery. The research begins with an explanation of the main components of crude oil and their relation to asphaltene. The method by which asphaltene is quantified in the crude oil is then explained. Due to its different structures, asphaltene has been modeled using different models all of which are then discussed. All chemical analysis methods that have been used to characterize and study asphaltene are then mentioned and the most commonly used method is shown. Asphaltene will pass through several phases in the reservoir beginning from its stability phase up to its deposition in the pores, wellbore, and facilities. All these phases are explained, and the reason they may occur is mentioned. Following this, the methods by which asphaltene can damage oil recovery are presented. Asphaltene rheology and flow mechanism in the reservoir are then explained in detail including asphaltene onset pressure determination and significance and the use of micro-and nanofluidics to model asphaltene. Finally, the mathematical models, previous laboratory, and oilfield studies conducted to evaluate asphaltene are discussed. This research will help increase the understanding of asphaltene and provide a guideline to properly study and model asphaltene in future studies.

- by and +2
- •
- Enhanced Oil Recovery, Unconventional Reservoir, Petroleum Engineering

Reservoir simulations of CO* injection into a water flooded oil reservoir show that significant amounts of oil may be recovered, and a high storage capacity of CO, is obtained also through displacement of water. Simulated storage capacities for CO, injection into an aquifer vary in the range 13-68% pore volume, depending on the prevailing displacement mechanisms.

- by Erik Lindeberg
- •
- Conservation, Migration, Enhanced Oil Recovery, Reservoir Simulation

Investigation has been made to characterize the surfactant solution in terms of its ability to reduce the surface tension and the interaction between surfactant and polymer in its aqueous solution. A series of flooding experiments have been carried out to find the additional recovery using surfactant and surfactant polymer slug. Approximately 0.5 pore volume (PV) surfactant (Sodium dodecylsulfate) slug was injected in surfactant flooding, while 0.3 PV surfactant slug and 0.2 PV polymer (partially hydrolyzed polyacrylamide) slug were injected for surfactantpolymer flooding. In each case chase water was used to maintain the pressure gradient. The additional recovery in surfactant and polymer augmented surfactant flooding were found around 20% and 23% respectively.

- by Keka Ojha
- •
- Chemical Engineering, Chemistry, Petroleum, Enhanced Oil Recovery

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- by Syed Esam Mahmood
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- Segregation, Reservoir Engineering, Enhanced Oil Recovery, Reservoir Simulation

Transport of emulsions in porous media is relevant to several subsurface applications. Many enhanced oil recovery (EOR) processes lead to emulsion formation and as a result conformance originating in the flow of a dispersed phase may arise. In some EOR processes, emulsion is injected directly as a mobility control agent. Modeling the flow of emulsion in porous media is extremely challenging due to the complex nature of the associated flows and numerous interfaces. The descriptions based on effective viscosity are not valid when the drop size is of the same order of magnitude as the pore-throat characteristic length scale. An accurate model of emulsion flow through porous media should describe this local change in mobility. The available filtration models do not take into account the variation of the straining and capturing rates with the local capillary number. In this work, we present experiments of emulsion flow through sandstone cores of different permeability and a first step on a capillary network model that uses experimentally determined pore-level constitutive relationships between flow rate and pressure drop in constricted capillaries to obtain representative macroscopic flow behavior emerging from microscopic emulsion flow at the pore level. A parametric analysis is conducted to study the effect of the permeability and dispersed phase droplet size on the flow response to emulsion flooding in porous media. The network model predictions qualitatively describe the oil-water emulsion flow behavior observed in the experiments.

- by Mao Romero
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- Engineering, Multiphase Flow, Enhanced Oil Recovery, Mathematical Sciences

The vision of the Gulf Coast Carbon Center is to seek to impact global levels of GHG in the atmosphere by doing science and engineering studies that will support reduction of CO2 emissions and enable the development of an economically viable, multifaceted, CO2 sequestration industry in the Gulf Coast. This industrial-academic consortium is investigating issues related to assessing the pathways that would make capture and pipeline transportation economically feasible and environmentally effective within a specific regional context. Key issues considered are capture in the context of the current market, pipeline infrastructure, the role of enhanced oil recovery, and permanence in a basin with many wells. .

The Vapor Extraction (VAPEX) process, a newly developed Enhanced Oil Recovery (EOR) process to recover heavy oil and bitumen, has been studied theoretically and experimentally and is found a promising EOR method for certain heavy oil... more

- by behzad rostami
- •
- Petroleum, Enhanced Oil Recovery, Gravity, Permeability

A new generation improved oil recovery methods comes from combining techniques to make the overall process of oil recovery more efficient. One of the most promising methods is combined Low Salinity Surfactant (LSS) flooding. Low salinity brine injection has proven by numerous laboratory core flood experiments to give a moderate increase in oil recovery. Current research shows that this method may be further enhanced by introduction of surfactants optimized for lowsal environment by reducing the interfacial tension. Researchers have suggested different mechanisms in the literature such as pH variation, fines migration, multi-component ionic exchange, interfacial tension reduction and wettability alteration for improved oil recovery during lowsal injection. In this study, surfactant solubility in lowsal brine was examined by bottle test experiments. A series of core displacement experiments was conducted on nine crude oil aged Berea core plugs that were designed to determine the impac...

