Hydraulic fracturing is widely accepted and applied to improve the gas recovery in unconventional reservoirs.Unconventional reservoirs to be addressed here are with very low permeability,complicated geological setting...Hydraulic fracturing is widely accepted and applied to improve the gas recovery in unconventional reservoirs.Unconventional reservoirs to be addressed here are with very low permeability,complicated geological settings and in-situ stress field etc.All of these make the hydraulic fracturing process a challenging task.In order to effectively and economically recover gas from such reservoirs,the initiation and propagation of hydraulic fracturing in the heterogeneous fractured/porous media under such complicated conditions should be mastered.In this paper,some issues related to hydraulic fracturing have been reviewed,including the experimental study,field study and numerical simulation.Finally the existing problems that need to be solved on the subject of hydraulic fracturing have been proposed.展开更多
Carbon dioxide capture,utilization and storage(CCUS)eincluding conversion to valuable chemicals-is a challenging contemporary issue having multi-facets.The prospect to utilize carbon dioxide(CO_(2))as a feedstock for ...Carbon dioxide capture,utilization and storage(CCUS)eincluding conversion to valuable chemicals-is a challenging contemporary issue having multi-facets.The prospect to utilize carbon dioxide(CO_(2))as a feedstock for synthetic applications in chemical and fuel industries-through carboxylation and reduction reactions-is the subject of this review.Current statute of the heterogeneously catalyzed hydrogenation,as well as the photocatalytic and electrocatalytic activations of conversion of CO_(2) to value-added chemicals is overviewed.Envisaging CO_(2) as a viable alternative to natural gas and oil as carbon resource for the chemical supply chain,three stages of development;namely,(i)existing mature technologies(such as urea production),(ii)emerging technologies(such as formic acid or other single carbon(C1)chemicals manufacture)and(iii)innovative explorations(such as electrocatalytic ethylene production)have been identified and highlighted.A unique aspect of this review is the exploitations of reactions of CO2 ewhich stems from existing petrochemical plants-with the commodity petrochemicals(such as,methanol,ethylene and ethylene oxide)produced at the same or nearby complex in order to obtain value-added products while contributing also to CO_(2) fixation simultaneously.Exemplifying worldwide ethylene oxide facilities,it is recognized that they produce about 3 million tons of CO2 annually.Such a CO_(2) resource,which is already separated in pure form as a requirement of the process,should best be converted to a value-added chemical there avoiding current practice of discharging to the atmosphere.The potential utilization of CO_(2),captured at power plants,should also been taken into consideration for sustainability.This CO_(2) source,which is potentially a raw material for the chemical industry,will be available at sufficient quality and at gigantic quantity upon realization of on-going tangible capture projects.Products resulting from carboxylation reactions are obvious conversions.In addition,provided that enough s展开更多
The main function of traditional proppants is to provide and maintain conductive fractures during well production where proppants should meet closure stress requirement and show resistance to diagenesis under downhole...The main function of traditional proppants is to provide and maintain conductive fractures during well production where proppants should meet closure stress requirement and show resistance to diagenesis under downhole conditions.Many different proppants have been developed in the oil&gas industry,with various types,sizes,shapes,and applications.While most proppants are simply made of silica or ceramics,advanced proppants like ultra-lightweight proppant is also desirable since it reduces proppant settling and requires low viscosity fluids to transport.Additionally,multifunctional proppants may be used as a crude way to detect hydraulic fracture geometry or as matrices to slowly release downhole chemical additives,besides their basic function of maintaining conductive hydraulic fractures.Different from the conventional approach where proppant is pumped downhole in frac fluids,a revolutionary way to generate in-situ spherical proppants has been reported recently.This paper presents a comprehensive review of over 100 papers published in the past several decades on the subject.The objectives of this review study are to provide an overview of current proppant technologies,including different types,compositions,and shapes of proppants,new technologies to pump and organize proppants downhole such as channel fracturing,and also in-situ proppant generation.Finally,the paper sheds light on the current challenges and emphasizes needs for new proppant development for unconventional resources.展开更多
Chemical enhanced oil recovery(EOR)and particularly surfactant injection has recently received a great deal of attention.The suggested recovery mechanisms after injecting surfactants include wettability alteration and...Chemical enhanced oil recovery(EOR)and particularly surfactant injection has recently received a great deal of attention.The suggested recovery mechanisms after injecting surfactants include wettability alteration and IFT reduction.If a surfactant is properly selected according to the environmental variables-such as pressure,temperature,salinity,it can lead to more efficient enhanced recovery from an oil reservoir.On the other hand,poor selection of the surfactant can result in a low recovery and can even become detrimental to the reservoir due to undesirable wettability alteration and possible rock dissolution resulting in a chemical reaction with displacing fluid and blockage of the pore space.Also,choosing the wrong surfactant without considering the rock mineralogy may result in high adsorption on the pore surface of the rock and unnecessary waste of resources.It is also worthy to note that surfactants are some of the most expensive chemicals used during EOR.Extensive literature review suggests that anionic surfactant are the preferred surfactant category for EOR especially when it comes to sandstone reservoirs.Occasionally,in specific situations a better performance have been reported after injecting cationic,non-ionic or mixtures of both surfactants,particularly when dealing with carbonate reservoirs.This paper presents in detail a review of the most commonly applied surfactants in EOR studies and the optimum application criteria for of each type.To the best of the authors'knowledge,such detailed and comprehensive review is not available in the literature,presently.展开更多
Surfactant enhanced oil recovery(EOR)includes surfactant flooding and surfactant stimulation.The main functions of surfactants are to reduce interfacial tension and wettability alteration.This paper is to review the E...Surfactant enhanced oil recovery(EOR)includes surfactant flooding and surfactant stimulation.The main functions of surfactants are to reduce interfacial tension and wettability alteration.This paper is to review the EOR technology related to surfactant injection.The reviewed topics include the following:Surfactant EOR mechanismsFactors affecting interfacial tension Trapping numberScreening criteriaLaboratory work Numerical simulation work Summary of pilot and large-scale applications Surfactants used Salinity gradientSurfactant EOR in carbonate reservoirs Surfactant EOR in shale reservoirs.展开更多
