The effect of nanosilica sizes in the presence of nonionic TX100 surfactant on CO_(2)foam flooding

The aim of this research is to study the effect of hydrophilic silica nanoparticles,sizes as CO_(2) foam stabilizer in the presence of nonionic TX100 surfactant.Two nanosilica sizes,15 and 70 nm,have been examined thoroughly.Physisorption of TX100 on silica nanoparticles(nanosilica)was characterized by adsorption isotherm and surface tension measurement,while CO_(2) foams stability was quantified based on their foamability,foam stability,particle partitioning in the foams,and bubble sizes.Results show that direct contact of TX100 with nanosilica does altered the wettability of hydrophilic nanosilica surface,enable them to lengthen CO_(2) foams life at certain surfactant and nanoparticles concentrations.For 15 nm nanosilica,CO_(2) foam stability shows excellent performance at 0.1 and 0.5 wt%TX100 concentrations.As for 70 nm nanosilica,CO_(2) foam demonstrates longer lifetime at much lower TX100 concentration,0.01 wt%.Without the presence of TX100,CO_(2) foams exhibit undesirable lifetime performances for both nanosilica sizes.Nanosilica partitioning in CO_(2) foams structures demonstrate consistent relation with contact angle measurement.Estimated bubble sizes shows insignificant effect on CO_(2) foams life.With the assists of nanosilica and TX100,enhanced oil recovery via CO_(2) foam injection succeeds in increasing oil production by 13e22%of original oil-in-place(OOIP).

Study on the influence of fracture lengths and fracture angles on residual oil distribution based on the slab model

After fracturing in the pilot area,channeling occurs at a low fracture angle(15).Based on the resistance-water saturation relationship,three-dimensional physical simulation methods are used in the laboratory to study the effect of different fracture angles and lengths on the residual oil distribution during the displacement process.Meanwhile,recovery percent,displacement efficiency and expanding sweep co-efficient to the improvement of recovery percent are also discussed.The results show that the fracture angle and length are closely related to the oil saturation distribution in these models.As the fracture angle increases,the sweep coefficient decreases(0.2412→0.1463),and the recovery percent also in-creases(46.16→56.88%),but the extent of increase has been reduced(7.96→2.96%).The extension of the fracture length is more prone to have a cross-flow phenomenon;the sweep coefficient is reduced(0.2412→0.1463).Compared to the model with 1/2 oil-water well spacing,the recovery percent is decreased by 14.29%.In different fracture models,the increasable sweep coefficient has a greater impact on oil recovery than the increasable displacement efficiency(71.30→28.70%).

The effect of type waves on vibroseismic implementation of changes properties of rock, oil viscosity, oil compound composition, and enhanced oil recovery

Based on the results of laboratory studies,the frequency of 35 Hz in longitudinal waves and 20 Hz in circular waves is the optimum frequency that can increase the maximum oil recovery.Coreflooding test results before the vibration effect can increase oil production by 51.96%and reduce the residual oil saturation by 59.03%The surprising results when the vibration effect was applied to the coreflooding test method with P wave types continuously succeeded in increasing oil production by 60.54%,inter-mittent P waves by 63.53%and circular waves by 64.76%,while also reducing Sor by 48.49%in continuous P waves,intermittent P waves at 44.81%and C waves at 43.3%,The P wave type vibrational method has an increase in oil gain by 16%,intemittently by 22%,Sor reduction by 18%and 24%,in circular wave oil gain increases by 25%,and Sor decreases by 27%from before the vibration effect given.Besides vibration can change the physical properties of rocks,among others;permeability has increased by 7%using P waves continuously,intermittently by 31%and C waves by 4%;porosity of 5.88%with P waves contin-uously,intermittently of 6.46%and circular waves of 4.63%;grain size before vibration of 45.16 um after vibration using continuous P waves of 42.01μum,intermittently of 4798μum,and circular of 50.46μum;changes in oil composition to contain more alkanes,and lack of aromatic compounds;oil viscosity increased by 3%with continuous P waves,intermittent of 5%,and circular 61%.The new point from this paper is analyzing the vibroseismic effect by using SEM images in terms of the watershed segmentation of the Rabbani algorithm compared to lab results,which have an error rate of under 2%,and a review of oil composition by the GC-MS method.

