Carbon dioxide(CO2) geosequestration in deep saline aquifers has been currently deemed as a preferable and practicable mitigation means for reducing anthropogenic greenhouse gases(GHGs) emissions to the atmosphere, as...Carbon dioxide(CO2) geosequestration in deep saline aquifers has been currently deemed as a preferable and practicable mitigation means for reducing anthropogenic greenhouse gases(GHGs) emissions to the atmosphere, as deep saline aquifers can offer the greatest potential from a capacity point of view. Hence,research on core-scale CO2/brine multiphase migration processes is of great significance for precisely estimating storage efficiency, ensuring storage security, and predicting the long-term effects of the sequestered CO2in subsurface saline aquifers. This review article initially presents a brief description of the essential aspects of CO2subsurface transport and geological trapping mechanisms, and then outlines the state-of-the-art laboratory core flooding experimental apparatus that has been adopted for simulating CO2injection and migration processes in the literature over the past decade. Finally, a summary of the characteristics, components and applications of publicly reported core flooding equipment as well as major research gaps and areas in need of further study are given in relevance to laboratory-scale core flooding experiments in CO2geosequestration under reservoir conditions.展开更多
This paper introduces the results of selecting and breeding a micro-organism, Strain I, and its core model experiment investigation for microbial enhanced oil recovery (MEOR). Strain I was separated from the formation...This paper introduces the results of selecting and breeding a micro-organism, Strain I, and its core model experiment investigation for microbial enhanced oil recovery (MEOR). Strain I was separated from the formation water of the Dagang oil field, with analytical results showing that Strain I is a gram-positive bacillus. A further study revealed that this strain has an excellent tolerance of environmental stresses: It can survive in conditions of 70℃, 30 wt% salinity and pH3.5-9.4. Strain I can metabolize biosurfactants that could increase the oil recovery ratio, use crude oil as the single carbon source, and decompose long-chain paraffin with a large molecular weight into short-chain paraffin with a small molecular weight. The core model experiment shows that Strain I enhances oil recovery well. Using 2 vol% of the fermentation solution of Strain I to displace the crude oil in the synthetic plastic bonding core could increase the recovery ratio by 21.6%.展开更多
A common assertion is that alkaline solution aids oil mobilization by generating in situ soap,or by lowering interfacial tension(IFT)to ultra-low values in synergy with surfactants.This study takes a different approac...A common assertion is that alkaline solution aids oil mobilization by generating in situ soap,or by lowering interfacial tension(IFT)to ultra-low values in synergy with surfactants.This study takes a different approach that involves the alkaline dissolution of detrital quartz grains of sandstone reservoirs to create pathways for oil migration and accumulation.Quartz dissolution via alkaline injection will result in changes in permeability and porosity.This study performed high-pH core flooding on Berea sandstones using core displacement equipment.Silica molybdate spectrophotometry was applied to measure the amount of dissolved silica.Inlet and confining pressure variations were also observed.The molar concentration of NaOH varied at 0.5 M and 1.0 M.The results show higher initial silica dissolution for 0.5 M NaOH(˃200mg/L)compared to 1.0 M NaOH(20 mg/L),which can be attributed to the presence of pre-existing dissolved silica and precipitates in the system prior to the first injection phase.Nonetheless,a steady quartz dissolution rate of 0.4 mg/L/hr for 20 h was only achieved at 1.0 M.Conversely,an abrupt drop in quartz dissolution to below 0 mg/L was recorded for 0.5 M NaOH after 3 h of dissolution.At higher molar concentration of injected alkaline solution,both confining and inlet pressures increased from 8 and 5 bars to 12 and 11 bars as a result of the increased secondary phase of(hydr)oxides or precipitates in the pores.Thus,it can be inferred that the effect of alkaline solution on quartz dissolution is strongly dependent on molar concentration.展开更多