A halothermotolerant Gram-positive sporeforming bacterium was isolated from petroleum reservoirs in Iran and identified as Bacillus licheniformis sp. strain ACO1 by phenotypic characterization and 16S rRNA analysis. It showed a high capacity for bioemulsifier production and grew up to 60°C with NaCl at 180 g l -1 . The optimum NaCl concentration, pH and temperature for bioemulsifier production were 4% (w/v), 8.0, and 45°C, respectively. Although ACO1 did not utilize hydrocarbons, it had a high emulsifying activity (E 24 = 65 ± 5%) on different hydrophobic substrates. Emulsification was optimal while growing on yeast extract as the sole carbon source and NaNO 3 as the nitrogen source. The efficiency of the residual oil recovery increased by 22% after in situ growth of B. licheniformis ACO1 in a sand-pack model saturated with liquid paraffin.

- by Mohammad Amoozegar
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- Engineering, Technology, Biotechnology, Enhanced Oil Recovery

Sulfide accumulation due to bacterial sulfate reduction is responsible for a number of serious problems in the oil industry. Among the strategies to control the activity of sulfate -reducing bacteria ( SRB ) is the use of nitrate, which can exhibit a variety of effects. We investigated the relevance of this approach to souring oil fields in Oklahoma and Alberta in which water flooding is used to enhance oil recovery. SRB and nitrate -reducing bacteria ( NRB ) were enumerated in produced waters from both oil fields. In the Oklahoma field, the rates of sulfate reduction ranged from 0.05 to 0.16 M S day À 1 at the wellheads, and an order of magnitude higher at the oil -water separator. Sulfide production was greatest in the water storage tanks in the Alberta field. Microbial counts alone did not accurately reflect the potential for microbial activities. The majority of the sulfide production appeared to occur after the oil was pumped aboveground, rather than in the reservoir. Laborator...

- by Irene Davidova
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- Microbiology, Chemistry, Petroleum, Industrial Biotechnology

Many experimental investigations on carbonated water injection (CWI) have shown an increase in oil recovery which CWI is defined as the process of injecting CO 2-saturated water in oil reservoirs as a displacing fluid. In every enhanced oil recovery method, the potential formation damage of the injected fluid is considered. This is due to the fact that the injection of incompatible fluids often causes clay swelling and fines migration and thus impairs the formation permeability. Permeability reduction by clay particles mostly depends on its distribution which can be pore lining, pore bridging, dispersed or combination of these causing pore blocking or pore-throat diameter reduction. Besides, fine migration is considered as an important mechanism of recovery improvement during injection of low-salinity water in sandstone oil reservoirs. The present paper investigates the impact of injection of carbonated water and brines with the different salt concentrations on oil recovery and formation damage focusing on permeability variation. The investigation has been done on 12 relatively homogeneous clay-containing sandstone cores, while the compositions of the injection water were varied from 40,000 to 1000 ppm, at 176° F and 2000 psi. The amount of recovery improvement and permeability drop recorded in all tests and the fine effluent of two experiments were analysed using XRD, one for CWI and one for WF (water flooding). In all salinities, CWI has shown more oil recovery improvement than conventional water. CWI of 40,000 ppm showed the minimum permeability reduction of 6 percent, while the highest permeability was obtained by injection of water with 1000 ppm. Maximum ultimate oil recoveries of 61.2% and 42% were achieved by 1000 ppm both for CWI and WF, respectively. In comparison with brine injection, CWI resulted in more permeability drop in salinity above critical salt concentration (CSC), while below CSC, WF has caused more formation damage than CWI. Experimental results also showed that fine migration was the main reason behind formation damage. It was also revealed that permeability was significantly reduced due to fine production in the effluent.

- by Ehsan Yazdani Sadati and +1
- •
- Oil and gas, Enhanced Oil Recovery, CO2 emissions, Low Salinity Waterflooding

Baltic countries are located in the limits of the Baltic sedimentary basin, a 700 km long and 500 km wide synclinal structure. The axis of the syneclise plunges to the southwest. In Poland the Precambrian basement occurs at a depth of 5 km. The Baltic Basin includes the Neoproterozoic Ediacaran (Vendian) at the base and all Phanerozoic systems. Two aquifers, the lower Devonian and Cambrian reservoirs, meet the basic requirements for CO 2 storage. The porosity and permeability of sandstone decrease with depth. The average porosity of Cambrian sandstone at depths of 80-800, 800-1800, and 1800-2300 m is 18.6, 14.2, and 5.5%, respectively. The average permeability is, respectively, 311, 251, and 12 mD. Devonian sandstone has an average porosity of 26% and permeability in the range of 0.5-2 D. Prospective Cambrian structural traps occur only in Latvia. The 16 largest ones have CO 2 storage capacity in the range of 2-74 Mt, with total capacity exceeding 400 Mt. The structural trapping is not an option for Lithuania as the uplifts there are too small. Another option is utilization of CO 2 for enhanced oil recovery (EOR). The estimated total EOR net volume of CO 2 (part of CO 2 remaining in the formation) in Lithuania is 5.6 Mt. Solubility and mineral trapping are a long-term option. The calculated total solubility trapping capacity of the Cambrian reservoir is as high as 11 Gt of CO 2 within the area of the supercritical state of carbon dioxide.

- by Kazbulat Shogenov
- •
- Geology, Carbon Dioxide, Enhanced Oil Recovery, Sedimentary Basins

The article deals with the mechanism
of permeability reduction and methods
of impact on the rock in the bottomhole
formation zone. The change in the properties
of the bottomhole formation zone during injection
and production is shown; an estimation
of the state of the bottomhole formation
zone and the choice of the impact method
are given. The analysis of the technology of
reagent processing of the bottomhole formation
zone is carried out. Acid treatment of
producing wells and acid treatment of injection
wells are described.