As a serious problem in drilling operation,wellbore instability restricts efficient development of shale gas.The interaction between the drilling fluid and shale with hydration swelling property would have impact on t...As a serious problem in drilling operation,wellbore instability restricts efficient development of shale gas.The interaction between the drilling fluid and shale with hydration swelling property would have impact on the generation and propagation mechanism of cracks in shale formation,leading to wellbore instability.In order to investigate the influence of the hydration swelling on the crack propagation,mineral components and physicochemical properties of shale from the Lower Silurian Longmaxi Formation(LF)were investigated by using the XRD analysis,cation exchange capabilities(CEC)analysis,and SEM observation,and we researched the hydration mechanism of LF shale.Results show that quartz and clay mineral are dominated in mineral composition,and illite content averaged 67%in clay mineral.Meanwhile,CEC of the LF shale are 94.4 mmol/kg.The process of water intruding inside shale along microcracks was able to be observed through high power microscope,meanwhile,the hydration swelling stress would concentrate at the crack tip.The microcracks would propagate,bifurcate and connect with each other,with increase of water immersing time,and it would ultimately develop into macro-fracture.Moreover,the macrocracks extend and coalesce along the bedding,resulting in the rock failure into blocks.Hydration swelling is one of the major causes that lead to wellbore instability of the LF shale,and therefore improving sealing capacity and inhibition of drilling fluid system is an effective measure to stabilize a borehole.展开更多
The energy resources mainly petroleum and petroleum hydrocarbons are major pollutants of the environment.The oil and oil products contamination may cause severe harm and hence,the attention has been remunerated in the...The energy resources mainly petroleum and petroleum hydrocarbons are major pollutants of the environment.The oil and oil products contamination may cause severe harm and hence,the attention has been remunerated in the development of alternative technologies for elimination of these contaminants.Biosurfactants were used in the remediation of oil pollution due to advantages such as biodegradability and low toxicity.The biosurfactants are produced from low cost substrates like agro-industrial wastes which reduce the cost of production.Biosurfactants and bioemulsifiers are amphiphilic compounds and are produced as extracellular or a part of the cell membrane by bacteria.The insight view,how hydrocarbons are degraded by microorganisms and thereby reduce the damage of ecosystem is highly essential to target the problem.Biofilms are the bacterial communities which protects the bacterial cells from various adverse conditions.The present review describes the biosurfactants and its synthesis from bacteria and also emphases on the role of surfactants in oil remediation.展开更多
This paper deals with the comparison of models for predicting porosity and permeability of oil reservoirs by coupling a machine learning concept and petrophysical logs.Different machine learning methods including conv...This paper deals with the comparison of models for predicting porosity and permeability of oil reservoirs by coupling a machine learning concept and petrophysical logs.Different machine learning methods including conventional artificial neural network,genetic algorithm,fuzzy decision tree,the imperialist competitive algorithm(ICA),particle swarm optimization(PSO),and a hybrid of those ones are employed to have a comprehensive comparison.The machine learning approach was constructed and tested via data samples recorded from northern Persian Gulf oil reservoirs.The results gained from the machine learning models used in this paper are compared to the relevant real petrophysical data and the outputs achieved by other methods employed in our previous studies.The average relative absolute deviation between the approach estimations and the relevant actual data is found to be less than 1%for the hybridized approaches.The results reported in this paper indicate that implication of hybridized machine learning methods in porosity and permeability estimations can lead to the construction of more reliable static reservoir models in simulation plans.展开更多
The application of distributed temperature sensors(DTS)to monitor producing zones of horizontal well through a real-time measurement of a temperature profile is becoming increasingly popular.Those parameters,such as f...The application of distributed temperature sensors(DTS)to monitor producing zones of horizontal well through a real-time measurement of a temperature profile is becoming increasingly popular.Those parameters,such as flow rate along wellbore,well completion method,skin factor,are potentially related to the information from DTS.Based on mass-,momentum-,and energy-balance equations,this paper established a coupled model to study on temperature distribution along wellbore of fracturing horizontal wells by considering skin factor in order to predict wellbore temperature distribution and analyze the factors influencing the wellbore temperature profile.The models presented in this paper account for heat convective,fluid expansion,heat conduction,and viscous dissipative heating.Arriving temperature and wellbore temperature curves are plotted by computer iterative calculation.The non-perforated and perforated sections show different temperature distribution along wellbore.Through the study on the sensitivity analysis of skin factor and flow rate,we come to the conclusion that the higher skin factor generates larger temperature increase near the wellbore,besides,temperature along wellbore is related to both skin factors and flow rate.Temperature response type curves show that the larger skin factor we set,the less temperature augmenter from toe to heel could be.In addition,larger flow rate may generate higher wellbore temperature.展开更多
The development of shale reservoirs has brought a paradigm shift in the worldwide energy equation.This entails developing robust techniques to properly evaluate and unlock the potential of those reservoirs.The applica...The development of shale reservoirs has brought a paradigm shift in the worldwide energy equation.This entails developing robust techniques to properly evaluate and unlock the potential of those reservoirs.The application of Nuclear Magnetic Resonance techniques in fluid typing and properties estimation is well-developed in conventional reservoirs.However,Shale reservoirs characteristics like pore size,organic matter,clay content,wettability,adsorption,and mineralogy would limit the applicability of the used interpretation methods and correlation.Some of these limitations include the inapplicability of the controlling equations that were derived assuming fast relaxation regime,the overlap of different fluids peaks and the lack of robust correlation to estimate fluid properties in shale.This study presents a state-of-the-art review of the main contributions presented on fluid typing methods and correlations in both experimental and theoretical side.The study involves Dual Tw,Dual Te,and doping agent's application,T1-T2,D-T2 and T2sec vs.T1/T2 methods.In addition,fluid properties estimation such as density,viscosity and the gas-oil ratio is discussed.This study investigates the applicability of these methods along with a study of the current fluid properties correlations and their limitations.Moreover,it recommends the appropriate method and correlation which are capable of tackling shale heterogeneity.展开更多