Despite advances in renewable energy sources, the world's current infrastructure and consumption patterns still heavily depend on crude oil. Enhanced oil recovery(EOR) is a crucial method for significantly increas...Despite advances in renewable energy sources, the world's current infrastructure and consumption patterns still heavily depend on crude oil. Enhanced oil recovery(EOR) is a crucial method for significantly increasing the amount of crude oil extracted from mature and declining oil fields. Nanomaterials have shown great potential in improving EOR methods due to their unique properties, such as high surface area, tunable surface chemistry, and the ability to interact at the molecular level with fluids and rock surfaces. This study examines the potential use of incorporating ethoxylated molybdenum disulfide with a unique three-dimensional flower-like morphology for overcoming the challenges associated with oil recovery from reservoirs characterized by complex pore structures and low permeability. The synthesized nanomaterial features a chemical composition that encompasses a polar ethoxy group linking molybdenum disulfide nanosheets and an alkylamine chain. The ethoxy group promotes interactions with water molecules through hydrogen bonding and electrostatic forces, disrupting the cohesive forces among water molecules and reduction surface tension at the oil-water interface. As a result, the nanomaterial achieves an ultra-low interfacial tension of 10^(-3) mN/m. Core flooding experiments demonstrate a significant oil recovery of approximately 70% at a concentration as low as 50 ppm. This research paves the way for the design and synthesis of advanced extended surfactant-like nanomaterials,offering a promising avenue for enhancing oil recovery efficiency.展开更多
The main advantages of the use of ionic liquids in enhanced oil recovery are their tunability and stability in harsh environmental conditions. In this work, a comprehensive review of ionic liquids proposed to improve ...The main advantages of the use of ionic liquids in enhanced oil recovery are their tunability and stability in harsh environmental conditions. In this work, a comprehensive review of ionic liquids proposed to improve current chemical oil recovery methods has been presented, focusing on core flooding experiments. With an almost infinite number of possible ionic liquids, the amount of experiments carried out up to now has been very limited. However, results are promising, with additional recovery after secondary flooding of up to 32% of the original oil in place. Most formulations with ionic liquids have been proposed for sandstone reservoirs, the number of studies with carbonate cores being very scarce. The possibilities of a new room temperature surface active ionic liquid, 1-decyl-3-methylimidazolium triflate,for this application were analyzed. It was shown that it is able to drastically reduce the water/oil interfacial tension. An optimized formulation was proposed for carbonate reservoirs. After secondary flooding with brine, an additional recovery of 10.5% of original oil in place was achieved at room conditions. A combination of the proposed method followed by a polymer flooding step with polyacrylamide led to a lesser but still significant recovery, reducing the costs associated to the ionic liquid.展开更多
To recover oil from brownfields,test air booster chemical flooding.Silica nanoparticle-polymer Arabic gum(SP)solution injection with controlled air injection is studied for displacement efficiency synergy.Multiple cru...To recover oil from brownfields,test air booster chemical flooding.Silica nanoparticle-polymer Arabic gum(SP)solution injection with controlled air injection is studied for displacement efficiency synergy.Multiple crude oil-soaked core samples were employed in lab core flooding procedures to approximate reservoir conditions.Performance depended on pressure drop,burst duration,and oil recovery.Study:continuous oxygen air flooding eliminates less oil from the ground than AAW.Results from experiments supported this.Air alternative water(AAW)optimises oil recovery and efficiency by regulating flow.In congested reservoirs,air can replace water.Constant air sealing keeps oil from water.Air alternative water(AAW)systems use polymers like Arabic gum,silica nanoparticles,and a mix of the two to remove oil and prevent water contamination.Nano-polymer-alternating-water(NPAW)creates air alternate water(AAW).Three-phase flow with silica and Arabic gum is studied in this study.A two-phase investigation used combination,silica,and polymer/oil.Water/oil and combination/oil displacement boosted oil output and relative permeability,unlike polymer/oil and nanoparticles.Air and oil have lower surface resistance than water.Air injection sweeps outperform water floods technically.Lab scientists analyse chemical fluid-oil interfacial tension with polymer-silica and NaCl.Air,fluid,and fluid injections recovered 48.6%,20%,and 16.7%of oil in core flooding testing.This reveals that air,Arabic gum,and silica nanoparticles greatly improve lab core oil recovery.The air boosters increased oil flow,residual saturation,and sweep.Chemicals and air injection improve older deposit EOR.展开更多