- by solange barambonye
- •
- Enhanced Oil Recovery

The use of smart water has become the main priority for most oil companies due to significant benefits shown in various studies. The considerable potential of this method in increasing oil recovery along with the economic considerations has caused the study of smart water injection as an EOR method to have significant development. Smart water injection due to advantages such as low cost, availability, the possibility of use in different conditions (deep reservoirs and high-temperature reservoirs), the possibility of combining with other EOR methods (carbonate smart water, surfactant flooding, WAG, alkaline flooding, etc.), and good recovery potential has all the characteristics of an optimal EOR method. In this review, important and effective parameters and operating mechanisms for smart water injection in sandstone and carbonate reservoirs are briefly described.

- by Behnam ranjbar and +2
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- Enhanced Oil Recovery, Wettability Alteration, Low Salinity Waterflooding, chemical EOR
- by Dr. Mojtaba Rahimi
- •
- Enhanced Oil Recovery

There are primary, secondary and improved recovery methods that are developed according to the Field's needs, however, the primary recovery does not influence the increase of reservoir´s energy as the secondary and improved recovery does. Mature fields require such an increase in energy due to their production time, so water, gas or chemical injection methods also known as enhanced recovery methods (EOR) are required to satisfy the hydrocarbon demand of the moment.
This project search to quantitatively evaluate the implementation of a new enhanced recovery technology, such as the injection of silica nanoparticles, comparing it with conventional chemical recovery methods (Surfactant and Polymer) and thus determine its effectiveness and viability in the model sector of Yariguí-Cantagallo Field.

In this work, the performance of three natural surfactants (one produced by a bacteria and two of vegetal origin) in comparison to synthetics surfactants (cationic, anionic, non-ionic and zwitterionic) for its potential use in enhanced oil recovery EOR application was compared. The basis of comparison was basically the surfactant's solutions surface tension (ST) at room temperature, in the presence and absence of brine (salinity of about 4.7%). These measurements were developed to estimate if surfactants will resist reservoir conditions such as 75 °C and high salinities (up to 5%), conditions prevailing in the oil-field of Chicontepec, Veracruz (Mexico). Results of the work showed that biosurfactants could have potential for EOR process. The rhamnolipid produced by Pseudomonas and guar gum natural surfactants developed characteristics as good or even better than the synthetic surfactants normally employed in this process. The rhamnolipid produced by Pseudomonas seems to be a natural surfactant with extremely interesting characteristics. Rhamnolipid solutions yielded quite low ST at low concentrations (i.e. < 30 mN/m), even in the presence of brine for concentrations below 0.08%. Heat treatment applied to rhamnolipid solutions change very slightly the ST values when solutions contained no salts and about of 30% oil when brine was present. Rhamnolipid solutions did not show the higher foam capabilities, but represented half the capability of Polafix CAPB surfactant in producing foam. Neither guar nor locust bean gums showed important diminutions of ST at different concentrations in the solution. Nevertheless, for certain gum concentrations and in the presence of brine, guar gum had a very good performance (0.02%). Neither guar nor locust bean gums produced foam.► The Pseudomonas rhamnolipid is a natural surfactant with extremely interesting characteristics. ► For certain concentrations in the presence of brine, guar gum had a very good performance. ► Neither guar nor locust bean gums produced foam.

- by Luis Torres
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- Heat Treatment, Enhanced Oil Recovery, Affective Disorders, Room Temperature

Surfactants are amphiphilic compounds which can reduce surface and interfacial tensions by accumulating at the interface of immiscible fluids and increase the solubility, mobility, bioavailability and subsequent biodegradation of hydrophobic or insoluble organic compounds. Chemically synthesized surfactants are commonly used in the petroleum, food and pharmaceutical industries as emulsifiers and wetting agents. Biosurfactants produced by some microorganisms are becoming important biotechnology products for industrial and medical applications due to their specific modes of action, low toxicity, relative ease of preparation and widespread applicability. They can be used as emulsifiers, de-emulsifiers, wetting and foaming agents, functional food ingredients and as detergents in petroleum, petrochemicals, environmental management, agrochemicals, foods and beverages, cosmetics and pharmaceuticals, and in the mining and metallurgical industries. Addition of a surfactant of chemical or biological origin accelerates or sometimes inhibits the bioremediation of pollutants. Surfactants also play an important role in enhanced oil recovery by increasing the apparent solubility of petroleum components and effectively reducing the interfacial tensions of oil and water in situ. However, the effects of surfactants on bioremediation cannot be predicted in the absence of empirical evidence because surfactants sometimes stimulate bioremediation and sometimes inhibit it. For medical applications, biosurfactants are useful as antimicrobial agents and immunomodulatory molecules. Beneficial applications of chemical surfactants and biosurfactants in various industries are discussed in this review.

- by ajay singh
- •
- Engineering, Microbiology, Technology, Biotechnology

Chemical materials such as alkaline, surfactants, and polymers are widely used for the chemical EOR to reduce the trapped oil saturation in the reservoirs. Parameters such as surfactant adsorption and surfactant loss affect the performance of the mentioned EOR method. In this paper an attempt is made to enhance the performance of the surfactant flooding by application of nanoparticles. A series of core flooding tests were completed for sandstone core samples under reservoir conditions to study the effect of a novel application of nanoparticles to alter the properties of the surfactant in chemical flooding EOR processes. Sodium dodecyl sulfate (SDS) is widely used for the EOR approach. Silica nanoparticles were used to change the surfactant adsorption on the rock surfaces. The results showed that the addition of hydrophilic nanoparticles reduces the surfactant adsorption on the rock and improves the performance of the surfactant flooding which increases the oil recovery.