Reservoir formation conditions and key exploration & development technoloiges in the Yingdong Oilfield in western Qaidam Basin

Located in east part of Yingxiongling structural belt in the Qaidam Basin,the Yingdong oilfield has a extremely complicated ground condition.Due to no significant discovery,this oilfield was considered to have no favorable geologic conditions for formation of oil or gas reservoir.In the past few years,with continuous improvement in the mountain 3D seismic surveys and logging data interpretation,some breakthroughs were obtained in 2010,and the Yingdong oilfield,the largest-scale reserves of a single reservoir with highest organic matter abundance,most favorable physical property and optimal development efficiencies in the Qaidam Basin,had been discovered,the production capacity was up to 0.55×10^(6) t.Through detailed analyses of the Yingdong oilfield,some studies,such as hydrocarbon accumulation conditions and technical challenges,are carried out,and following conclusions can be achieved.The Yingxiongling area is located in Mangya hydrocarbon-generation sag in the west part of the Qaidam Basin,its oil sources are rich;the Neogene Xiayoushashan Formation and Shangyoushashan Formation are dominated by wide and gentle delta frontdshore-shallow lacustrine sediments with interbeds of sandstone and mudstone,the sandbodies are widely distributed with favorable physical condition,and the mudstone is the key caprock,combined with high-quality Paleogene hydrocarbon source rocks,a complete source-reservoir-cap assemblage can be formed.Large-scale detachment faults of the Yingdong area connect high-quality Paleogene hydrocarbon source rocks with middle-shallow buried structural traps,thus,reservoirs formed in the early stage are modified,and at the same time,hydrocarbons formed in the later stage continue to migrate and accumulate;in this way,the deep and shallow faults form a relay-style hydrocarbon transport system,and hydrocarbons are accumulated in the shallow structural traps in the later stage;in this area,the middle-shallow faults have good lateral plugging performance which is favorable for preservation of oil and gas.For complex landforms and reservoir features in the Yingdong area,the integral 3D seismic acquisition,processing and interpretation technology is developed for complex mountain areas to provide a reliable foundation for hydrocarbon exploration.For some problems in the Yingdong oilfield like long oil/gas-bearing intervals,great diffi-culty in identification of fluids,the development mode of multiple oil/gas/water systems in the long intervals is established,and the geologic modeling technology with constraint of multiple conditions on complex fault blocks is also developed.Thus,hydrocarbon accumulation mechanism in the Yingdong oilfield is clear,and some complex key technology of engineering are well solved,providing necessary geologic theories and technical supports for high-efficiency development and rapid production construction in the Yingdong oilfield.

Hydrocarbon accumulation in the deep waters of South China Sea controlled by the tectonic cycles of marginal sea basins