Different methods of enhanced oil recovery have been used to produce trapped oil.One of these methods is carbonated water injection in which CO2 contained water is injected in reservoirs in order to decrease free CO2 ...Different methods of enhanced oil recovery have been used to produce trapped oil.One of these methods is carbonated water injection in which CO2 contained water is injected in reservoirs in order to decrease free CO2 injection mobility,increase water viscosity and store/remove produced greenhouse CO2 gas safely.Another enhanced oil recovery method is smart water injection at which the ions in brine are modified in order to make controlled reactions with distributed ions on the surface of rock to cause more hydrocarbon recovery.Therefore,combination of these two methods may also have a great effect on enhancing oil recovery or may result in recovery factor less than each method used alone.In this paper hybrid smart carbonated water injection method is investigated to study its applicability in oil recovery using core flooding setup.The experimental core flooding setup was designed to perform different types of EOR methods for the sake of recovery comparison with the new hybrid method.The effect of both brine content and volume of CO2 is determining in hybrid EOR assessment.The main findings of this work show that the hybrid smart carbonated water results in the highest recovery factor in comparison to the most well-known EOR methods for carbonate cores.展开更多
Advancing the use of natural surfactants in enhanced oil recovery is crucial for sustainable practices in the oil and gas industry.This research assesses the applicability of neem-derived natural surfactants in offsho...Advancing the use of natural surfactants in enhanced oil recovery is crucial for sustainable practices in the oil and gas industry.This research assesses the applicability of neem-derived natural surfactants in offshore fields,encompassing surfactant synthesis via saponification,characterization through FT-IR,SEM,and EDS,and measuring surface and interfacial tension across various conditions.Adsorption studies determined the surfactant's adsorption characteristics onto rock,and core flooding tests assessed its efficacy.Surface tension measurements in deionized water(DIW)and brine confirmed the surfactant's surface activity.As the concentration increased from 1 wt%to 6 wt%,the interfacial tension(IFT)significantly decreased from 22.5 mN/m to 7.9 mN/m,marking a 64.8%reduction.Additionally,surfactants formed micelles more efficiently in saline water,with the critical micelle concentration(CMC)dropping from 4.0 wt%in DIW to 0.9 wt%.Adsorption on limestone showed over 50%higher adsorption than sandstone,confirming stronger interactions and higher adsorption saturation.Core flooding experiments demonstrated the surfactant's effectiveness in oil and water-wet conditions.When injected into sandstone,the surfactant achieved a significant additional oil recovery of 24.6%in deionized water,compared to 10.2%in limestone.Conversely,in saline conditions,the surfactant's performance was better in limestone,achieving an additional recovery of 4.9%,whereas in sandstone,it was only 1.6%.This research offers a unique perspective on how natural surfactants perform across different rock types.The findings suggest that neem-derived surfactants hold significant promise for enhancing oil recovery in Kazakhstan's oil fields.展开更多
Enhanced oil recovery(EOR)methods are essential for optimizing oil extraction from modern reservoirs.This research delved into the synergistic impact of combining anionic and nonionic surfactant mixtures with silica(S...Enhanced oil recovery(EOR)methods are essential for optimizing oil extraction from modern reservoirs.This research delved into the synergistic impact of combining anionic and nonionic surfactant mixtures with silica(SiO_(2))nanoparticles(NPs)in sodium chloride(NaCl)solutions,alongside the added enhancement of polymers,to improve crude oil recovery.The study comprehensively evaluated stability,rheological characteristics,interfacial tension(IFT)behavior,wettability alterations,and EOR experi ments using mixtures of sodium dodecyl sulfate(SDS)and triton X-100(TX-100)surfactants.Scenarios both with and without SiO_(2)NPs in a base solution containing 3000 ppm NaCl and 2000 ppm xanthan gum(XG)polymer were examined.Core flooding tests were carried out on San-Saba sandstone core specimens with low permeability.The stability tests and dynamic light scattering(DLS)analysis were performed to assess the stability of NPs in low saline-surfactant-polymer solution.It was observed that NPs significantly reduced the IFT between the test solutions and crude oil,with nanofluids exhibiting satisfactory stability at a 0.4 wt%SiO_(2)NPs concentration.Core flooding studies demonstrated a syner gistic interaction between NPs and the binary surfactant-polymer mixture,resulting in substantially greater incremental recovery of oil in comparison with the case of using binary surfactant-polymer combination alone.The mechanisms contributing to EOR with nanofluids,such as IFT reduction and wettability alteration,were explored.Incorporating NPs at concentrations of 0.1,0.2,and 0.4 wt%led to incremental oil recoveries of 4.01%,12.35%,and 12.73%of the original oil in place(OOIP),respectively,as opposed to the recovery achieved using only SDS+TX-100+XG.Consequently,these findings advance the understanding of the potential application of SiO_(2)NPs in combination with the binary surfactant polymer mixture as effective chemical EOR agents.Additionally,these insights aid in identifying suit able sandstone reservoirs for nanofluid application,contributing to the optimization of oil recovery strategies.展开更多