Nanotechnology has attracted a great attention in enhancing oil recovery(EOR)due to the costeffective and environmental friendly manner.The size of nanoparticles for EOR usually is in a range of 1e100 nm,which may sli...Nanotechnology has attracted a great attention in enhancing oil recovery(EOR)due to the costeffective and environmental friendly manner.The size of nanoparticles for EOR usually is in a range of 1e100 nm,which may slightly differ from various international organisations.Nanoparticles exhibit significantly different properties compared to the same fine or bulk molecules because of much higher concentration of atoms at their surface as a result of ultra-small size.In particular,one of the most useful and fascinating properties of these particles is to creating a massive diffusion driving force due to the large surface area,especially at high temperatures.Previous studies have shown that nanoparticles can enhance oil recovery by shifting reservoir wettability towards more water-wet and reducing interfacial tension,yet this area is still open for discussion.It is worth noting that the potential of nanoparticles to reduce the oil viscosity,increase the mobility ratio,and to alter the reservoir permeability has not been investigated to date.Depending on the operational conditions of the EOR process,some nanoparticles perform more effectively than others,thus leading to different levels of enhanced recovery.In this study,we aim to provide a summary on each of the popular and available nanoparticles in the market and list their optimum operational conditions.We classified nanoparticles into the three categories of metal oxide,organic and inorganic particles in this article.展开更多
The EOR techniques are employed to recover more oil from mature reservoirs after the primary and secondary oil production stages.Polymer flooding as a chemical EOR method involves adding polymer molecules in order to ...The EOR techniques are employed to recover more oil from mature reservoirs after the primary and secondary oil production stages.Polymer flooding as a chemical EOR method involves adding polymer molecules in order to increase water viscosity.Increasing water viscosity will improve the mobility ratio of injected fluid to reservoir fluid toward a more favorable value.Therefore,vertical and areal sweep efficiencies are increased compared to typical water flooding.Polymer flooding will be most effective if applied in the early stages of a water flood while the mobile oil saturation is still high.Polymer is also a critical component when considering other chemical EOR technologies such as alkaline-polymer or alkaline-surfactant-polymer.The present study covers two main parts.In the first part,fundamental of polymer flooding as it related to experimental work and simulation are discussed.The challenge of polymer flooding applications in high temperature and high salinity(HTHS)environment is also discussed in this part.In the second part,the synergy of polymer with surfactant and alkaline as chemical enhancing oil recovery(CEOR)methods is discussed.展开更多
The application of nanotechnology in the oil and gas industry is on the rise as evidenced by the number of researches undertaken in the past few years.The quest to develop more game-changing technologies that can addr...The application of nanotechnology in the oil and gas industry is on the rise as evidenced by the number of researches undertaken in the past few years.The quest to develop more game-changing technologies that can address the challenges currently facing the industry has spurred this growth.Several nanoparticles,of different sizes and at different concentrations,have been used in many investigations.In this work,the scope of the study covered the application of nanotechnology in drilling and hydraulic fracturing fluids,oilwell cementing,enhanced oil recovery(which includes transport study,and foam and emulsion stability),corrosion inhibition,logging operations,formation fines control during production,heavy oil viscosity reduction,hydrocarbon detection,methane release from gas hydrates,and drag reduction in porous media.The observed challenges associated with the use of nanoparticles are their stability in a liquid medium and transportability in reservoir rocks.The addition of viscosifier was implemented by researchers to ensure stability,and also,surface-treated nanoparticles have been used to facilitate stability and transportability.For the purpose of achieving better performance or new application,studies on synergistic effects are suggested for investigation in future nanotechnology research.The resulting technology from the synergistic studies may reinforce the current and future nanotechnology applications in the oil and gas industry,especially for high pressure and high temperature(HPHT)applications.To date,majority of the oil and gas industry nanotechnology publications are reports of laboratory experimental work;therefore,more field trials are recommended for further advancement of nanotechnology in this industry.Usually,nanoparticles are expensive;so,it will be cost beneficial to use the lowest nanoparticles concentration possible while still achieving an acceptable level of a desired performance.Hence,optimization studies are also recommended for examination in future nanotechnology research.展开更多
This paper reviews the utilization of Big Data analytics,as an emerging trend,in the upstream and downstream oil and gas industry.Big Data or Big Data analytics refers to a new technology which can be employed to hand...This paper reviews the utilization of Big Data analytics,as an emerging trend,in the upstream and downstream oil and gas industry.Big Data or Big Data analytics refers to a new technology which can be employed to handle large datasets which include six main characteristics of volume,variety,velocity,veracity,value,and complexity.With the recent advent of data recording sensors in exploration,drilling,and production operations,oil and gas industry has become a massive data intensive industry.Analyzing seismic and micro-seismic data,improving reservoir characterization and simulation,reducing drilling time and increasing drilling safety,optimization of the performance of production pumps,improved petrochemical asset management,improved shipping and transportation,and improved occupational safety are among some of the applications of Big Data in oil and gas industry.Although the oil and gas industry has become more interested in utilizing Big Data analytics recently,but,there are still challenges mainly due to lack of business support and awareness about the Big Data within the industry.Furthermore,quality of the data and understanding the complexity of the problem are also among the challenging parameters facing the application of Big Data.展开更多
