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We analyze the effect of wall slip on the fully developed reverse mixed convection of Jeffery nanofluids between two inclined parallel plates with uniform wall heat flux conditions. The theory of tri‐hybrid water‐based nanoparticles with unique shapes, namely, cylindrical (copper), spherical (titanium oxide), and platelet (aluminum oxide) for heat transfer enhancement is utilized since it has better heat performance applicable in a dynamic of fuels and coolant in automobiles as compared with regular Newtonian fluid and nanofluid. The equations describing the above transport phenomena are nondimensional through appropriate scale transformations. Analytical solutions for velocity, temperature, and pressure distributions are obtained. Four different flow regimes including no reversal, bottom reversal, top reversal, and on both walls reversal are found for different combinations of buoyancy and pressure. Particularly, we notice that the wall slip significantly affects flow reversal. Furthermore, we notice that Magyari 's conclusion that the results of the homogeneous nanofluid flow model can be recovered from the corresponding Newtonian fluid model has great limitations. Besides, the effect of several physical factors on velocity and temperature distributions and important physical quantities, including skin friction coefficient and Nusselt number, are analyzed and graphically discussed. [ABSTRACT FROM AUTHOR]

The classic problem of mixed convection flow within an inclined square lid-driven cavity is extended to hybrid nanofluid case. The governed partial differential equations with non-homogeneous boundary conditions are studied by means of our proposed Coiflet wavelet-homotopy method. Highly accurate solutions with very clear vortex structures are obtained. The effectiveness and efficiency of these solutions are strictly checked through a series of comparisons with published ones in literature. Results show that our proposed approach holds both strong nonlinear processing capability and excellent local display characteristics so that it can be used to attack complicated nonlinear problems more efficiently and accurately than the traditional homotopy analysis method and the Coiflet wavelet analysis approach. Besides, physical properties of hybrid nanofluid behaviors are examined, it is noticed that, similar to nanofluids, the hybrid nanofluid is superior to traditional heat transfer fluids for heat transfer enhancement but it could be easier and cheaper. [ABSTRACT FROM AUTHOR]

The mixed convection flow of a hybrid nanofluid in an inclined channel with top wall-slip due to wall stripe and constant heat flux conditions is studied. Explicit analytical solutions are given to the flow velocity, temperature, as well as the pressure in non-dimensional forms. The flow regime domain, the velocity and temperature distributions, and the dependence of various physical parameters such as the hybrid nanoparticle volume fractions, the wall-slip, the Grashof number, the Reynolds number, and the inclined angle are analyzed and discussed. It is found that the hybrid nanofluid delays the appearance of flow reversal on both walls and the wall-slip postpones the flow reversal on the top wall. [ABSTRACT FROM AUTHOR]

The purpose of present work is to explore the features of homogeneous–heterogeneous reactions in peristalsis flow of Carreau magneto hybrid nanofluid with copper and silver nanoparticles in a symmetric channel. The velocity slip condition and thermal radiation effect is also taken in the simplified model. Thermodynamic optimization aspect is discussed through the entropy generation analysis. The proposed mathematical systems are modified by using a lubrication approach and solved by a homotopy-based package-BVPh 2.0. The impacts of different involved parameters on flow characteristics, thermal characteristics, chemically reactive concentration and entropy generation are scrutinized through analytic results. It reveals that the fluid velocity decreases with the increasing values of the Weissenberg and the Hartman numbers. Characteristics of the Brinkman and the thermal radiation numbers are quite reverse for the heat transfer rate. In addition, entropy generation decreases with thermal radiation and Weissenberg number. The main outcome signifies that hybrid nanofluid is better thermal conductor as compared to the conventional nanofluid. [ABSTRACT FROM AUTHOR]

Flow and heat transfer of a nanofluid through a horizontal microchannel in the presence of the magnetic field effects and electric double layer (EDL) is investigated theoretically. For a microchannel with a large aspect ratio, the flow problem is treated as a two-dimensional nonlinear system. The body force generated by the EDL and magnetic field is considered in momentum equation. In order to study the mechanism of nanofluid heat transfer, the nanoparticles distribution and the heat transfer process of nanofluid flow are represented by the Buongiorno's nanofluid model with the passively controlled nanoparticles distribution at the boundary, which has not been considered in previous microchannel studies. Compared to the so-called active control of nanoparticle volume fraction at the boundary, the current approach makes the model physically more reliable by taking into account of the effect due to varying temperature. The analytical approximations obtained by the homotopy analysis method reveals that both the magnetic field effects and the EDL play significant roles on altering the flow and heat transfer in microchannels. It is also found that the heat enhancement is significantly depend on the Brinkman number and the temperature applied to the wall. [ABSTRACT FROM AUTHOR]