This research examines the impact of wettability alteration on the end points of relative permeability,a crucial property of fluids and porous media that influences the displacement processes of immiscible fluids thro...This research examines the impact of wettability alteration on the end points of relative permeability,a crucial property of fluids and porous media that influences the displacement processes of immiscible fluids through such media.The estimation of the mobility ratio for oil recovery relies on these end points,which are influenced by connate water saturation and residual oil saturation.To investigate this relationship,carbonate rock is generally subjected to wettability alteration using surfactant agents,and core flooding is employed to determine the relative permeability before and after the alteration.The wettability of the rock is commonly assessed through contact angle measurements.Two surfactants,TritonX-100(Tx-100)and Cedar,were tested in reducing the wettability of the porous media for oil.The contact angle measurements revealed that Tx-100 was more effective for this purpose than Cedar.Furthermore,the relative permeability tests indicated that both surfactants decreased residual oil saturation,but Tx-100 also improved system pressure.In contrast,Cedar reduced residual oil saturation but increased system pressure,possibly because of its high viscosity.The results also demonstrate that injecting Tx-100 leads to a 14%increase in ultimate oil recovery compared with water injection,while Cedar injection increased the recovery factor by 5%.This difference may be attributed to the incomplete coverage of the pore wall by Cedar or its weaker chemical structure than Tx-100.Notably,in carbonate cores,neither non-ionic surfactant enhanced oil recovery.展开更多
Matrix acidizing is usually conducted on sandstone reservoirs to increase hydrocarbon production.Mineralogy plays an important role in designing acidizing treatments to enhance the production of oil and gas from sands...Matrix acidizing is usually conducted on sandstone reservoirs to increase hydrocarbon production.Mineralogy plays an important role in designing acidizing treatments to enhance the production of oil and gas from sandstone reservoirs.The most common acid in practice to acidize sandstone formation is mud acid after the pre-flush acid stage.The main aim of the pre-flush acid stage is to dissolve positive ions like calcium,potassium,sodium,etc,which can cause precipitation reactions during the mud acid stage.This research is aimed to investigate the reaction mechanism of a new pre-flush acid combination(hydrochloric acid and acetic acid)with sandstone formation.Core flooding experiments were performed to react acid with the core samples(6 in×1.5 in)under high pressure and temperature(HPHT)condi-tions(80℃and 1000 psia).Analytical techniques such as Tescan Integrated Mineral Analysis(TIMA)have been used to illustrate the effect of these acids on sandstone formation.TIMA analysis showed that the new acid combination was effective in dissolving various minerals(ankerite,magnetite)and cations(calcium,magnesium,sodium,and iron).15%HCl proved to be more effective in the dissolution of different particles from sandstone core samples.It dissolved 32.8%of the initial number of particles present inside the sample while the dissolving power of 5%CH_(3)COOH:10%HCl is 26.7%.Subsequently,the number of pores increased by the application of 15%HCl is 22%while that by 5%CH_(3)COOH:10%HCl is 21.8%.Density analysis showed that both acid combinations removed heavy particles effectively,whereas 5%CH_(3)COOH:10%HCl proved more efficient in dissolving calcium ions which is very important for pre-flush acidizing.展开更多
This study explores the effectiveness of alcohol injection as a stimulation treatment to mitigate water blockage in the vicinity of the wellbore.Over the years,water blockage has emerged as a recurring challenge withi...This study explores the effectiveness of alcohol injection as a stimulation treatment to mitigate water blockage in the vicinity of the wellbore.Over the years,water blockage has emerged as a recurring challenge within the oil and gas industry,leading to diminished well productivity.In a commingled reservoir with multiple layers,when a producing well is shut-in for well intervention or workover,water may encroach from water zones into the oil-bearing formations through the wellbore due to pressure differences between the layers.Water encroachment can have a significant impact on the production of a well.It can reduce the oil production rate,increase the water cut,and shorten the well's lifespan.Therefore,it is essential to take steps to mitigate the water