Cusp displacement catastrophe theory can be introduced to propose a new method about instability failure of the interbed for gas storage cavern in bedded salt in solution mining.We can calculate initial fracture drawi...Cusp displacement catastrophe theory can be introduced to propose a new method about instability failure of the interbed for gas storage cavern in bedded salt in solution mining.We can calculate initial fracture drawing pace of this interbed to obtain 2D and 3D gas storage shapes at this time.Moreover,Stability evaluation of strength reduction finite element method(FEM)based on this catastrophe theory can used to evaluate this interbed stability after initial fracture.A specific example is simulated to obtain the influence of the interbed depth,cavern internal pressure,and cavern building time on stability safety factor(SSF).The results indicate:the value of SSF will be lower with the increase of cavern building time in solution mining and the increase of interbed depth and also this value remains a rise with the increase of cavern internal pressure Especially,we can conclude that the second-fracture of the interbed may take place when this pressure is lower than 6 MPa or after 6 days later of the interbed after initial fracture.According to above analysis,some effective measures,namely elevating the tube up to the top of the interbed,or changing the circulation of in-and-out lines,can be introduced to avoid the negative effects when the secondfracture of the interbed may occur.展开更多
Greater complexity is involved in the transient pressure analysis of horizontal oil wells in contrast to vertical wells,as the horizontal wells are considered entirely horizontal and parallel with the top and undernea...Greater complexity is involved in the transient pressure analysis of horizontal oil wells in contrast to vertical wells,as the horizontal wells are considered entirely horizontal and parallel with the top and underneath boundaries of the oil reserve.Therefore,there is an essential need to estimate productivity of horizontal wells accurately to examine the effectiveness of a horizontal well in terms of technical and economic prospects.In this work,novel and rigorous methods based on two different types of intelligent approaches including the artificial neural network(ANN)linked to the particle swarm optimization(PSO)tool are developed to precisely forecast the productivity of horizontal wells under pseudo-steady-state conditions.It was found that there is very good match between the modeling output and the real data taken from the literature,so that a very low average absolute error percentage is attained(e.g.,<0.82%).The developed techniques can be also incorporated in the numerical reservoir simulation packages for the purpose of accuracy improvement as well as better parametric sensitivity analysis.展开更多
Amines are well-known for their reversible reactions with CO_(2),which make them ideal for CO_(2) capture from several gas streams,including flue gas.In this respect,selective CO_(2) absorption by aqueous alkanolamine...Amines are well-known for their reversible reactions with CO_(2),which make them ideal for CO_(2) capture from several gas streams,including flue gas.In this respect,selective CO_(2) absorption by aqueous alkanolamines is the most mature technology but the process is energy intensive and has also corrosion problems.Both disadvantages can be diminished to a certain extent by chemical adsorption of CO_(2) selectively.The most important element of the chemical adsorption of CO_(2) involves the design and development of a suitable adsorbent which consist of a porous support onto which an amine is attached or immobilized.Such an adsorbent is often called as solid amine sorbent.This review covers solid amine-based studies which are developed and published in recent years.First,the review examines several different types of porous support materials,namely,three mesoporous silica(MCM-41,SBA-15 and KIT-6)and two polymeric supports(PMMA and PS)for CO_(2) adsorption.Emphasis is given to the synthesis,modifications and characterizations-such as BET and PXRD data-of them.Amination of these supports to obtain a solid amine sorbent through impregnation or grafting is reviewed comparatively.Focus is given to the adsorption mechanisms,material characteristics,and synthesis methods which are discussed in detail.Significant amount of original data are also presented which makes this review unique.Finally,relevant CO_(2) adsorption(or equilibrium)capacity data,and cyclic adsorption/desorption performance and stability of important classes of solid amine sorbents are critically reviewed.These include severa PEI or TEPA impregnated adsorbents and APTES-grafted systems.展开更多
In recent years,controlling the salinity and composition of the injected water has become an emerging enhanced oil recovery(EOR)technique,often described as low salinity(LS)waterflooding.This work is done with the int...In recent years,controlling the salinity and composition of the injected water has become an emerging enhanced oil recovery(EOR)technique,often described as low salinity(LS)waterflooding.This work is done with the intention to contribute to the ongoing discussions about LS waterflooding mechanism(s).For this purpose,a series of different experiments were conducted.At first,the effect of salinity on the interfacial tension(IFT)and the contact angle was evaluated with a crude oil sample.Then to achieve more accurate results in observing oil/water interface,similar IFT experiments were also carried out on a synthetic oil containing asphaltenes.Thereafter,microscopic visualization using glass micromodel was performed on the interface of the synthetic oil sample and brines.Four brine solutions including Sea Water(SW),it's dilutions and formation water(FW)were used for various experiments.Finally,to investigate the presented mechanism by other authors,a series of Environmental Scanning Electron Microscopy(ESEM)analysis on the synthetic oil was carried out to understand better the phase behaviour after contacting both synthetic oil and water phases from the micromodel experiment.Based on the existing mechanism,there exists an optimal concentration beyond which dilution is no longer an effective process.展开更多
Due to the high viscosity of heavy crude oils,production from these reservoirs is a demanding task.To tackle this problem,reducing oil viscosity is a promising approach.There are various methods to reduce viscosity of...Due to the high viscosity of heavy crude oils,production from these reservoirs is a demanding task.To tackle this problem,reducing oil viscosity is a promising approach.There are various methods to reduce viscosity of heavy oil:heating,diluting,emulsification,and core annular flow.In this study,dilution approach was employed,using industrial solvents and gas condensate.The viscosity of two Iranian heavy crude oils was measured by mixing with solvents at different temperatures.Dilution of both oil samples with toluene and heptane,resulted in viscosity reduction.However,their effect became less significant at higher concentrations of diluent.Because of forming hydrogen bonds,adding methanol to heavy crude oil resulted in higher viscosity.By adding condensate,viscosity of each sample reduced.Gas condensate had a greater impact on heavier oil;however,at higher temperatures its effect was reduced.Diluting with naphtha decreased heavy oil viscosity in the same way as n-heptane and toluene.Besides experimental investigation,different viscosity models were evaluated for prediction of heavy oil/solvent viscosity.It was recognized that Lederer'model is the best one.展开更多