- by M.A Bagrezaie
- •
- Reservoir Engineering, Enhanced Oil Recovery, Surfactants, Silica Nanoparticles

This Ph.D. dissertation dealt with microbial enhanced oil recovery focusing on adaptation of bacteria to some of subsurface conditions and the mechanisms of enhanced oil recovery through the use of microbes and their metabolic products. The core of this thesis consists of eight articles mostly dedicated to combination of different chemical and physical laboratory methods for experimentation, analysis and interpretation. These include flow injection, fermentation process, chromatographic assay, spectroscopy and image analysis to provide new, simple and robust solutions to understanding of processes during microbial enhanced oil recovery. A review of microbial enhanced oil recovery was presented to better comprehend the problem. The importance of mathematical models used in predicting the structural and morphological of bacteria cells during adaptation stages has been qualitatively discussed. The roles of biogenic acids and gases in carbonate rock dissolution and re-pressurization during microbial fluid rock interactions were also highlighted. The adapted bacteria strain were tested in different in formation waters from the North Sea and also, evaluated for improvement in oil recovery from packed columns by injection of bacteria solution to mimic in-situ oil recovery. Paper I and II presents models that explain the relationships between environmental parameters of pH, electrical conductivity, salinity and gas dissolution based on simple empirical models. This is valuable for understanding some of the interactions in the subsurface during the enhance oil recovery. The measured salinity is similar to those found in oil reservoirs. Paper III gives an overview of the adapted strain of Clostridium tyrobutyricum. The main objective of this study was to investigate the growth and metabolic products capability of this adapted strain and the potential to enhance oil recovery at elevated salinity. It was elaborated that quantities of some of the metabolites, gas, acids and biofilms have direct relationships with salinity of the medium and recovery of 38 % from sandstone and 25 % from chalk was achievable. Paper IV-V highlighted the microbial fluid rock interactions. It was found that porosity increase observed in all the rock samples was mainly due to significant dissolution of carbonate by the organic acids produced during microbial metabolism. The patterns of dissolution lead to reduction in the bulk volume of the chalk samples. The pore volumes were slightly reduced or generally remain the same and the release of Ca 2+ ions into microbial medium. v mobilitet i forbindelse med en forøget olieudvinding. Analyseresultater har også vist at alkaner i olien bliver nedbrudt af overfladeaktive stoffer, som bliver fremstillet af bakterier. Resultater af denne afhandling vil forhåbentlig bidrage til den fortsatte udvikling af MEOR og finde anvendelse i både den tekniske, såvel i den industrielle sektor.

- by Simin Naghizadeh
- •
- Engineering, Environmental Science, Materials Science, Chemistry

This study evaluates the potential of carbon dioxide-enhanced oil recovery (CO2-EOR) to reduce greenhouse gas emissions without compromising oil production goals. A novel, dynamic carbon lifecycle analysis (d-LCA) was developed and used to understand the evolution of the environmental impact (CO2 emissions) and mitigation (geologic CO2 storage) associated with an expanded carbon capture, utilization and storage (CCUS) system, from start to closure of operations. EOR operational performance was assessed through CO2 utilization rates, which relate usage of CO2 to oil production. Because field operational strategies have a significant impact on reservoir engineering parameters that affect both CO2 storage and oil production (e.g., sweep efficiency, flood conformance, fluid saturation distribution), we conducted a scenario analysis that assessed the operational and environmental performance of four common and novel CO2-EOR field
development strategies. Each scenario was evaluated with and without stacked saline carbon storage, an EOR/storage combination strategy where excess CO2 from the recycling facility is injected into an
underlying saline aquifer for long-term carbon storage. The dynamic interplay between operational and environmental performance formed the basis of our CCUS technology analysis. The results showed that all CO2-EOR evaluated scenarios start operating with a negative carbon footprint and, years into the project, transitioned into operating with a positive carbon footprint. The transition points were significantly different in each scenario. Water-alternating-gas (WAG) was identified as the CO2 injection strategy with the highest potential to co-optimize EOR and carbon storage goals. The results provide an understanding of the evolution of the system’s net carbon balance in all four field development strategies studied. The environmental performance can be significantly improved with stacked storage, where a negative carbon footprint can be maintained throughout the life of the operation in most of the injection scenarios modeled. This information will be useful to CO2-EOR operators seeking value in storing more CO2 through a carbon credit program (e.g., the 45Q carbon credit program in the USA). Most importantly, this study serves as confirmation that CO2-EOR can be operationally designed to both enhance oil production and reduce greenhouse gas emissions into the atmosphere.

- by Vanessa Nunez-Lopez
- •
- Enhanced Oil Recovery, CCS, Energy transition, Life Cycle Assessment ( LCA )

The present study investigated the ability of a thermophilic anaerobic microbe (herein coded as AR80) for MEOR with the further objective to quantify the uncertainty of production forecast in terms of the cumulative probability distribution. A series of core flood experiments conducted in water-flooded Berea sandstone showed that up to 51% of initial oil-in-place was recovered when the plugs were treated with AR80 and shut-in for 14 days. Mainly, the oil recovery mechanisms were attributed to viscosity enhancement, wettability changes, permeability and flow effects. Matching the laboratory data using artificial intelligence: the optimized cumulative oil recovery could be achieved at an enthalpy of 894.2 J/gmol, Arrhenius frequency of 8.3, residual oil saturation of 20%, log of capillary number at microbe flooding stage of −1.26, and also depicted a history match error less than 3%. Therefrom, a sensitivity analysis conducted on reservoir shut-in period effect on oil recovery revealed that a relatively shorter shut-in period is recommended to warrant early incremental oil recovery effect for economical purposes. In addition, MEOR could enhance the oil recovery significantly if a larger capillary number (between 10−5 and 10−3.5) is attained. Per probabilistic estimation, MEOR could sustain already water-flooded well for a set period of time. This study showed that there is a 20% frequency of increasing the oil recovery by above 20% when a mature water-flooded reservoir is further flooded with AR80 for 2 additional years. Lastly, it was demonstrated herein that increasing the nutrient (yeast extract) concentration (from 0.1 to 1% weight) had less or no significant effect on the oil viscosity and subsequent recovery.