The homogeneous and heterogeneous reactions in the boundary-layer of a flat surface are considered. The autocatalysts are assumed to be of regular sizes, while the solution is a dilute nanofluid. The heat release due to the chemical reactions is taken into account. The Buongiorno's model is used to describe the behaviors of this reaction system. This configuration makes the current model be different from all previous publications. Multiple solutions are given numerically to the rescaled nonlinear system, whose stability is verified. The results show that the strength coefficients of the homogeneous and heterogeneous reactions are key factors to cause the appearance of the multiple solutions in the distribution of the chemical reactions. Nanofluids enhance the diffusion of heat and help maintain the stability of chemical reactions. [ABSTRACT FROM AUTHOR]

A modified nanofluid model for homogeneous–heterogeneous reactions in a gravity-driven liquid film is proposed based on the assumptions of the homogeneous reaction governed by isothermal cubic autocatalytic kinetics and the heterogeneous reaction given by first-order kinetics. The Buongiorno model is introduced to describe behaviors of nanofluids with the Boussinesq approximation being used for simplification of the buoyancy term. Multiple solutions are captured, whose stabilities are checked and discussed based on the theory of Sturm–Liouville. The influence of various physical parameters on important physical quantities is presented for different cases, including buoyancy assisting, no buoyancy, and buoyancy opposing. Different from previous studies on chemical reactions in which reactants are presumed in nanometer scale, we assume that the chemical species are of regular size, which react with each other in a nanofluid. This configuration makes our model physically more realistic than previous ones. [ABSTRACT FROM AUTHOR]

A fully developed steady immiscible flow of nanofluid in a two-layer microchannel is studied in the presence of electro-kinetic effects. Buongiorno's model is employed for describing the behavior of nanofluids. Different from the previous studies on two-layer channel flow of a nanofluid, the present paper introduces the flux conservation conditions for the nanoparticle volume fraction field, which makes this work new and unique, and it is in coincidence with practical observations. The governing equations are reduced into a group of ordinary differential equations via appropriate similarity transformations. The highly accurate analytical approximations are obtained. Important physical quantities and total entropy generation are analyzed and discussed. A comparison is made to determine the significance of electrical double layer (EDL) effects in the presence of an external electric field. It is found that the Brownian diffusion, the thermophoresis diffusion, and the viscosity have significant effect on altering the flow behaviors. [ABSTRACT FROM AUTHOR]

In this paper, a fully-developed, immiscible nanofluid flow in a paralleled microchannel in the presence of a magnetic field is investigated. Buongiorno's model is applied to describe the behaviors of the nanofluid flow. Different from most previous studies on microchannel flow, here the pressure term is considered as unknown, which makes the current model compatible with the commonly accepted channel flow models. The influences of various physical parameters on important physical quantities are given. The entropy generation analysis is performed. Variations of local and global entropy generations with the magnetic field parameter, the electric field, and the viscous dissipation parameter under various ratios of the thermophoresis parameter to the Brownian motion parameter are illustrated. The results indicate that the entropy generation rate strongly depends on the thermophoresis and the Brownian motion parameters. Their increase enhances the total irreversibility of entropy generation. [ABSTRACT FROM AUTHOR]

Highlights • The Buongiorno’s nanofluid model is introduced for cavity nanofluid flow. • The buoyancy term is given more concisely. • Non-uniform heating types of practical importance overlooked in literature are presented. • A novel wavelet-homotopy technique is proposed. • Physical mechanisms on cavity flows with various types of heated and lid-driven walls are conducted. Abstract The laminar mixed convection flow in an inclined lid-driven cavity filled with a nanofluid is investigated in the presence of internal heat generation. The two sidewalls of the enclosure are sinusoidally heated while the top and bottom walls are insulted. The Buongiorno’s model that incorporates the effects of Brownian motion and thermophoresis is applied to describe the nanofluid behaviours. Parametrical studies are given on the regimes of the complex flow, temperature and concentration fields. The developed equations are nondimensionalized and then solved numerically by the newly developed wavelet-homotopy technique. Comparisons with previously studies in literature are presented and found to be in excellent agreement. The results of this work indicate that the Grashof number, the slipping parameters, the nanoparticles related parameters, the inclination, the boundary coefficients including amplitude ratios of temperature and concentration, as well as the phase deviation have significant effects on characteristics of the cavity flow. [ABSTRACT FROM AUTHOR]