Nanoparticles have been widely used to reduce wellbore instability problems of shale formation.In this paper,nanoparticle-containing water-based drilling fluids(WBDFs)and oil-based drilling fluids(OBDFs)were evaluated...Nanoparticles have been widely used to reduce wellbore instability problems of shale formation.In this paper,nanoparticle-containing water-based drilling fluids(WBDFs)and oil-based drilling fluids(OBDFs)were evaluated by running three new tests including spontaneous imbibition,swelling rate and acoustic transit time.Results showed that,for the WBDFs,nanoparticles leaded to higher plastic viscosity(PV)and yield point(YP),and lower API-filtration.Moreover,because pore throats of shale can be plugged by nanoparticles,imbibition amount,swelling rate,and Young's-modulus reduction of shale decreased significantly.Higher concentration of nanoparticles can induce better plugging effect.However,for the OBDFs,nanoparticles did not show these positive effects like the nano WBDFs,even leaded to some negative effects such as higher filtration and larger Young'smodulus reduction.The main reasons are that the silica nanoparticles can easily disperse in the WBDFs,and effectively prevent the filtrate invading into shale by plugging pore throats.But the same silica nanoparticles are difficult to disperse in OBDFs,and do not perform the expected functions.This study indicates that nano WBDFs have great potential to reduce the wellbore instability problems of shale formation.展开更多
文摘Hydraulic fracturing is widely accepted and applied to improve the gas recovery in unconventional reservoirs.Unconventional reservoirs to be addressed here are with very low permeability,complicated geological settings and in-situ stress field etc.All of these make the hydraulic fracturing process a challenging task.In order to effectively and economically recover gas from such reservoirs,the initiation and propagation of hydraulic fracturing in the heterogeneous fractured/porous media under such complicated conditions should be mastered.In this paper,some issues related to hydraulic fracturing have been reviewed,including the experimental study,field study and numerical simulation.Finally the existing problems that need to be solved on the subject of hydraulic fracturing have been proposed.
基金Authors gratefully acknowledge Hasan Arslan,Senior Process Consultant,PTTGC America,for the hindsight provided for matured and developing petrochemical processes.
文摘Carbon dioxide capture,utilization and storage(CCUS)eincluding conversion to valuable chemicals-is a challenging contemporary issue having multi-facets.The prospect to utilize carbon dioxide(CO_(2))as a feedstock for synthetic applications in chemical and fuel industries-through carboxylation and reduction reactions-is the subject of this review.Current statute of the heterogeneously catalyzed hydrogenation,as well as the photocatalytic and electrocatalytic activations of conversion of CO_(2) to value-added chemicals is overviewed.Envisaging CO_(2) as a viable alternative to natural gas and oil as carbon resource for the chemical supply chain,three stages of development;namely,(i)existing mature technologies(such as urea production),(ii)emerging technologies(such as formic acid or other single carbon(C1)chemicals manufacture)and(iii)innovative explorations(such as electrocatalytic ethylene production)have been identified and highlighted.A unique aspect of this review is the exploitations of reactions of CO2 ewhich stems from existing petrochemical plants-with the commodity petrochemicals(such as,methanol,ethylene and ethylene oxide)produced at the same or nearby complex in order to obtain value-added products while contributing also to CO_(2) fixation simultaneously.Exemplifying worldwide ethylene oxide facilities,it is recognized that they produce about 3 million tons of CO2 annually.Such a CO_(2) resource,which is already separated in pure form as a requirement of the process,should best be converted to a value-added chemical there avoiding current practice of discharging to the atmosphere.The potential utilization of CO_(2),captured at power plants,should also been taken into consideration for sustainability.This CO_(2) source,which is potentially a raw material for the chemical industry,will be available at sufficient quality and at gigantic quantity upon realization of on-going tangible capture projects.Products resulting from carboxylation reactions are obvious conversions.In addition,provided that enough s
文摘The main function of traditional proppants is to provide and maintain conductive fractures during well production where proppants should meet closure stress requirement and show resistance to diagenesis under downhole conditions.Many different proppants have been developed in the oil&gas industry,with various types,sizes,shapes,and applications.While most proppants are simply made of silica or ceramics,advanced proppants like ultra-lightweight proppant is also desirable since it reduces proppant settling and requires low viscosity fluids to transport.Additionally,multifunctional proppants may be used as a crude way to detect hydraulic fracture geometry or as matrices to slowly release downhole chemical additives,besides their basic function of maintaining conductive hydraulic fractures.Different from the conventional approach where proppant is pumped downhole in frac fluids,a revolutionary way to generate in-situ spherical proppants has been reported recently.This paper presents a comprehensive review of over 100 papers published in the past several decades on the subject.The objectives of this review study are to provide an overview of current proppant technologies,including different types,compositions,and shapes of proppants,new technologies to pump and organize proppants downhole such as channel fracturing,and also in-situ proppant generation.Finally,the paper sheds light on the current challenges and emphasizes needs for new proppant development for unconventional resources.
文摘Chemical enhanced oil recovery(EOR)and particularly surfactant injection has recently received a great deal of attention.The suggested recovery mechanisms after injecting surfactants include wettability alteration and IFT reduction.If a surfactant is properly selected according to the environmental variables-such as pressure,temperature,salinity,it can lead to more efficient enhanced recovery from an oil reservoir.On the other hand,poor selection of the surfactant can result in a low recovery and can even become detrimental to the reservoir due to undesirable wettability alteration and possible rock dissolution resulting in a chemical reaction with displacing fluid and blockage of the pore space.Also,choosing the wrong surfactant without considering the rock mineralogy may result in high adsorption on the pore surface of the rock and unnecessary waste of resources.It is also worthy to note that surfactants are some of the most expensive chemicals used during EOR.Extensive literature review suggests that anionic surfactant are the preferred surfactant category for EOR especially when it comes to sandstone reservoirs.Occasionally,in specific situations a better performance have been reported after injecting cationic,non-ionic or mixtures of both surfactants,particularly when dealing with carbonate reservoirs.This paper presents in detail a review of the most commonly applied surfactants in EOR studies and the optimum application criteria for of each type.To the best of the authors'knowledge,such detailed and comprehensive review is not available in the literature,presently.