Research on the application of nanoparticles, specifically magnetic nanoparticles in enhanced oil recovery has been increasing in recent years due to their potential to increase the oil production despite having to interact with reservoirs of high salinity, high pressure and temperature and un-natural pH. Unlike other conventional EOR agents e.g. surfactants and polymers, a harsh environment will cause degradation and failure to operate. Magnetic nanoparticles which are activated by a magnetic field are anticipated to have the ability to travel far into the oil reservoir and assist in the displacement of the trapped oil. In this work, ferromagnetic Co 2+

- by Hassan Soleimani
- •
- Enhanced Oil Recovery, Electromagnetics

Fracture gradient of formation is a key to determine the casing setting depth in drilling oil/gas wells. In addition, for projects, such as hydraulic fracturing and enhanced oil recovery injection, knowing the fracture gradient of the injection zone is necessary. Also, the pressure integrity of the exposed open hole dictates the maximum allowed wellbore pressure. Several theoretical and operational methods for predicting fracture pressures have been developed and refined. A Leack-off test, which is the most reliable and common method for evaluating fracture pressure gradient, is performed by too much cost and time and also this test cannot be performed at several points. In the present article, a novel technique is presented to obtain an estimation of fracture pressure gradient from drilling operation data reports. This method is based on the effect of pore pressure and confining pressure on compressive strength of rock and, consequently, on drilling speed. Artificial neural networks were implemented to build a simulator for the rate of penetration and analyze the effect of hydrostatic pressure of wellbore on the rate of penetration. The presented method was performed on field data of an Iranian southern field and the results were satisfactorily close to the actual measured fracture pressure by an average error of about 1%.

- by R. Arabjamaloei
- •
- Enhanced Oil Recovery, Neural Network, Compressive Strength, Pore Pressure

Nowadays, due to the remarkable oil reduction in oil fields, enhanced oil recovery (EOR) techniques have been considered by a large number of scientists and company. Situ oil extraction is normally done by these techniques with high efficiency. In this particular study, five different surface active agents (surfactant), two kinds of oil with various API, two kinds of sulfonated polyacry-lamide, two different electrolyte solutions with various TDS and two distinctive alcohols were tested and evaluated. An optimal formulation in terms of the properties and quantity of materials has to be used in order to enhance oil recovery, achieved by investigation of surface tension and the phase behavior of mentioned substances. Rheological behavior of polymer flooding and surfactant was studied. Employing this formulation, the maximum micro emulsion of oil in water occurred. Due to the synergy between surfactant and alcohol (as a co-surfactant), relatively lower amounts of sur-factants were used which led to the dip in the cost of operation, and ultimately the efficiency of operation improved.

CO 2 solubility data in the natural formation brine, synthetic formation brine, and synthetic NaCl+CaCl 2 brine were collected at the pressures from 100 to 200 bar, temperatures from 323 to 423 K. Experimental results demonstrate that the CO 2 solubility in the synthetic formation brines can be reliably represented by that in the synthetic NaCl +CaCl 2 brines. We extended our previously developed model (PSUCO2) to calculate CO 2 solubility in aqueous mixed-salt solution by using the additivity rule of the Setschenow coefficients of the individual ions (Na + , Ca 2+ , Mg 2+ , K + , Cl − , and SO 4 2− ). Comparisons with previously published models against the experimental data reveal a clear improvement of the proposed PSUCO2 model. Additionally, the path of the maximum gradient of the CO 2 solubility contours divides the P-T diagram into two distinct regions: in Region I, the CO 2 solubility in the aqueous phase decreases monotonically in response to increased temperature; in region II, the behavior of the CO 2 solubility is the opposite of that in Region I as the temperature increases.

- by Yee Soong
- •
- Engineering, Earth Sciences, Climate Change, High Pressure

Surfactants are widely used for various purposes in industry, but for many years were mainly chemically synthesized. It has only been in the past few decades that biological surface-active compounds (biosurfactants) have been described. Biosurfactants are gaining prominence and have already taken over for a number of important industrial uses, due to their advantages of biodegradability, production on renewable resources and functionality under extreme conditions; particularly those pertaining during tertiary crude-oil recovery. Conflicting reports exist concerning their efficacy and the economics of both their production and application. At present, their uses are mainly in the oil and petroleum industries, where they are employed primarily for their emulsification capacity in both tertiary recovery and polluted-sites remediation. However, caution is frequently exercised with respect to their use because of possible subsequent microbial contamination of either underground oil reservoirs or products. The limited successes and applications for biosurfactants' production, recovery, use in oil pollution control, oil storage tank clean-up and enhanced oil-recovery are reviewed from the technological point of view.