The tectonic cycle of the marginal sea basins in South China Sea(SCS)includes two cycles,i.e.,the formation and contraction of Palaeo-SCS and Neo-SCS.The northern part of SCS is a rift basin on a passive continental margin,while the the Nansha Block is a drifting rift basin.The southern part is a compound compressional basin on an active continental margin;the western part is a shear-extensional basin on a transform continental margin;the eastern part is an accretionary wedge basin on a subduction continental margin.The deep-water basins are mainly distributed on the continental slope and the the Nansha Block.There are three sets of source rocks in the deep-water areas of the northern continental margin in SCS,i.e.,Eocene terrestrial facies,early Oligocene transitional facies and late Oligocene marine facies.A set of Late Cretaceous-Early Oligocene terrestrial marine facies source rocks are developed in the drift-rift basin of SCS.Three sets of Oligocene,early Miocene and Mid-Miocene marine-terrestrial transitional facies source rocks are developed in the deep-water areas of both the southern and western continental margins of SCS.Four sets of reservoirs developed in the northern deep waters of SCS are dominated by deep sea fans.Two sets of reservoirs developed in the the Nansha Block are dominated by delta and biogenic reef.The southern part of SCS is dominated by deep sea fan and biogenic reef.Reservoirs of large channels and other clastic facies were developed in front of the estuaries,while biogenic reef bank was formed in the uplift zone.The hydrocarbon accumulation assemblages are mainly presented as Oligocene-Pliocene in the deep waters on the northern continental margin of SCS,Eocene-Lower Oligocene in the the Nansha Block,Oligocene-Pliocene and Oligocene-Miocene in the deep waters on the southern and western continental margin of SCS,respectively.The major hydrocarbon reservoir types in the deep waters of SCS are related to structural traps,deep water fans and biogenic reefs.The formation of basin,hydrocarbon and reservoir in the deep waters of SCS are controlled by the tectonic cycles of the marginal sea basins,revealing a great potential for hydrocarbon exploration.

Impact of interfacial tension on oil-water flow in a narrow gap

Numerous researchers have examined the co-current flow of oil-water and aqueous solutions containing polymers and surfactants in thin gaps for oil recovery.While some have focused on charges and forces at the interfaces of oil-surfactant solutions during flow.The study of flow structures,interface behavior,and relative permeabilities of oil and aqueous phases of surfactant flow through thin gaps has been less explored.For the first time,this research aims to comprehensively investigate the flow of oil-water and oil-surfactant solutions through a thin gap(Hele-Shaw cell)with a particular focus on the impact of sodium dodecyl sulfate(SDS).The experiments reveal that SDS forms an emulsion near the oil-water interface,capturing oil droplets and enabling their flow along with the SDS solution.Microscopic studies confirm this,showing that when SDS contacts oil,it creates channels through the oil phase,leading to the accumulation and division of oil into small round-shaped droplets,resulting in an oil-in-water emulsion.The addition of SDS to the injecting water significantly enhances relative permeabilities,leading to a remarkable 90%increase in oil recovery from the cell.The research suggests that the optimal SDS concentration range for maximum oil recovery is between 1.5 and 2 wt%,as it achieves the minimum interfacial tension between oil and water.

NMR chemical shifts of carbon atoms and characteristic shift ranges in the oil sample

Application of high resolution^(13)C nuclear magnetic resonance(NMR)spectroscopy to characterize crude oil was demonstrated.The chemical shifts of^(13)C NMR functional groups that determine the composition of the oil sample were determined.Molar fractions of primary,secondary,quaternary,tertiary,aromatic groups,aromatic factor and average hydrocarbon chain length of aliphatic hydrocarbons of the oil sample according to^(13)C NMR spectra were determined.Detailed description of the^(13)C NMR spectra of the oil sample using a single consideration of three NMR spectra:^(13)C,^(13)C Attached Proton Test(APT),^(13)C with Gated Decoupling(GD)was performed.The different contribution of the studied oil sample in the aliphatic(10e75 ppm)and aromatic(115e165 ppm)areas of the^(13)C NMR spectra was determined.The presence of all major hydrocarbon components in the studied oil sample was established on the quantitative level,the aromaticity factor and the mean length of the hydrocarbon chain were evaluated.Quantitative fractions of aromatic molecules and functional groups constituting oil hydrocarbons were determined.In this work we demonstrate that the attached proton test and gated decoupling^(13)C NMR spectroscopy can afford all information to complete the chemical shift assignment of an oil sample,especially for determination of long range 1He^(13)C coupling constants and^(13)C multiplicity.