encroachment effect in commingled reser-voirs.This study explores the use of alcohol injection to reduce transition time and remediate formation damage in commingled oil reservoirs.Limited studies have shown that alcohol has the potential to enhance fluid relative Permeability in gas condensate reservoirs and reduce condensate banking near the wellbore.However,this approach has not yet been tested in commingled oil reservoirs.A series of core flooding tests were conducted using Berea sandstone cores and a Texan light crude oil sample.The core flood setup was designed to represent the water blockage condition in the formation.Two different alcohols were tested:isopropyl alcohol(IPA)and Methanol.Experimental results showed that mutual solvents significantly reduce water blockage and shorten the transition period.However,asphaltene precipitation may become a problem with increasing the molecular weight of injected alcohol.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41274111)the financial support of the National Department Public Benefit Research Foundation of MLR,China(Grant No.201211063-4-1)the One Hundred Talent Program of CAS(Grant No.O931061C01)
文摘Carbon dioxide(CO2) geosequestration in deep saline aquifers has been currently deemed as a preferable and practicable mitigation means for reducing anthropogenic greenhouse gases(GHGs) emissions to the atmosphere, as deep saline aquifers can offer the greatest potential from a capacity point of view. Hence,research on core-scale CO2/brine multiphase migration processes is of great significance for precisely estimating storage efficiency, ensuring storage security, and predicting the long-term effects of the sequestered CO2in subsurface saline aquifers. This review article initially presents a brief description of the essential aspects of CO2subsurface transport and geological trapping mechanisms, and then outlines the state-of-the-art laboratory core flooding experimental apparatus that has been adopted for simulating CO2injection and migration processes in the literature over the past decade. Finally, a summary of the characteristics, components and applications of publicly reported core flooding equipment as well as major research gaps and areas in need of further study are given in relevance to laboratory-scale core flooding experiments in CO2geosequestration under reservoir conditions.
文摘This paper introduces the results of selecting and breeding a micro-organism, Strain I, and its core model experiment investigation for microbial enhanced oil recovery (MEOR). Strain I was separated from the formation water of the Dagang oil field, with analytical results showing that Strain I is a gram-positive bacillus. A further study revealed that this strain has an excellent tolerance of environmental stresses: It can survive in conditions of 70℃, 30 wt% salinity and pH3.5-9.4. Strain I can metabolize biosurfactants that could increase the oil recovery ratio, use crude oil as the single carbon source, and decompose long-chain paraffin with a large molecular weight into short-chain paraffin with a small molecular weight. The core model experiment shows that Strain I enhances oil recovery well. Using 2 vol% of the fermentation solution of Strain I to displace the crude oil in the synthetic plastic bonding core could increase the recovery ratio by 21.6%.
基金Norhana Yahya for facilitating the research under the Alpha Matrix research group,UTP(Cost Centre:015LC0-149).
文摘A common assertion is that alkaline solution aids oil mobilization by generating in situ soap,or by lowering interfacial tension(IFT)to ultra-low values in synergy with surfactants.This study takes a different approach that involves the alkaline dissolution of detrital quartz grains of sandstone reservoirs to create pathways for oil migration and accumulation.Quartz dissolution via alkaline injection will result in changes in permeability and porosity.This study performed high-pH core flooding on Berea sandstones using core displacement equipment.Silica molybdate spectrophotometry was applied to measure the amount of dissolved silica.Inlet and confining pressure variations were also observed.The molar concentration of NaOH varied at 0.5 M and 1.0 M.The results show higher initial silica dissolution for 0.5 M NaOH(˃200mg/L)compared to 1.0 M NaOH(20 mg/L),which can be attributed to the presence of pre-existing dissolved silica and precipitates in the system prior to the first injection phase.Nonetheless,a steady quartz dissolution rate of 0.4 mg/L/hr for 20 h was only achieved at 1.0 M.Conversely,an abrupt drop in quartz dissolution to below 0 mg/L was recorded for 0.5 M NaOH after 3 h of dissolution.At higher molar concentration of injected alkaline solution,both confining and inlet pressures increased from 8 and 5 bars to 12 and 11 bars as a result of the increased secondary phase of(hydr)oxides or precipitates in the pores.Thus,it can be inferred that the effect of alkaline solution on quartz dissolution is strongly dependent on molar concentration.