- by wael ali
- •
- Bioremediation, Enhanced Oil Recovery, Multidisciplinary, Biodegradation

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- by Alexander Rozhko and +1
- •
- Geophysics, Rock Mechanics, Geomechanics, Multiphase Flow
- by Mingzhen Wei
- •
- Chemical Engineering, Enhanced Oil Recovery, Reservoir Simulation

Petroleum resources continue to dominate the energy sectors with no sign of a decline. Petroleum reserves, however, are dwindling in view of fewer new discoveries and increased production level. It is important to determine petroleum reserves accurately in order to correctly forecast energy budget in the future. The most commonly used methods to describe the fluid flow in oil reservoirs employ constant rock properties. However, these methods are not applicable to reservoirs that undergo changes in the rock properties due to variation in pore pressure. Common characteristics of fractured reservoirs are sensitivity of permeability and porosity to effective stress. The in-situ stress, in itself, can be of mechanical or thermal origin. The thermal stress can be significant in thermal enhanced oil recovery schemes such as injection of cold fluid in hot formation during water flooding or wastewater disposal, or even during hydraulic fracturing. Unfortunately, the most commonly literature review reveals that the research in this area has been focused mainly on thermal recovery of heavy oil. Few investigation, however, have been done on the onset and propagation of fractures under thermal stress or mechanical stress. Consequently, this paper is devoted to investigate fracture development and propagation in carbonate formation under thermal and mechanical stress. A series of experiments were ingeniously designed to study the effect of thermal stress on fractured carbonate formation. Laboratory experiments were conducted to determine stress-strain relationship and the time dependence taking in account fracture formations and their propagation. A computer image analyzer was used to observe the fracture/fissures distribution for various cases of thermal stress on carbonate rocks. The role of thermal and mechanical stress in determining orientation and propagation of fractures was also studied.

- by Rafiq Islam and +1
- •
- Thermal Engineering, Thermodynamics, Enhanced Oil Recovery, Petroleum Engineering

A newly developed, multistage quick-look methodology allows for the efficient screening of an unmanageably large number of reservoirs to generate a workable set of sites that closely match the requirements for optimal CO 2 enhanced oil recovery (EOR) storage. The objective of the study is to quickly identify miscible CO 2 EOR candidates in areas that contain thousands of reservoirs and to estimate additional oil recovery and sequestration capacities of selected top options through dimensionless modeling and reservoir characterization. Quick-look assessments indicate that the CO 2 EOR resource potential along the US Gulf Coast is 4.7 billion barrels, and CO 2 sequestration capacity is 2.6 billion metric tons. In the first stage, oil reservoirs are screened and ranked in terms of technical and practical feasibility for miscible CO 2 EOR. The second stage provides quick estimates of CO 2 EOR potential and sequestration capacities. In the third stage, a dimensionless group model is applied to a selected set of sites to improve the estimates of oil recovery and storage potential using appropriate inputs for rock and fluid properties, disregarding reservoir architecture and sweep design. The fourth stage validates and refines the results by simulating flow in a model that describes the internal architecture and fluid distribution in the reservoir. The stated approach both saves time and allows more resources to be applied to the best candidate sites.

Surfactants have all along been used to reduce the interfacial tension (IFT) between oil and water to overcome the trapping phenomena that causes about 65% of the crude oil to be trapped after the primary and secondary recovery. The costs of surfactants on the other hand derived from petroleum-based source are costly. In this study, lignin was extracted from black liquor obtained by pulping local oil palm and coconut fiber and mixing it with amine and Sodium Dodecyl Sulfate (SDS) to form surfactant formulation for application in surfactant flooding experiments. Three formulations from each lignin with lowest IFT were evaluated for their performance in remobilizing residual oil recovery through oil displacement experiments using glass bead packed model at room temperature. For the formulation containing oil palm lignin, the forth formulation (SDBS-E4) gives the highest oil recovery (4.10 % of original oil in place) and the formulation from coconut fiber, the fifth formulation (SDBS-C5) gives the second highest oil recovery (3.30 % of original oil in place). The results show that lignin based surfactants have a good potential to recover oil.
Key words: Black liquor, oil palm, coconut fiber, lignin, surfactant, enhanced oil recovery

- by Sagala Fahad
- •
- Enhanced Oil Recovery

Previous works based on statistical design of experiments (DoE) defined a model all-alumina self-flow refractory castable (SFRC) with optimized particle size distribution for simultaneous high flowability index (FI) and superior post-sintering performance. This work compares the SFRC rheological behaviour and setting time with those of alternative all-alumina castables with different Andreasen aggregate particle size distribution modulus, and of the equivalent castables containing calcium aluminate cement. The model castable showed Bingham behaviour with low yield stress, viscosity and thixotropy, guaranteeing easier casting and less wear in the casting and/or projection equipment. However, as the coarse particle fraction increases, the castable flow tends to be non-linear and changes from Bingham to Herschel-Bulkley. The cement containing castables quickly loose flowability despite the applied shear. This work confirmed previous conclusions based on FI measurements and demonstrates the adequacy of the use of FI values in the calculation of FI response surface by DoE.

Lubricating oils are viscous liquids used for lubricating moving part of engines and machines. Lubricating oils are obtained from petroleum a finite product and with dwindling production from world oil reserves, is essential to recognize that all used oils should be collected for controlled disposals. Some products such as transformer oils and hydraulic oils, can be readily collected from large industrial concerns, regenerated to a recognized standard and returned to original source. Oil from automotive sources will include mono and multi-grade crankcase oils from petrol and diesel engines, together with industrial lubricants that have been inadequately segregated may also be included. Lubrication oil is used to provide a film between the moving parts of machines and engines to prevent wear with little or no loss of power.