文摘Surfactant enhanced oil recovery(EOR)includes surfactant flooding and surfactant stimulation.The main functions of surfactants are to reduce interfacial tension and wettability alteration.This paper is to review the EOR technology related to surfactant injection.The reviewed topics include the following:Surfactant EOR mechanismsFactors affecting interfacial tension Trapping numberScreening criteriaLaboratory work Numerical simulation work Summary of pilot and large-scale applications Surfactants used Salinity gradientSurfactant EOR in carbonate reservoirs Surfactant EOR in shale reservoirs.
基金This research was supported by the United Fund Project of National Natural Science Foundation of China(Grant No.U1262209)the National Natural Science Foundation of China(NSFC)(Grant No.51274172).
文摘As a serious problem in drilling operation,wellbore instability restricts efficient development of shale gas.The interaction between the drilling fluid and shale with hydration swelling property would have impact on the generation and propagation mechanism of cracks in shale formation,leading to wellbore instability.In order to investigate the influence of the hydration swelling on the crack propagation,mineral components and physicochemical properties of shale from the Lower Silurian Longmaxi Formation(LF)were investigated by using the XRD analysis,cation exchange capabilities(CEC)analysis,and SEM observation,and we researched the hydration mechanism of LF shale.Results show that quartz and clay mineral are dominated in mineral composition,and illite content averaged 67%in clay mineral.Meanwhile,CEC of the LF shale are 94.4 mmol/kg.The process of water intruding inside shale along microcracks was able to be observed through high power microscope,meanwhile,the hydration swelling stress would concentrate at the crack tip.The microcracks would propagate,bifurcate and connect with each other,with increase of water immersing time,and it would ultimately develop into macro-fracture.Moreover,the macrocracks extend and coalesce along the bedding,resulting in the rock failure into blocks.Hydration swelling is one of the major causes that lead to wellbore instability of the LF shale,and therefore improving sealing capacity and inhibition of drilling fluid system is an effective measure to stabilize a borehole.
基金The authors would like to acknowledge the support of VFSTR(Deemed to be University),Guntur,India.
文摘The energy resources mainly petroleum and petroleum hydrocarbons are major pollutants of the environment.The oil and oil products contamination may cause severe harm and hence,the attention has been remunerated in the development of alternative technologies for elimination of these contaminants.Biosurfactants were used in the remediation of oil pollution due to advantages such as biodegradability and low toxicity.The biosurfactants are produced from low cost substrates like agro-industrial wastes which reduce the cost of production.Biosurfactants and bioemulsifiers are amphiphilic compounds and are produced as extracellular or a part of the cell membrane by bacteria.The insight view,how hydrocarbons are degraded by microorganisms and thereby reduce the damage of ecosystem is highly essential to target the problem.Biofilms are the bacterial communities which protects the bacterial cells from various adverse conditions.The present review describes the biosurfactants and its synthesis from bacteria and also emphases on the role of surfactants in oil remediation.
文摘This paper deals with the comparison of models for predicting porosity and permeability of oil reservoirs by coupling a machine learning concept and petrophysical logs.Different machine learning methods including conventional artificial neural network,genetic algorithm,fuzzy decision tree,the imperialist competitive algorithm(ICA),particle swarm optimization(PSO),and a hybrid of those ones are employed to have a comprehensive comparison.The machine learning approach was constructed and tested via data samples recorded from northern Persian Gulf oil reservoirs.The results gained from the machine learning models used in this paper are compared to the relevant real petrophysical data and the outputs achieved by other methods employed in our previous studies.The average relative absolute deviation between the approach estimations and the relevant actual data is found to be less than 1%for the hybridized approaches.The results reported in this paper indicate that implication of hybridized machine learning methods in porosity and permeability estimations can lead to the construction of more reliable static reservoir models in simulation plans.
文摘The application of distributed temperature sensors(DTS)to monitor producing zones of horizontal well through a real-time measurement of a temperature profile is becoming increasingly popular.Those parameters,such as flow rate along wellbore,well completion method,skin factor,are potentially related to the information from DTS.Based on mass-,momentum-,and energy-balance equations,this paper established a coupled model to study on temperature distribution along wellbore of fracturing horizontal wells by considering skin factor in order to predict wellbore temperature distribution and analyze the factors influencing the wellbore temperature profile.The models presented in this paper account for heat convective,fluid expansion,heat conduction,and viscous dissipative heating.Arriving temperature and wellbore temperature curves are plotted by computer iterative calculation.The non-perforated and perforated sections show different temperature distribution along wellbore.Through the study on the sensitivity analysis of skin factor and flow rate,we come to the conclusion that the higher skin factor generates larger temperature increase near the wellbore,besides,temperature along wellbore is related to both skin factors and flow rate.Temperature response type curves show that the larger skin factor we set,the less temperature augmenter from toe to heel could be.In addition,larger flow rate may generate higher wellbore temperature.
文摘The development of shale reservoirs has brought a paradigm shift in the worldwide energy equation.This entails developing robust techniques to properly evaluate and unlock the potential of those reservoirs.The application of Nuclear Magnetic Resonance techniques in fluid typing and properties estimation is well-developed in conventional reservoirs.However,Shale reservoirs characteristics like pore size,organic matter,clay content,wettability,adsorption,and mineralogy would limit the applicability of the used interpretation methods and correlation.Some of these limitations include the inapplicability of the controlling equations that were derived assuming fast relaxation regime,the overlap of different fluids peaks and the lack of robust correlation to estimate fluid properties in shale.This study presents a state-of-the-art review of the main contributions presented on fluid typing methods and correlations in both experimental and theoretical side.The study involves Dual Tw,Dual Te,and doping agent's application,T1-T2,D-T2 and T2sec vs.T1/T2 methods.In addition,fluid properties estimation such as density,viscosity and the gas-oil ratio is discussed.This study investigates the applicability of these methods along with a study of the current fluid properties correlations and their limitations.Moreover,it recommends the appropriate method and correlation which are capable of tackling shale heterogeneity.