The homogeneous-heterogeneous reactions for nanofluids flow are developed incorporating the Buongiorno’s nanofluid model, in which the heterogeneous reactions given by isothermal cubic autocatalytic kinetics are assumed to take place on the wall surface, while the homogeneous reactions governed by first order kinetics occur in the ambient fluid. The classical problem of laminar flow in the stagnation region of a plane surface is illustrated as an example to testify the validity of this model. Multiple solutions of this state system are obtained for various physical parameters by means of hysteresis bifurcations. Results show that the ratio of Brownian and thermophoretic diffusivity plays an important role on the appearance of the bifurcation point of multiple solutions, the less this value is, the slower this bifurcation point appears. In other words, nanofluids are expected to alter the transport mechanisms of homogeneous-heterogeneous reactions and therefore have great potentials in applications of the related fields. [ABSTRACT FROM AUTHOR]

The behaviour of microchannel flow of a nanofluid between two parallel flat plates in the presence of the electrical double layer (EDL) is investigated in this paper. The problem is formulated based on the Buongiorno nanofluid model with the electrical body force due to the EDL being considered in the momentum equation. As one of the highlights of the present investigation, the unphysical assumption introduced in previous studies often leading to the discontinuities of flow field that the electrostatic potential in the middle of the channel has to be equal to zero is eliminated. In addition, the inappropriate assumption that the pressure constant is treated as a known condition is also rectified. The new model is developed with the governing equations being reduced by a set of dimensionless quantities to a set of coupled ordinary differential equations. Based on the analytical approximations, the influences of various physical parameters on the flow field and temperature field, and the important physical quantities of practical interests are analysed and discussed in detail. [ABSTRACT FROM AUTHOR]

In this paper, we focus on the two-dimensional pulsating nanofluid flow through a parallel-plate channel in the presence of a magnetic field. The pulsating flow is produced by an applied pressure gradient that fluctuates with a small amplitude. A kind of proper transformation is used so that the governing equations describing the momentum and thermal energy are reduced to a set of non-dimensional equations. The analytical expressions of the pulsating velocity, temperature, and Nusselt number of nanofluids are obtained by the perturbation technique. In the present study, the effects of the Cu-H2O and Al2O3-H2O nanofluids on the flow and heat transfer in pulsating flow are compared and analyzed. The results show that the convective heat transfer effect of Cu-H2O nanofluids is better than that of Al2O3-H2O nanofluids. Also, the effects of the Hartmann number and pulsation amplitude on the velocity, temperature, and Nusselt number are examined and discussed in detail. The present work indicates that increasing the Hartmann number and pulsation amplitude can enhance the heat transfer of the pulsating flow. In addition, selecting an optimal pulsation frequency can maximize the convective heat transfer of the pulsating flow. Therefore, improved understanding of these fundamental mechanisms is conducive to the optimal design of thermal systems. [ABSTRACT FROM AUTHOR]

Previously, the homogenous models were predominant in hybrid nanofluid's studies. However, there is a serious deficiency in these models, that is, the heat transfer coefficients obtained by these models are inconsistent with the experimental results. To overcome this issue, we develop a novel hybrid nanofluid model based on the major slip mechanisms of nanofluids caused by Brownian diffusion and thermophoresis. The problem of flow and heat transfer of a hybrid nanofluid in a lid driven square cavity filled with porous medium is studied as an example to show the correctness and validity of this new model. Numerical results are given by means of the novel Coiflet wavelet homotopy analysis method in the terms of the Brownian motion and thermophoresis. The physical behaviors of hybrid nanofluids flow are discussed in terms of various quantities such as the stream-function, the isotherms, and the Nusselt and Sherwood numbers. The average Nusselt number evaluated with the help of the quadratic multiple regression analysis justifies that the thermophoretic effect is more dominant than the Brownian motion on Nusselt numbers at both walls. [ABSTRACT FROM AUTHOR]