- by Kirti Zare and +1
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- Chemical Engineering, Petroleum, Oil and gas, Lubrication

Nigeria is gradually advancing into the secondary stage of oil recovery, necessitating preparation for tertiary oil recovery especially enhanced oil recovery (EOR). Considering the high cost of EOR agents, it is imperative to investigate the performance of available local EOR agents against foreign agents when these agents (such as surfactants and polymers) are used in combination. Oil displacement experiments were thus conducted using foreign and local surfactant-polymer (SP) and alkaline-polymer (AP) agents on Nigerian crude and their results were compared. The experiments entailed using different percentage ratios of surfactants to polymers and alkaline to polymer. Four kinds of Alkaline were also used to displace residual oil from sand to find out what type of alkaline displaces oil better. The displacement efficiencies obtained from experimental results showed that the foreign EOR agents performed better than the local EOR agents. For the SP agents, the foreign SP displaced above 90% of both light and medium crude at about 45/55 percentage and 0/100 percentage respectively. The local SP displaced a maximum of about 35% of the light crude and 75% of medium crude at an SP ratio of about 20/80 for both cases. The use of Alkaline-Polymer results showed that the foreign agents performed better than the local agents. The maximum displacement efficiency of the foreign AP was 78.13% at a ratio of 40/60 while the maximum displacement efficiency of the local AP was 64% at a ratio of 60/40. The displacement of residual oil experiments performed using four kinds of alkaline showed that potassium hydroxide (KOH) enhances recovery better than NaOH, Na 2 CO 3 and Palm bunch ash (a local source of alkaline). It was also observed that oil displacement efficiency increased as pH value of the alkaline increased.

Many reservoir engineers are facing a major challenge in the best technique of producing very large oil reserves. Some of the common techniques employed to effect high productivity are the development and use of EOR methods and giant... more

- by abhishek patwardhan
- •
- Reservoir Engineering, Enhanced Oil Recovery
- by Dr. Abdulmohsin Imqam (Professor)
- •
- Enhanced Oil Recovery

With the decline in oil discoveries during the last decades it is believed that EOR technologies will play a key role to meet the energy demand in years to come. This paper presents a comprehensive review of EOR status and opportunities to increase final recovery factors in reservoirs ranging from extra heavy oil to gas condensate. Specifically, the paper discusses EOR status and opportunities organized by reservoir lithology (sandstone and carbonates formations and turbiditic reservoirs to a lesser extent) and offshore and onshore fields. Risk and rewards of EOR methods including growing trends in recent years such as CO 2 injection, high pressure air injection (HPAI) and chemical flooding are addressed including a brief overview of CO 2 -EOR project economics.

- by Gemilang Aditya
- •
- Enhanced Oil Recovery, CO2, EOR, Steam Injection

In Ecuador, the fields are getting more challenging in terms of reservoir depletion. Inchi field is an example of such a field in which the production is normally obtained using electric submersible pumps (ESP), with a fast production decline. The wells start with production rates of 1,000 BOPD, and immediately production and pump intake pressure begin to decrease, thus requiring a secondary recovery technique such as water injection. However, the water to inject at required pressure is not always available, andspecial facilities are required to execute this operation, which increasescapital expenditures (CAPEX). Using a new approach that used the advantages of ESP sensors and operational flexibility, a production well was selected and converted to an injection well thus avoiding the high investments in surface facilities and making the secondary recovery a feasible option for low-producing wells. The Inchi A8 well on the Inchi A pad, was converted toa production injection well due to lack of available water in the field and production facilities. The paper includes an analysis of the completion design, ESP design, sensor installation modification for real-time injection pressure monitoring, ESP performance, injection stimulation, and results with the performance analysis for production recovery of nearby wells. The experience shared in this paper will let the reader understand the challenges for installation of a production injection well driven by the specific needs for and the advantages of injection pressure monitoring. After the installation of the production injection completion, the decrease in production and reservoir pressure stopped, the production in the field increased up to 166 BFPD in the Inchi 01 and Inchi A5 wells, the flowing bottomhole pressure has increased inan average of 100 psi in the wells Inchi 01 and Inchi A5, and in the well Inchi B6 the flowing bottomhole pressure is steady now closed to 600 psi (before was constantly decreasing). The injection pressure monitoring has been useful especially during the injection pressure tests performed by a testing unit, which allows to check the actual injection index of the reservoir. The savings associated with the installation of the production injection well include eliminating the need for additional surface facilities, a pipeline to bring water from the main station, and the construction of the water treatment plant in the location.

- by Diego Cueva
- •
- PRODUCTION ENGINEERING, Enhanced Oil Recovery, Artificial Lift System

Surfactants have already been distinguished as having commercial application in oil industry especially Enhanced Oil Recovery (EOR) processes. During EOR processes, surfactants or a mixture of surfactants and polymers are injected into the reservoir to reduce the interfacial tension of microemulsion typically from about 30 dyn/cm to 10 −3 dyn/cm. Polymers are added to reduce the mobility by increasing the viscosity of the solution. The geometrical micelle shape of a number of surfactants might change from spherical to cylindrical above a concentration generally known as critical micelle concentration. Although previous studies haven't considered the effect of surfactants on solution viscosity, this shape transition could significantly affect the viscosity of solution. In this study, a previously developed model is used in conjunction with experimental data to investigate the effect of surfactant and salt concentrations on the micelle shape transition. It is found that for some ranges of surfactant and salt concentrations; shape transition from spherical to cylindrical causes a considerable increase in the viscosity of dodecyl ammonium chloride (DeAC) solution. Based on the results of this study, a number of surfactants could be used for simultaneous modification of the IFT and viscosity of the microemulsion rather than using both polymers and surfactant.