文摘Nanotechnology has attracted a great attention in enhancing oil recovery(EOR)due to the costeffective and environmental friendly manner.The size of nanoparticles for EOR usually is in a range of 1e100 nm,which may slightly differ from various international organisations.Nanoparticles exhibit significantly different properties compared to the same fine or bulk molecules because of much higher concentration of atoms at their surface as a result of ultra-small size.In particular,one of the most useful and fascinating properties of these particles is to creating a massive diffusion driving force due to the large surface area,especially at high temperatures.Previous studies have shown that nanoparticles can enhance oil recovery by shifting reservoir wettability towards more water-wet and reducing interfacial tension,yet this area is still open for discussion.It is worth noting that the potential of nanoparticles to reduce the oil viscosity,increase the mobility ratio,and to alter the reservoir permeability has not been investigated to date.Depending on the operational conditions of the EOR process,some nanoparticles perform more effectively than others,thus leading to different levels of enhanced recovery.In this study,we aim to provide a summary on each of the popular and available nanoparticles in the market and list their optimum operational conditions.We classified nanoparticles into the three categories of metal oxide,organic and inorganic particles in this article.
文摘The EOR techniques are employed to recover more oil from mature reservoirs after the primary and secondary oil production stages.Polymer flooding as a chemical EOR method involves adding polymer molecules in order to increase water viscosity.Increasing water viscosity will improve the mobility ratio of injected fluid to reservoir fluid toward a more favorable value.Therefore,vertical and areal sweep efficiencies are increased compared to typical water flooding.Polymer flooding will be most effective if applied in the early stages of a water flood while the mobile oil saturation is still high.Polymer is also a critical component when considering other chemical EOR technologies such as alkaline-polymer or alkaline-surfactant-polymer.The present study covers two main parts.In the first part,fundamental of polymer flooding as it related to experimental work and simulation are discussed.The challenge of polymer flooding applications in high temperature and high salinity(HTHS)environment is also discussed in this part.In the second part,the synergy of polymer with surfactant and alkaline as chemical enhancing oil recovery(CEOR)methods is discussed.
基金The authors express their profound gratitude to the University of Oklahoma for granting the permission to publish this work.
文摘The application of nanotechnology in the oil and gas industry is on the rise as evidenced by the number of researches undertaken in the past few years.The quest to develop more game-changing technologies that can address the challenges currently facing the industry has spurred this growth.Several nanoparticles,of different sizes and at different concentrations,have been used in many investigations.In this work,the scope of the study covered the application of nanotechnology in drilling and hydraulic fracturing fluids,oilwell cementing,enhanced oil recovery(which includes transport study,and foam and emulsion stability),corrosion inhibition,logging operations,formation fines control during production,heavy oil viscosity reduction,hydrocarbon detection,methane release from gas hydrates,and drag reduction in porous media.The observed challenges associated with the use of nanoparticles are their stability in a liquid medium and transportability in reservoir rocks.The addition of viscosifier was implemented by researchers to ensure stability,and also,surface-treated nanoparticles have been used to facilitate stability and transportability.For the purpose of achieving better performance or new application,studies on synergistic effects are suggested for investigation in future nanotechnology research.The resulting technology from the synergistic studies may reinforce the current and future nanotechnology applications in the oil and gas industry,especially for high pressure and high temperature(HPHT)applications.To date,majority of the oil and gas industry nanotechnology publications are reports of laboratory experimental work;therefore,more field trials are recommended for further advancement of nanotechnology in this industry.Usually,nanoparticles are expensive;so,it will be cost beneficial to use the lowest nanoparticles concentration possible while still achieving an acceptable level of a desired performance.Hence,optimization studies are also recommended for examination in future nanotechnology research.
文摘This paper reviews the utilization of Big Data analytics,as an emerging trend,in the upstream and downstream oil and gas industry.Big Data or Big Data analytics refers to a new technology which can be employed to handle large datasets which include six main characteristics of volume,variety,velocity,veracity,value,and complexity.With the recent advent of data recording sensors in exploration,drilling,and production operations,oil and gas industry has become a massive data intensive industry.Analyzing seismic and micro-seismic data,improving reservoir characterization and simulation,reducing drilling time and increasing drilling safety,optimization of the performance of production pumps,improved petrochemical asset management,improved shipping and transportation,and improved occupational safety are among some of the applications of Big Data in oil and gas industry.Although the oil and gas industry has become more interested in utilizing Big Data analytics recently,but,there are still challenges mainly due to lack of business support and awareness about the Big Data within the industry.Furthermore,quality of the data and understanding the complexity of the problem are also among the challenging parameters facing the application of Big Data.
文摘Cusp displacement catastrophe theory can be introduced to propose a new method about instability failure of the interbed for gas storage cavern in bedded salt in solution mining.We can calculate initial fracture drawing pace of this interbed to obtain 2D and 3D gas storage shapes at this time.Moreover,Stability evaluation of strength reduction finite element method(FEM)based on this catastrophe theory can used to evaluate this interbed stability after initial fracture.A specific example is simulated to obtain the influence of the interbed depth,cavern internal pressure,and cavern building time on stability safety factor(SSF).The results indicate:the value of SSF will be lower with the increase of cavern building time in solution mining and the increase of interbed depth and also this value remains a rise with the increase of cavern internal pressure Especially,we can conclude that the second-fracture of the interbed may take place when this pressure is lower than 6 MPa or after 6 days later of the interbed after initial fracture.According to above analysis,some effective measures,namely elevating the tube up to the top of the interbed,or changing the circulation of in-and-out lines,can be introduced to avoid the negative effects when the secondfracture of the interbed may occur.