In this paper, the three-dimensional nanofluid bio-convection near a stagnation attachment is studied. With a set of similarity variables, the governing equations embodying the conservation of total mass, momentum, thermal energy, nanoparticles and microorganisms are reduced to a set of fully coupled nonlinear differential equations. The homotopy analysis method (HAM)-finite difference method (FDM) technique is used to obtain exact solutions. The effect of various physical parameters on distribution of the motile microorganisms and the important physical quantities of practical interests are presented and discussed. [ABSTRACT FROM AUTHOR]

An investigation is made for a three-dimensional unsteady mixed nano-bioconvection flow between two contracting or expanding rotating discs. The passively controlled nanofluid model in which Brownian diffusion and thermophoresis are considered as the two dominant factors for nanoparticle/base-fluid slip mechanisms is introduced for description of this flow problem. A novel similarity transformation is introduced so that the governing equations embodying the conservation of total mass, momentum, thermal energy, nanoparticle volume fraction, and microorganisms are reduced to a set of five fully coupled ordinary differential equations. Exact solutions are then obtained analytically for this complex nonlinear system. Besides, the influences of various physical parameters on distributions of velocity, temperature, nanoparticle volume fraction, and the density of motile microorganisms, along with the local Nusselt number and the local wall motile microorganisms flux, are presented and discussed. It is expected that this study can provide a theoretical base for understanding the transport mechanisms of unsteady bioconvection in nanofluids. [ABSTRACT FROM AUTHOR]

In this paper, an investigation is made of the three-dimensional flow and heat transfer of a nanofluid in the boundary-layer region over a flat sheet stretched continuously in two lateral directions. With the help of a series of similarity transformations, this problem is reduced to a set of three coupled differential equations. The homotopy analysis method (HAM) is then applied to derive the explicit solutions for both the velocity and the temperature distributions. A mathematical analysis shows that these solutions decay exponentially at far field. Besides, the influences of the nanoparticle volume fraction ϕ on the velocity and temperature profiles, as well as the reduced local skin friction coefficients and the reduced local Nusselt numbers are studied. It is found that the heat transfer conductivity of the nanofluid is superior to that of the pure fluids. [ABSTRACT FROM AUTHOR]

This article describes the unsteady flow of liquid containing nanoparticles and motile gyrotactic microorganisms between two parallel plates while keeping one moving and other fixed. The passively controlled nanofluid model is used to describe the nanoparticles concentration. Some instances of direct application of this nanofluid bioconvection study can be found in pharmaceutical industry, microfluidic devices, microbial enhanced oil recovery, modeling oil and gas-bearing sedimentary basins and many more. The governing partial differential equations are transformed to ordinary differential equations using the similarity transformations. The mathematica package based on homotopy analysis method is used to solve this problem. The physical phenomenon is explained by drawing the graphs for the temperature, nanoparticles concentration and density of motile microorganisms profiles. Also the tables are given which completely depicts the convergence of gained results. [ABSTRACT FROM AUTHOR]

The influence of stress jump conditions on a steady, fully developed two-layer magnetohydrodynamic electro-osmotic nanofluid in the microchannel, is investigated numerically. A nanofluid is partially filled into the microchannel, while a porous medium, saturated with nanofluid, is immersed into the other half of the microchannel. The Brinkmann-extended Darcy equation is used to effectively explain the nanofluid flow in the porous region. In both regions, electric double layers are examined, whereas at the interface, Ochoa-Tapia and Whitaker's stress jump condition is considered. The non-dimensional velocity, temperature, and volume fraction of the nanoparticle profiles are examined, by varying physical parameters. Additionally, the Darcy number, as well as the coefficient in the stress jump condition, are investigated for their profound effect on skin friction and Nusselt number. It is concluded that, taking into account the change in shear stress at the interface has a significant impact on fluid flow problems. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, an analysis is made for the fully developed mixed bioconvection flow in a horizontal channel filled with a nanofluid that contains both nanoparticles and gyrotactic microorganisms. The passively controlled nanofluid model proposed by Kuznetsov and Nield (2013) is then introduced for modeling this flow problem, which is found to be more physically realistic than previous nanofluid models. Analytical approximations with high precision are obtained by the improved homotopy analysis technique for complicated boundary conditions. Besides, the influences of various physical parameters on the distributions of temperature, the nanoparticle volume fraction, as well as the density of motile microorganisms are investigated in detail. [Copyright &y& Elsevier]