- by peyman kamranfar
- •
- Enhanced Oil Recovery, Microemulsions, chemical EOR, Petroleum Engineering

An overview of the enormous potential for increasing oil production in Trinidad's oilfields which are mostly depleted. Currently percentage of OOIP is only 25% or so and a further 3.5 million barrels are recoverable using CO2 and other... more

- by Krishna Persad
- •
- Enhanced Oil Recovery

— Oil exploration has enormous economic benefits; however, these benefits are associated with environmental issues arising from oil spills. Numerous methods exist for cleaning up oil spills along with their after-effect as well as huge financial burden. Hence, the shift to methods that are environmentally friendly and cost effective is imperative. This paper investigates the efficiency and mechanics of using human hair to clean up crude oil contaminated water using various parameters such as contact time, recovery and reuse, adsorbent dosage, temperature, modification. Human hair has proven to be an efficient material in removing oil from water with a maximum adsorption capacity of 7470mg/g for crude oil as well as its recovery and reusability. Investigation reveals that African hair came first, followed by Asian hair and finally, European hair with an adsorption capacity of 7470, 6176 and 5246mg/g for crude oil respectively. The result obtained for the kinetics of adsorption revealed a good fit in pseudo-second order model, indicating that the mode of adsorption is exothermic which is controlled by a chemisorption process. The isotherm studies also revealed that the experimental data is better described with Freundlich isotherm model. A comparative analysis conducted using the maximum adsorption capacity of different adsorbents revealed that human hair performed better than organoclay, rice husks, reed bed canary grass, treated sludge, modified oil palm leaves, peat moss and activated carbon, but less than exfoliated graphytes, kapot and recycled wool based non-woven material. Hence, human hair can be modified into boom to clean-up oil spills. This is a promising area that researchers need to focus more on inorder to explore the huge benefits it presents.

- by Akpevwe K idogun and +2
- •
- Nanoparticles, Enhanced Oil Recovery, Oil Spill, Oil Spills in the Marine Environment

EOR theory for gas and water flooding

- by Charles Hing
- •
- Enhanced Oil Recovery, Waterflooding

This report provides a summary of the work performed in this 3-year project sponsored by DOE. The overall objective of this project is to identify new, potentially more costeffective surfactant formulations for improved oil recovery (IOR). The general approach is to use an integrated experimental and computational chemistry effort to improve our understanding of the link between surfactant structure and performance, and from this knowledge, develop improved IOR surfactant formulations.

- by Stefan Iglauer
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- Computational Chemistry, Economics, Performance, High Energy Density Physics

Petrobras’ program for enhanced oil recovery (PRAVAP - Programa de Recuperação Avançada de Petróleo)
recognizes that the current world exploratory scenario is one of ever scarcer discoveries and more mature
fields. MEOR (microbial enhanced oil recovery), the technology which involves the use of microorganisms for
the recovery of additional petroleum from existing reserves, is well developed, and today there exist several
examples of successful applications in mature fields, in wells with high viscosity oil, and in reservoirs with low
permeability or other flow problems. This technology seeks to take advantage of effects which occur at the
molecular level, and which induce modifications in the structure of the reservoir matrix or in the oil itself, in
order to ease its flow and consequent production. Given the economic dimension of the oil industry, MEOR
exhibits a strategic importance for any country with the possibility of applying this technology to increase its
oil production or reserves. This recognition has been demonstrated by several companies and several
countries which have applied MEOR, and which continue to carry out studies to better understand its
potential and the operating principles behind it. The advent of MEOR represents a strategic opportunity to
dominate a leading edge technology and establish leadership in a technological field with potential and
importance similar to those involved in the know-how of deep water oil exploration and production.

- by Hernani Chaves and +2
- •
- Chemical Engineering, Enhanced Oil Recovery, Petroleum Biotechnology

Oil fields offer a significant potential for storing CO 2 and will most likely be the first large scale geological targets for sequestration as the infrastructure, experience and permitting procedures already exist. The problem of co-optimizing oil production and CO 2 storage differs significantly from current gas injection practice due to the cost-benefit imbalance resulting from buying CO 2 for enhanced oil recovery projects. Consequently, operators aim to minimize the amount of CO 2 required to sweep an oil reservoir. For sequestration purposes, where high availability of low cost CO 2 is assumed, the design parameters of enhanced oil recovery processes must be redefined to optimize the amount of CO 2 left in the reservoir at the time of abandonment. To redefine properly the design parameters, thorough insight into the mechanisms controlling the pore scale displacement efficiency and the overall sweep efficiency is essential. We demonstrate by calculation examples the different mechanisms controlling the displacement behavior of CO 2 sequestration schemes, the interaction between flow and phase equilibrium and how proper design of the injection gas composition and well completion are required to co-optimize oil production and CO 2 storage.

Chemical flooding has been found to be one of the major EOR
techniques especially for reservoirs where thermal methods are not feasible.
The application of chemical flooding is strongly influenced by the current
economics, type of reserve oil and crude oil price. In this paper, an up to
date status of chemical flooding at the laboratory scale, pilot projects and
field applications have been reported. The basic mechanisms of different
chemical methods have been discussed including the interactions of
different chemicals with the reservoir rocks and fluids. The average recovery of
oil after the conventional water flooding is highly encouraging particularly
when the demand and price of crude oil is increasing day by day.

- by Ajay Mandal
- •
- Enhanced Oil Recovery