文摘Greater complexity is involved in the transient pressure analysis of horizontal oil wells in contrast to vertical wells,as the horizontal wells are considered entirely horizontal and parallel with the top and underneath boundaries of the oil reserve.Therefore,there is an essential need to estimate productivity of horizontal wells accurately to examine the effectiveness of a horizontal well in terms of technical and economic prospects.In this work,novel and rigorous methods based on two different types of intelligent approaches including the artificial neural network(ANN)linked to the particle swarm optimization(PSO)tool are developed to precisely forecast the productivity of horizontal wells under pseudo-steady-state conditions.It was found that there is very good match between the modeling output and the real data taken from the literature,so that a very low average absolute error percentage is attained(e.g.,<0.82%).The developed techniques can be also incorporated in the numerical reservoir simulation packages for the purpose of accuracy improvement as well as better parametric sensitivity analysis.
基金This work has been supported by Turkish Scientific and Technological Research Council(Project Number:111A016).Authors gratefully acknowledge the financial support.
文摘Amines are well-known for their reversible reactions with CO_(2),which make them ideal for CO_(2) capture from several gas streams,including flue gas.In this respect,selective CO_(2) absorption by aqueous alkanolamines is the most mature technology but the process is energy intensive and has also corrosion problems.Both disadvantages can be diminished to a certain extent by chemical adsorption of CO_(2) selectively.The most important element of the chemical adsorption of CO_(2) involves the design and development of a suitable adsorbent which consist of a porous support onto which an amine is attached or immobilized.Such an adsorbent is often called as solid amine sorbent.This review covers solid amine-based studies which are developed and published in recent years.First,the review examines several different types of porous support materials,namely,three mesoporous silica(MCM-41,SBA-15 and KIT-6)and two polymeric supports(PMMA and PS)for CO_(2) adsorption.Emphasis is given to the synthesis,modifications and characterizations-such as BET and PXRD data-of them.Amination of these supports to obtain a solid amine sorbent through impregnation or grafting is reviewed comparatively.Focus is given to the adsorption mechanisms,material characteristics,and synthesis methods which are discussed in detail.Significant amount of original data are also presented which makes this review unique.Finally,relevant CO_(2) adsorption(or equilibrium)capacity data,and cyclic adsorption/desorption performance and stability of important classes of solid amine sorbents are critically reviewed.These include severa PEI or TEPA impregnated adsorbents and APTES-grafted systems.
文摘In recent years,controlling the salinity and composition of the injected water has become an emerging enhanced oil recovery(EOR)technique,often described as low salinity(LS)waterflooding.This work is done with the intention to contribute to the ongoing discussions about LS waterflooding mechanism(s).For this purpose,a series of different experiments were conducted.At first,the effect of salinity on the interfacial tension(IFT)and the contact angle was evaluated with a crude oil sample.Then to achieve more accurate results in observing oil/water interface,similar IFT experiments were also carried out on a synthetic oil containing asphaltenes.Thereafter,microscopic visualization using glass micromodel was performed on the interface of the synthetic oil sample and brines.Four brine solutions including Sea Water(SW),it's dilutions and formation water(FW)were used for various experiments.Finally,to investigate the presented mechanism by other authors,a series of Environmental Scanning Electron Microscopy(ESEM)analysis on the synthetic oil was carried out to understand better the phase behaviour after contacting both synthetic oil and water phases from the micromodel experiment.Based on the existing mechanism,there exists an optimal concentration beyond which dilution is no longer an effective process.
文摘Due to the high viscosity of heavy crude oils,production from these reservoirs is a demanding task.To tackle this problem,reducing oil viscosity is a promising approach.There are various methods to reduce viscosity of heavy oil:heating,diluting,emulsification,and core annular flow.In this study,dilution approach was employed,using industrial solvents and gas condensate.The viscosity of two Iranian heavy crude oils was measured by mixing with solvents at different temperatures.Dilution of both oil samples with toluene and heptane,resulted in viscosity reduction.However,their effect became less significant at higher concentrations of diluent.Because of forming hydrogen bonds,adding methanol to heavy crude oil resulted in higher viscosity.By adding condensate,viscosity of each sample reduced.Gas condensate had a greater impact on heavier oil;however,at higher temperatures its effect was reduced.Diluting with naphtha decreased heavy oil viscosity in the same way as n-heptane and toluene.Besides experimental investigation,different viscosity models were evaluated for prediction of heavy oil/solvent viscosity.It was recognized that Lederer'model is the best one.
基金The authors gratefully acknowledge the financial support from NSFC(National Natural Science Foundation of China)(No.51374044)The National Basic Research Program(973)of China(No.2010CB226705)Chinese State Municipal Science and Technology Project(No.2011ZX05018-005).
文摘Nanoparticles have been widely used to reduce wellbore instability problems of shale formation.In this paper,nanoparticle-containing water-based drilling fluids(WBDFs)and oil-based drilling fluids(OBDFs)were evaluated by running three new tests including spontaneous imbibition,swelling rate and acoustic transit time.Results showed that,for the WBDFs,nanoparticles leaded to higher plastic viscosity(PV)and yield point(YP),and lower API-filtration.Moreover,because pore throats of shale can be plugged by nanoparticles,imbibition amount,swelling rate,and Young's-modulus reduction of shale decreased significantly.Higher concentration of nanoparticles can induce better plugging effect.However,for the OBDFs,nanoparticles did not show these positive effects like the nano WBDFs,even leaded to some negative effects such as higher filtration and larger Young'smodulus reduction.The main reasons are that the silica nanoparticles can easily disperse in the WBDFs,and effectively prevent the filtrate invading into shale by plugging pore throats.But the same silica nanoparticles are difficult to disperse in OBDFs,and do not perform the expected functions.This study indicates that nano WBDFs have great potential to reduce the wellbore instability problems of shale formation.