基金funded by the National Natural Science Foundation of China (No. 52174046)。
文摘Despite advances in renewable energy sources, the world's current infrastructure and consumption patterns still heavily depend on crude oil. Enhanced oil recovery(EOR) is a crucial method for significantly increasing the amount of crude oil extracted from mature and declining oil fields. Nanomaterials have shown great potential in improving EOR methods due to their unique properties, such as high surface area, tunable surface chemistry, and the ability to interact at the molecular level with fluids and rock surfaces. This study examines the potential use of incorporating ethoxylated molybdenum disulfide with a unique three-dimensional flower-like morphology for overcoming the challenges associated with oil recovery from reservoirs characterized by complex pore structures and low permeability. The synthesized nanomaterial features a chemical composition that encompasses a polar ethoxy group linking molybdenum disulfide nanosheets and an alkylamine chain. The ethoxy group promotes interactions with water molecules through hydrogen bonding and electrostatic forces, disrupting the cohesive forces among water molecules and reduction surface tension at the oil-water interface. As a result, the nanomaterial achieves an ultra-low interfacial tension of 10^(-3) mN/m. Core flooding experiments demonstrate a significant oil recovery of approximately 70% at a concentration as low as 50 ppm. This research paves the way for the design and synthesis of advanced extended surfactant-like nanomaterials,offering a promising avenue for enhancing oil recovery efficiency.
基金the Ministry of Science and Innovation and State Research Agency for financial support throughout project PGC2018-097342-B-I00, including European Regional Development Fund。
文摘The main advantages of the use of ionic liquids in enhanced oil recovery are their tunability and stability in harsh environmental conditions. In this work, a comprehensive review of ionic liquids proposed to improve current chemical oil recovery methods has been presented, focusing on core flooding experiments. With an almost infinite number of possible ionic liquids, the amount of experiments carried out up to now has been very limited. However, results are promising, with additional recovery after secondary flooding of up to 32% of the original oil in place. Most formulations with ionic liquids have been proposed for sandstone reservoirs, the number of studies with carbonate cores being very scarce. The possibilities of a new room temperature surface active ionic liquid, 1-decyl-3-methylimidazolium triflate,for this application were analyzed. It was shown that it is able to drastically reduce the water/oil interfacial tension. An optimized formulation was proposed for carbonate reservoirs. After secondary flooding with brine, an additional recovery of 10.5% of original oil in place was achieved at room conditions. A combination of the proposed method followed by a polymer flooding step with polyacrylamide led to a lesser but still significant recovery, reducing the costs associated to the ionic liquid.
文摘To recover oil from brownfields,test air booster chemical flooding.Silica nanoparticle-polymer Arabic gum(SP)solution injection with controlled air injection is studied for displacement efficiency synergy.Multiple crude oil-soaked core samples were employed in lab core flooding procedures to approximate reservoir conditions.Performance depended on pressure drop,burst duration,and oil recovery.Study:continuous oxygen air flooding eliminates less oil from the ground than AAW.Results from experiments supported this.Air alternative water(AAW)optimises oil recovery and efficiency by regulating flow.In congested reservoirs,air can replace water.Constant air sealing keeps oil from water.Air alternative water(AAW)systems use polymers like Arabic gum,silica nanoparticles,and a mix of the two to remove oil and prevent water contamination.Nano-polymer-alternating-water(NPAW)creates air alternate water(AAW).Three-phase flow with silica and Arabic gum is studied in this study.A two-phase investigation used combination,silica,and polymer/oil.Water/oil and combination/oil displacement boosted oil output and relative permeability,unlike polymer/oil and nanoparticles.Air and oil have lower surface resistance than water.Air injection sweeps outperform water floods technically.Lab scientists analyse chemical fluid-oil interfacial tension with polymer-silica and NaCl.Air,fluid,and fluid injections recovered 48.6%,20%,and 16.7%of oil in core flooding testing.This reveals that air,Arabic gum,and silica nanoparticles greatly improve lab core oil recovery.The air boosters increased oil flow,residual saturation,and sweep.Chemicals and air injection improve older deposit EOR.