Experimental study and field application of appropriate selective calculation methods in gas lift design

The most common way to achieve an enormous production rate of a reservoir is to increase drawdown pressure during the production procedure by decreasing the bottom-hole pressure.This process was done by artificial patterns like a gas lift.Nowadays,most of the wells worldwide due to years of production and reducing the amount of energy which was supplied by natural drive mechanisms are being placed on artificial lift methodologies.Hence,the number of wells that used this method will continue to increase.The primary purposes in the gas lift design of a wellbore are to determine the proper depths and the location of valve installation,select appropriate flow regime during the pipeline and calibrate the pressures of the operating and unloading valves.The purpose of this research is to design gas lift system in the oil wells of on the south fields of Iran by considering the maximum production connate water volume of 40 percent and average pressure drop(20-25 psia)throughout the year regarding production continuously or increasing the flow rate of the wells.Therefore,20 wells that their number starts A to T with this locations L280N,W115S and W002S are the candidates for gas lift procedures.Furthermore,the appropriate flow regimes through the well are being studied,and the most proper method for gas lifting and required surficial equipment will be designed for this field.Consequently,due to increasing the volume of gas and connate water among the production after gas lifting,fundamental changes on the equipment,flow regimes and gas lift system are being proposed that production will be done by proper engineering method.In the well gas lift design,Beggs&Brill Revised method is being selected for hydraulic calculation of pipeline flow due to low errors.

A compositional function hybridization of PSO and GWO for solving well placement optimisation problem

Advances in technology and optimisation are helping to improve decision making in the oil and gas industry.However,most of the traditional metaheuristic algorithms applied in well placement optimisation problems suffer from extensive parameter experimentations and local optimum trapping issues.This couples with the complex and heterogeneous nature of hydrocarbon reservoirs and increased decision variables poses severe simulation process demands.This study considered a functional composition integration approach to formulate a robust hybrid metaheuristic algorithm called HGWO-PSO.The HGWO-PSO leverages on the strengths of Grey Wolf Optimiser(GWO)and Particle Swarm Optimisation(PSO)and the Clerc's parameter setting considerations.A rigorous approach which enforces regulatory agreed minimum well spacing was incorporated in the optimisation process.Reservoir models ranging from unimodal to multimodal spatial systems were used as examples to test the explorative and exploitative capabilities of the algorithms.In this paper we show the performance curve and statistical analysis of HGWO-PSO as a well placement algorithm and compares its performance with that of standalone PSO,and GWO and the traditional Genetic Algorithm(GA).Results revealed that the HGWO-PSO demonstrated comparative performances in terms of exploration and exploitation obtaining the best optimal solutions which give highest contractor's NPVs in majority of cases considered.Again,the means and standard deviations for HGWO-PSO among the various runs showed consistent and efficient performance.The Wilcoxon signed rank test conducted gave very low p-values suggesting uniqueness of HGWO-PSO from the other metaheuristic variants.Additionally,the computational speed of HGWO-PSO was relatively better as compared to the individual GWO and PSO in most the test cases.The simulation results for all test cases confirm that implementation of HGWO-PSO can cause considerable improvement in locations of wells even in heterogeneous reservoirs.

Advances in the origin of overpressures in sedimentary basins

Much progress in the studies on overpressuring mechanisms has been made during the past one to two decades.(1)The causes of overpressure are divided into five categories,namely,disequilibrium compaction,fluid expansion,diagenesis,tectonic compression and pressure transfer.The fluid expansion involves hydrocarbon generation,oil cracking to gas and hydrothermal expansion.The diagenesis includes smectite-to-illite transformation.(2)Six methods for identifying overpressure origin are proposed,including log curves combination analysis,Bowers method(loading-unloading diagram),velocitydensity crossplotting,correlation of porosities,pressure calculation and correlation,and comprehensive analyses.(3)With more and more application of empirical methods in the study of overpressure formation,almost all of the overpressure cases that are traditionally thought to be caused by disequilibrium compaction are denied totally or partly.Instead,the hydrocarbon generation is demonstrated to be the most significant mechanism for overpressure formation;the clay diagenesis(especially the smectiteillite transformation)as well as tectonic compression and pressure transfer are also important for overpressure formation.In addition,the overpressure formation in many basins is thought to be influenced by the combination of two or more overpressuring mechanisms.(4)Causes of overpressuring differ in lithology;for mudstones,the overpressure formation in source rocks is usually different from that of non-source rocks,the former of which is frequently related to hydrocarbon generation and sometimes also affected by diagenesis,while the later of which is commonly related to disequilibrium compaction,diagenesis and pressure transfer;for permeable rocks such as sandstones,overpressure is mainly caused by pressure transfer.(5)Because organic matter has an obvious influence on logging parameters such as density and acoustic velocity,an appropriate correction on the content of organic matter is needed when these logging data are used to analyze overpressure formation in organic-rich mudstones.It has been revealed that the cause of overpressuring based on the corrected log data can be quite different from that without correction.