Abstract: The laminar, fully developed mixed convection flow between two paralleled vertical flat plates filled by a nanofluid is investigated. By means of a new set of similarity variables, the governing equations are reduced to a set of three coupled equations with an unknown constant. The exact solutions are obtained by means of the homotopy analysis method for both the buoyancy-assisted and the buoyancy-opposing cases and their accuracies are checked in detail. The effects of the Grashof number Gr and the Prandtl number Pr on the nanofluid flows are then investigated successively. We further consider the effects of the buoyancy ratio Nr, the Brownian motion parameter Nb, the thermophoresis parameter Nt on the pressure parameter σ and the Nusselt number Nu. It is found that the heat transfer characteristic can be improved significantly as the proper nanofluids are applied. [Copyright &y& Elsevier]

Abstract: The unsteady film flow and heat transfer of nanofluids caused by a linear stretching velocity over a horizonal elastic sheet is investigated. By means of similarity variables, the boundary layer equations describing the momentum and energy conservations are reduced to a set of ordinary differential equations with an unknown constant. The homotopy analysis method (HAM) is then applied to give exact solutions for this particular kind of equations. A linear relationship between the film thickness β and the unsteadiness parameter S is found. Besides, the effects of the unsteadiness parameters S, the solid volume fraction of the nanofluid ϕ and the Prandtl number Pr on the velocity and the temperature distributions are presented and discussed, respectively. It is found that the usage of nanoparticles in the base fluids can effectively improve on the heat transfer characteristics. [Copyright &y& Elsevier]

The laminar fully developed nanofluid flow and heat transfer in a horizonal channel are investigated. Highly accurate solutions for the temperature and nanoparticle concentration distributions are obtained. The effects of the Brownian motion parameter N, the thermophoresis parameter N, and the Lewis number Le on the temperature and nanoparticle concentration distributions are discussed. The current analysis shows that the nanoparticles can improve the heat transfer characteristics significantly for this flow problem. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the fully developed mixed convection flow in a vertical channel filled with nanofluids is investigated. Analytical solutions for both the buoyancy-assisted and -opposed flow are obtained. Further analysis shows that the analytical solution for the opposing flow is only valid for a certain region of the Rayleigh number Ra in physical sense. Besides, the effects of the nanoparticle volume fraction φ on the temperature and the velocity distributions are then exhibited. It is confirmed that the nanoparticle volume fraction φ plays a key role for improving the heat and mass transfer characteristics of the fluids. [Copyright &y& Elsevier]

The unsteady mixed convection of a hybrid nanofluid due to rotating disks is examined. The generialzied homogenous flow model that describes hybrid nanofluids containing multiple kinds of nanoparticles is developed for modelling the problem. Its simplified form is proposed based on the linear assumptions and verified by existing model. The argument that the corresponding nanofluid results by the homogenous model can be restored from those solutions of already solved regular problems via simple arithmetic operations is checked. The relation of similarity variables to nanoparticles volumetric fractions is discussed. [ABSTRACT FROM AUTHOR]

A mathematical model is constructed to analyze the mixed convection gravity-driven film flow of nanofluids in the presence of heterogeneous-homogeneous reactions. It is considered that heterogeneous reaction taking place on the surface of plate can be described by isothermal cubic autocatalator kinetics while homogeneous reaction happening at far field is given by first order kinetics. Hysteresis bifurcations incorporating the numerical method is used to obtain the multiple solutions for the system. The uniqueness of this problem lies in the fact that the multiple solutions are possible for the cases of favorable buoyancy ( σ < 0), non-buoyant ( σ  = 0) and unfavorable buoyancy ( σ > 0) for various diffusion coefficients of reactant and autocatalyst. The observed effect of nanofluids on the stability of chemical reactions in the film flow can make this problem practically useful in the related field. [ABSTRACT FROM AUTHOR]

In this paper, we have extended Wang’s (2013) problem of the three-dimensional stagnation flow of a Newtonian fluid on a moving plate with anistropic slip to the case of a nanofluid in suspension of both the nanoparticles and microorganisms. The passively controlled nanofluid model is taken into account to describe this problem, which is believed to be physically more realistic than previously commonly used models. The problem is then reduced by a set of similarity transformations to seven coupled nonlinear ordinary equations with coupled boundary conditions. Numerical solutions are given by means of a very efficient finite difference method. The influences of various physical parameters on the distributions of the velocity, the temperature, the nanoparticle volumetric fraction, the density of motile microorganisms profiles, as well as the local skin friction coefficient, the local Nusselt number, the local wall mass flux and the local density of the motile microorganisms are presented and discussed. [ABSTRACT FROM AUTHOR]