文摘Different methods of enhanced oil recovery have been used to produce trapped oil.One of these methods is carbonated water injection in which CO2 contained water is injected in reservoirs in order to decrease free CO2 injection mobility,increase water viscosity and store/remove produced greenhouse CO2 gas safely.Another enhanced oil recovery method is smart water injection at which the ions in brine are modified in order to make controlled reactions with distributed ions on the surface of rock to cause more hydrocarbon recovery.Therefore,combination of these two methods may also have a great effect on enhancing oil recovery or may result in recovery factor less than each method used alone.In this paper hybrid smart carbonated water injection method is investigated to study its applicability in oil recovery using core flooding setup.The experimental core flooding setup was designed to perform different types of EOR methods for the sake of recovery comparison with the new hybrid method.The effect of both brine content and volume of CO2 is determining in hybrid EOR assessment.The main findings of this work show that the hybrid smart carbonated water results in the highest recovery factor in comparison to the most well-known EOR methods for carbonate cores.
基金Nazarbayev University for supporting this research through the NU Faculty Development Competitive Research Grants Program(Grant numbers:20122022FD4137(AHA)).
文摘Advancing the use of natural surfactants in enhanced oil recovery is crucial for sustainable practices in the oil and gas industry.This research assesses the applicability of neem-derived natural surfactants in offshore fields,encompassing surfactant synthesis via saponification,characterization through FT-IR,SEM,and EDS,and measuring surface and interfacial tension across various conditions.Adsorption studies determined the surfactant's adsorption characteristics onto rock,and core flooding tests assessed its efficacy.Surface tension measurements in deionized water(DIW)and brine confirmed the surfactant's surface activity.As the concentration increased from 1 wt%to 6 wt%,the interfacial tension(IFT)significantly decreased from 22.5 mN/m to 7.9 mN/m,marking a 64.8%reduction.Additionally,surfactants formed micelles more efficiently in saline water,with the critical micelle concentration(CMC)dropping from 4.0 wt%in DIW to 0.9 wt%.Adsorption on limestone showed over 50%higher adsorption than sandstone,confirming stronger interactions and higher adsorption saturation.Core flooding experiments demonstrated the surfactant's effectiveness in oil and water-wet conditions.When injected into sandstone,the surfactant achieved a significant additional oil recovery of 24.6%in deionized water,compared to 10.2%in limestone.Conversely,in saline conditions,the surfactant's performance was better in limestone,achieving an additional recovery of 4.9%,whereas in sandstone,it was only 1.6%.This research offers a unique perspective on how natural surfactants perform across different rock types.The findings suggest that neem-derived surfactants hold significant promise for enhancing oil recovery in Kazakhstan's oil fields.
文摘Enhanced oil recovery(EOR)methods are essential for optimizing oil extraction from modern reservoirs.This research delved into the synergistic impact of combining anionic and nonionic surfactant mixtures with silica(SiO_(2))nanoparticles(NPs)in sodium chloride(NaCl)solutions,alongside the added enhancement of polymers,to improve crude oil recovery.The study comprehensively evaluated stability,rheological characteristics,interfacial tension(IFT)behavior,wettability alterations,and EOR experi ments using mixtures of sodium dodecyl sulfate(SDS)and triton X-100(TX-100)surfactants.Scenarios both with and without SiO_(2)NPs in a base solution containing 3000 ppm NaCl and 2000 ppm xanthan gum(XG)polymer were examined.Core flooding tests were carried out on San-Saba sandstone core specimens with low permeability.The stability tests and dynamic light scattering(DLS)analysis were performed to assess the stability of NPs in low saline-surfactant-polymer solution.It was observed that NPs significantly reduced the IFT between the test solutions and crude oil,with nanofluids exhibiting satisfactory stability at a 0.4 wt%SiO_(2)NPs concentration.Core flooding studies demonstrated a syner gistic interaction between NPs and the binary surfactant-polymer mixture,resulting in substantially greater incremental recovery of oil in comparison with the case of using binary surfactant-polymer combination alone.The mechanisms contributing to EOR with nanofluids,such as IFT reduction and wettability alteration,were explored.Incorporating NPs at concentrations of 0.1,0.2,and 0.4 wt%led to incremental oil recoveries of 4.01%,12.35%,and 12.73%of the original oil in place(OOIP),respectively,as opposed to the recovery achieved using only SDS+TX-100+XG.Consequently,these findings advance the understanding of the potential application of SiO_(2)NPs in combination with the binary surfactant polymer mixture as effective chemical EOR agents.Additionally,these insights aid in identifying suit able sandstone reservoirs for nanofluid application,contributing to the optimization of oil recovery strategies.