Sedimentary evolution of the Central Canyon System in the Qiongdongnan Basin, northern South China Sea

This study elucidates sedimentary evolution history of the Central Canyon System(CCS),a large axial submarine canyon in the Qiongdongnan Basin(QDNB),northern South China Sea.Thegeomorphological characteristics and infill architectures of the CCS are summarized based on theanalysis of two-and three-dimensional seismic data.Based on a comparative analysis of the CCS indifferent segments and evolutionary stages and in consideration of the tectono-sedimentary conditionsof the QDNB four stages of the sedimentary evolution of the CCS can be divided,i.e.initialdevelopment stage in the Late Miocene(11.6-5.7Ma),erosion-infilling stage in the Early Pliocene(5.7-3.7 Ma),tranquil infilling stage in the Late Pliocene(3.7-1.81 Ma),and rejuvenation stage sincethe Pleistocene(1.81 Ma to present).In the 1ate Middle Miocene(~11.6 Ma),the rudiment of CCswas developed by a regional tectonic transformation in the eastern part of the basin.In the EarlyPliocene,the CCS was further developed from west to east and restrained in the central depressionbelt of the basin due to abundant sediment supplies from the northwestern and northem provenances,the blocking effect of the southern uplift belt,and the restrictive geomorphological features of theeastern part of the basin.In the Late Pliocene,changes in the sedimentary environment resulted in thedevelopment of the CCS in the eastern part of the basin only.Since the Pleistocene,the joint action ofclimatic factors and geomorphological features of the eastern part of the basin led to the rejuvenationof the CCS.

Effect of heterogeneity and injection rates on the recovery of oil from conventional sand packs:A simulation approach

The study of flow through porous media has been of cardinal gravity in oil and gas applications like enhanced oil recovery(EOR),acidizing,fracturing,etc.One of the most anticipated apprehensions is that the core flooding and simulation have become prevalent to understand the flow through porous media.This study aims at simulating and analyzing the effect of alkaline surfactant flooding through heterogeneous permeability conditions in the lab-scale methods.The conventional methods of core flood deal with the effective permeability of the system without considering the effect of heterogeneity within the core.The heterogeneous studies are conducted by simulating a finely meshed 2-D axisymmetric model of the sand pack.The novel Karanj oil surfactant extracted from Pongamia Pinnata,and partially hydrolyzed polyacryl amide polymer are considered for the physicochemical properties of displacing fluid used in the simulations.Different heterogeneity combinations and displacing fluid injection flow rates are introduced for a single absolute permeability system.Results indicate a trend of oil recovery upright with increasing vertical permeability.A lower areal sweep efficiency and early breakthrough are observed in models with high horizontal permeabilities.Further,the effect of heterogeneity on oil recovery is reduced with the increase in injection flow rates of displacing fluid.The present work utilizes computational fluid dynamics to model multiphase flow through a heterogeneous permeability media and its effect on oil recovery.