Chang 7 shale reservoir of Ordos Basin has characteristics of low porosity, ultra-low permeability, and low formation pressure coefficient. After hydraulic fracturing, the production of shale oil declines rapidly, and it has no solutions to replenish the formation energy. Currently, a nano variable-viscosity slickwater (named: NSI) is being used in the field for fracturing production. Compared with conventional fracturing fluid systems, the NSI system can increase production of oil wells by more than 4 times, and its economic benefits are very remarkable. The lab experiment shows that NSI system after the gel breaking has ability of enhanced imbibition oil recovery (EIOR), which may be an important stimulation mechanism of the NSI system. However, the contribution of EIOR to oil production is still unclear, and the corresponding mechanism and model are still lacking. Therefore, the fracturing parameters of Changqing Chang 7 reservoir were firstly optimized without considering the imbibition, and two wells were used to carry out field experiments with NSI and conventional slickwater. Then, commercial software is used to predict oil production. It was found that the actual production was higher than the predicted production. To explain this phenomenon, the effect of imbibition on enhanced oil recovery was investigated experimentally under reservoir temperature and pressure. The NMR T 2 spectrum was quantitatively analyzed to clarify the variation of oil and water distribution in different pores of core. The results showed that capillary force was dominant in the small pores of core, and small pores were the main positions of EIOR. Water film was formed in large pores, which increases the migration resistance of the liquid, and allowed gravity to play an obvious role. Finally, based on the modified Aronofsky index model, an EIOR model suitable for the Changqing Chang 7 reservoir was proposed, which achieved a better match between actual production and simulated production of horizontal wells. • NSI fluid has ability of wetting modification and reducing interfacial tension, and shows good effect of EIOR. • Field fracturing parameters of NSI fluid are optimized, and its production is more than 4 times higher than conventional fluid. • Driving force of EIOR in small pores is dominated by capillary force and gravity also benefits imbibition in large pores. • An Aronofsky EIOR model is established, which is suitable for Chang 7 reservoir. [ABSTRACT FROM AUTHOR]

Chang 7 shale reservoir of Ordos Basin has characteristics of low porosity, ultra-low permeability, and low formation pressure coefficient. After hydraulic fracturing, the production of shale oil declines rapidly, and it has no solutions to replenish the formation energy. Currently, a nano variable-viscosity slickwater (named: NSI) is being used in the field for fracturing production. Compared with conventional fracturing fluid systems, the NSI system can increase production of oil wells by more than 4 times, and its economic benefits are very remarkable. The lab experiment shows that NSI system after the gel breaking has ability of enhanced imbibition oil recovery (EIOR), which may be an important stimulation mechanism of the NSI system. However, the contribution of EIOR to oil production is still unclear, and the corresponding mechanism and model are still lacking. Therefore, the fracturing parameters of Changqing Chang 7 reservoir were firstly optimized without considering the imbibition, and two wells were used to carry out field experiments with NSI and conventional slickwater. Then, commercial software is used to predict oil production. It was found that the actual production was higher than the predicted production. To explain this phenomenon, the effect of imbibition on enhanced oil recovery was investigated experimentally under reservoir temperature and pressure. The NMR T 2 spectrum was quantitatively analyzed to clarify the variation of oil and water distribution in different pores of core. The results showed that capillary force was dominant in the small pores of core, and small pores were the main positions of EIOR. Water film was formed in large pores, which increases the migration resistance of the liquid, and allowed gravity to play an obvious role. Finally, based on the modified Aronofsky index model, an EIOR model suitable for the Changqing Chang 7 reservoir was proposed, which achieved a better match between actual production and simulated production of horizontal wells. • NSI fluid has ability of wetting modification and reducing interfacial tension, and shows good effect of EIOR. • Field fracturing parameters of NSI fluid are optimized, and its production is more than 4 times higher than conventional fluid. • Driving force of EIOR in small pores is dominated by capillary force and gravity also benefits imbibition in large pores. • An Aronofsky EIOR model is established, which is suitable for Chang 7 reservoir. [ABSTRACT FROM AUTHOR]