文摘This research examines the impact of wettability alteration on the end points of relative permeability,a crucial property of fluids and porous media that influences the displacement processes of immiscible fluids through such media.The estimation of the mobility ratio for oil recovery relies on these end points,which are influenced by connate water saturation and residual oil saturation.To investigate this relationship,carbonate rock is generally subjected to wettability alteration using surfactant agents,and core flooding is employed to determine the relative permeability before and after the alteration.The wettability of the rock is commonly assessed through contact angle measurements.Two surfactants,TritonX-100(Tx-100)and Cedar,were tested in reducing the wettability of the porous media for oil.The contact angle measurements revealed that Tx-100 was more effective for this purpose than Cedar.Furthermore,the relative permeability tests indicated that both surfactants decreased residual oil saturation,but Tx-100 also improved system pressure.In contrast,Cedar reduced residual oil saturation but increased system pressure,possibly because of its high viscosity.The results also demonstrate that injecting Tx-100 leads to a 14%increase in ultimate oil recovery compared with water injection,while Cedar injection increased the recovery factor by 5%.This difference may be attributed to the incomplete coverage of the pore wall by Cedar or its weaker chemical structure than Tx-100.Notably,in carbonate cores,neither non-ionic surfactant enhanced oil recovery.
文摘Matrix acidizing is usually conducted on sandstone reservoirs to increase hydrocarbon production.Mineralogy plays an important role in designing acidizing treatments to enhance the production of oil and gas from sandstone reservoirs.The most common acid in practice to acidize sandstone formation is mud acid after the pre-flush acid stage.The main aim of the pre-flush acid stage is to dissolve positive ions like calcium,potassium,sodium,etc,which can cause precipitation reactions during the mud acid stage.This research is aimed to investigate the reaction mechanism of a new pre-flush acid combination(hydrochloric acid and acetic acid)with sandstone formation.Core flooding experiments were performed to react acid with the core samples(6 in×1.5 in)under high pressure and temperature(HPHT)condi-tions(80℃and 1000 psia).Analytical techniques such as Tescan Integrated Mineral Analysis(TIMA)have been used to illustrate the effect of these acids on sandstone formation.TIMA analysis showed that the new acid combination was effective in dissolving various minerals(ankerite,magnetite)and cations(calcium,magnesium,sodium,and iron).15%HCl proved to be more effective in the dissolution of different particles from sandstone core samples.It dissolved 32.8%of the initial number of particles present inside the sample while the dissolving power of 5%CH_(3)COOH:10%HCl is 26.7%.Subsequently,the number of pores increased by the application of 15%HCl is 22%while that by 5%CH_(3)COOH:10%HCl is 21.8%.Density analysis showed that both acid combinations removed heavy particles effectively,whereas 5%CH_(3)COOH:10%HCl proved more efficient in dissolving calcium ions which is very important for pre-flush acidizing.
文摘This study explores the effectiveness of alcohol injection as a stimulation treatment to mitigate water blockage in the vicinity of the wellbore.Over the years,water blockage has emerged as a recurring challenge within the oil and gas industry,leading to diminished well productivity.In a commingled reservoir with multiple layers,when a producing well is shut-in for well intervention or workover,water may encroach from water zones into the oil-bearing formations through the wellbore due to pressure differences between the layers.Water encroachment can have a significant impact on the production of a well.It can reduce the oil production rate,increase the water cut,and shorten the well's lifespan.Therefore,it is essential to take steps to mitigate the water encroachment effect in commingled reser-voirs.This study explores the use of alcohol injection to reduce transition time and remediate formation damage in commingled oil reservoirs.Limited studies have shown that alcohol has the potential to enhance fluid relative Permeability in gas condensate reservoirs and reduce condensate banking near the wellbore.However,this approach has not yet been tested in commingled oil reservoirs.A series of core flooding tests were conducted using Berea sandstone cores and a Texan light crude oil sample.The core flood setup was designed to represent the water blockage condition in the formation.Two different alcohols were tested:isopropyl alcohol(IPA)and Methanol.Experimental results showed that mutual solvents significantly reduce water blockage and shorten the transition period.However,asphaltene precipitation may become a problem with increasing the molecular weight of injected alcohol.