Accumulation conditions and key technologies for exploration and development of Qinshui coalbed methane field

The Qinshui Basin has been explored for more than 60 years through two stages of oil and gas reconnaissance survey and exploration&development of coalbed methane(CBM),it has become the largest CBM industrialization base in China and also is a model which successfully realize commercialization of CBM of high rank coal-bearing basin in the world.Although the high-rank coal field is characterized by low pressure,low permeability,low saturation and strong heterogeneity,the exploration practice and research show that the accumulation conditions of CBM reservoir in the Qinshui Basin are superior.As main productive intervals,No.15 coal seam of Taiyuan Formation and No.3 coal seam of Shanxi Formation respectively belong to the epicontinental-sea carbonate platform sedimentary system and the epicontinental-sea shallow-water delta sedimentary system.The coal seam has large thickness,and is mostly composed of humic coal and mainly contains vitrinite.Affected by tectonic thermal events in the Yanshanian period,the coal rank is high,the adsorption capacity is strong,and the gas content is large.Formation of the CBM reservoir goes through three stages including two stages of hydrocarbon generation,gas phase transformation and sealing of hydrodynamics and roof and floor.In view of the characteristics of the Qinshui Basin topography and the high rank coal,a series of key technologies for exploration and development are developed,including mountainous region seismic acquisition,processing and interpretation technology,drilling and completion technology of multiple wells,drilling and completion technology of multiple horizontal wells dominated by compound V type,deplugging secondary fracturing stimulation technology,control technology of high rank CBM drainage,and CBM gathering and transportation technology,which effectively supports the scale and industrialization development of high rank CBM in the Qinshui Basin.

Connotation analysis, source-reservoir assemblage types and development potential of unconventional hydrocarbons in China

Through analysis of the connotation of unconventional hydrocarbons,the source-reservoir assemblages of unconventional hydrocarbons are divided into three types,i.e.,source-reservoir neighboring type,source-reservoir integration type,and source-reservoir separation type.The source-reservoir neighboring type resources mainly include tight oil and tight gas with the following formation conditions and characteristics:(1)efficient near-source accumulation close to high-quality source rocks with the pressure difference between source and reservoir as the dynamic force;(2)large-area tight reservoirs with certain porosity,dominated by micro-nanopores of inorganic origin;(3)distributed in depressions and slopes with large hydrocarbon-bearing area and great resource quantity,low abundance and local development of“sweet spots”;(4)weak tectonism.The source-reservoir integration type resources mainly include coalbed methane,shale gas,shale oil and oil shale.The formation conditions and characteristics are:(1)high abundance of organic matter,different types of organic matter and thermal evolution grades leading to formation of different resources types;(2)organic-rich sections are distributed continuously in the reservoiring space which is dominated by nanometer organic pores,interparticle pores and microfissures;(3)hydrocarbons mainly occur in free or adsorbed state,varying much with resource type;(4)the resources are self-conserved,and enriched in depressions and slopes,the conservation conditions are controlled by tectonics,temperature and pressure;(5)the production per well can be enhanced by volume fracturing,which increases the permeability of the reservoirs.The source-reservoir separation type resources are more special,mainly including(1)transformed conventional resources such as oil sand and heavy oil;(2)unsteady resources formed under special conditions of temperature and pressure,among which natural gas hydrate is a representative.These three types of resources in China are different in both development prospect and current situation:(1)the source-reservoir neighboring type is most practical and will develop fast in the next 5 years;(2)the source-reservoir integration type needs continuous exploration and technical breakthrough,and is expected to develop rapidly in the coming decade;(3)in the source-reservoir separation type resources,natural gas hydrates have the greatest development potential,on which technical tests are being conducted.

Coupled tripartite investigation of breaker fluid invasion and impact on hydrocarbon recovery in sandstone reservoirs

Breaker fluids are designed to dissolve filter cakes by breaking their long-chain molecules,thereby removing solid deposits on the wellbore wall.Although breaker fluids are not intended to infiltrate the hydrocarbon reservoir,they can invade and cause formation damage by altering sandstone reservoirs'wettability and relative permeability.This can lead to a reduction in the overall reservoir performance.This study coupled tripartite methods to investigate the potential impact of breaker invasion and transport in hydrocarbon reservoirs and its multiscale effect on the performances of sandstone reservoirs.We utilized experimental,analytical,and numerical methods to assess and predict the susceptibility of reservoirs to breaker fluid invasion and transportation.Our experimental and empirical investigations considered varying breaker fluid formulations to evaluate the effects of breaker fluid concentration,formation temperature,and solution gas-oil ratio(GOR)on residual-oil saturation(ROS)and oil-water relative permeability.By adopting the ROS and relative permeability associated with the 50%v/v breaker fluid mixture,the performance of the hydrocarbon reservoir was numerically simulated under the limiting scenarios of no-invasion,moderate-invasion,and deep-invasion of breaker fluid.The results indicate a positive correlation between breaker fluid concentration and ROS,highlighting the risks that breaker fluid invasion and deep infiltration pose to hydrocarbon recovery.Further,results show that both live-oil condition(LOC)and dead-oil condition(DOC)reservoirs are susceptible to the detrimental impacts of breaker fluid infiltration,while their invasion can reduce hydrocarbon recovery in both LOC(-6%)and DOC(-28%).The multi-scale effects on reservoir performance are more pronounced at near-wellbore and DOC than at far-field and LOC.Findings from this work provide valuable insights into the complexity of breaker-fluid invasion in sandstone reservoirs and the mitigation of associated risks to reservoir performance.

Applications of silica and titanium dioxide nanoparticles in enhanced oil recovery:Promises and challenges

The Surface engineering of nanoparticles has contributed to the development of nanoscience and nanotechnology by designing of new material depends on their surface modifier with series of functional properties and applications.The dispersed nanoparticles can change or modify the interfacial properties in liquid-liquid system in aqueous phase if their surface is modified by ionic surfactant.The interfacial energy in nanoparticles-brine system,the ions tends to modify the transport phenomena in pore channels and improve the recovery.The use of the suspension of the particles at nanoscales can offer some advantages of induced sedimentation stability by surface force easily counter balance the force of gravity.This happened due to their nanosize,nanostructure,high volume to surface ratio and strong rock fluid interaction.It also influences the emulsion stability and alters the surface characteristics of surfactant and polymer within the rock in porous medium.Some of the problems associated with conventional EOR processes have been solved by nanoscience applications due to their potential response to reduce the interfacial tension at low to ultra-low level,wettability reversal and improvement in rheology of formation fluids.The large specific surface area,high reactivity,toughness and other properties of Nanoparticles can immensely improve the oil mobility compare to conventional EOR.This paper updates the latest review,experimental evidences and re-interpretation of past research data and applications in respect of silica and titanium dioxide nanoparticles in different environment within surfactant(s),polymer(s),polymer-surfactant EOR processes.The nanotechnology therefore is an effective and alternate solution to brush up the traditional EOR approach with state of art technology which can revolutionize the total oil and gas industry and can contributes significantly to enhance the economics of oil field industry.

An evaluation workflow for shale oil and gas in the Jiyang Depression, Bohai Bay Basin, China: A case study from the Luojia area in the Zhanhua Sag

Shale oil and gas plays in continental rift basins are complicated and have not been reported elsewhere.In the Luojia area of the Jiyang Depression,an evaluation workflow for shale oil and gas in this continental rift basin is proposed.Based on analysis of oil-and gas-related geological conditions,a favorable area of shale oil and gas can be identified,and a high-frequency sequence stratigraphic framework of the target area can be established,therefore,the spatiotemporal distribution of shale has been elucidated in the Luojia area.According to the rock texture,structure,composition and color,petrographic classification criteria for shale are determined,and well log data are used to demarcate,track and predict high-quality lithofacies.Based on geochemical analyses and physical simulations of hydrocarbon generation,abundance,types and maturity of organic matter are analyzed,furthermore,geochemical parameters criteria of hydrocarbon generation and the characteristics of oil and gas occurrence in shales can be determined.Storage space types,assemblages and evolution characteristics of shale reservoirs are studied through core observation,thin-section analysis,electron microscopy examination and fluorescence spectrometry.Combined with analysis of reservoir physical properties,the reservoir performance is evaluated.A saturation model is established based on core analysis,well-log interpretation and well-test production data.The model is further used for evaluation of the movable hydrocarbon contents and integrated assessment of the oil potential.Finally,the shale oil and gas production capacity and exploration prospects in the Luojia area are forecasted based on the analyses of factors controlling production capacity and the rock fracability.Through an integrated analysis of multi-factors(including the lithofacies,source rocks,reservoir properties,oil saturation,and production capacity),the shales in the Luojia area can be divided into three categories,i.e.,Class I(high porosity-high resistivity),Class II(medium porosity-medium resistivity),and Class III(low porosity-medium resistivity).

Rheology and lubricity characteristics study at different temperatures using synthesized SnO_(2) nanoparticles in KCl free bentonite water base mud

Drilling mud is a major concerning element due to its high operational and economic impact on the drilling process.Various additives are introduced to enhance the efficiency of drilling fluid,but none of them could perfectly achieve their proposed efficacy in drilling operations.Researchers conceived several nanoparticles(NPs)in drilling fluid to dissolve this issue.In a singular instance,commercial tin oxide(SnO_(2))nanoparticles were utilized to analyze the influence of NPs on the rheological and filtration properties of inorganic KCl salt-based drilling fluid.However,the effect of SnO_(2) NPs on mud lubricity characteristics is not studied previously.However,due to the hazardous behavior of KCl,its use is very limited.Thus,we consider a KCl-free bentonite water-based mud to avoid any environmental damages from drilling operations.We also use SnO_(2) NPs that is synthesized in our laboratory by co-precipitation method.In addition to rheological and filtration properties,we also investigate the effect of NPs on mud's lubricity that was not considered in the previous study.Drilling fluid properties are measured at five different NPs concentrations of 0.10,0.25,0.50,0.75&1.0 wt%,and at six different temperatures of 30,40,50,60,70,and 80°C,while filtration properties are measured using API low-pressure low temperature(LPLT)condition.The addition of 0.1 wt%SnO_(2) NPs increases plastic viscosity,yield point,10 s gel strength,and 10 min gel strength by 10%,63%,20%,and 14%,respectively.The maximum reduction in lubricity coefficient is found to be 14%at NPs concentration of 1.0 wt%.The NPs concentration of 0.5 wt%yielded a reduction in fluid loss and mud cake thickness by 8.1%and 34%,respectively.The study suggests that SnO_(2) NPs can be employed as an additive to improve the rheology,lubricity,and filtration properties of KCl-free bentonite water-based drilling mud.

A robust deep structured prediction model for petroleum reservoir characterization using pressure transient test data

A robust deep learning model consisting of long short-term memory and fully connected neural net-works has been proposed to automatically interpret homogeneous petroleum reservoirs having infinite,no flow,and constant pressure outer boundary conditions.The pressure change data recorded during the well test operation along with its derivative is input into the model to perform the classification for identifying the reservoir model and,further,regression to estimate output parameter.Gaussian noise was added to analytical models while generating the synthetic training data.The hyperparameters were regulated to perform model optimization,resulting in a batch size of 64,Adam optimization algorithm,learning rate of 0.01,and 80:10:10 data split ratio as the best choices of hyperparameters.The perfor-mance accuracy also increased with an increase in the number of samples during training.Suitable classification and regression metrics have been used to evaluate the performance of the models.The paper also demonstrates the prediction performance of the optimized model using simulated and actual oil well pressure drawdown test cases.The proposed model achieved minimum and maximum relative errors of 0.0019 and 0.0308,respectively,in estimating output for the simulated test cases and relative error of 0.0319 for the real test case.