Imbibition Rate Research Articles

Capillary infiltration measurements by finite size drop method: wetting, spreading and infiltration of liquid silver in porous iron

The study proposes a direct method for studying capillary infiltration of porous media using high-speed measurements of the shape of an imbibited droplet of finite size. The method assumes isotropic infiltration, and the change in the droplet volume on the surface is equated to the volume of imbibited liquid. The shape of the imbibited volume in the case of a droplet of finite volume is assumed to be a flattened spheroid. In the mathematical model, the rate of change of the apparent volume obtained in the experiment is reduced to the rate of movement of the liquid front in the porous media.Measurements of capillary processes in the silver (melt)-iron (porous or dense solid) system were carried out at various temperatures in a vacuum of 10-3Pa to verify the model. Time dependencies of the wetting contact angle and the contact diameter of pure silver melt on the surface of dense solid iron, the imbibition rate of silver melt into porous iron, and the kinetics of sintering of iron powder were measured. All measurements were conducted using direct methods of high-speed video and thermal imaging. As a result, in addition to the application of the proposed imbibition model, kinetic dependencies of the mentioned processes at various temperatures in the range from 1000 to 1150 °C were obtained and their activation energies were determined.

Experimental study of supercritical CO2-H2O-coal interactions and the effect on coal spontaneous imbibition characteristics

The interaction among supercritical CO2 (ScCO2)–H2O-coal can impact the pore structure of coal, thereby bringing about changes in the spontaneous imbibition (SI) characteristics of coal. This is of great significance for the effect of hydraulic fracturing and the increase in coalbed methane production. The changes in pore structure and imbibition characteristics of coals with different degrees of metamorphism after ScCO2-H2O treatment were studied using nuclear magnetic resonance technology. The experimental results indicate that ScCO2-H2O treatment can increase porosity, enhance pore connectivity, and significantly increase the imbibition rate. It also alters the proportion of different pores. The proportion of micropores, microfractures and fractures increases, while the proportion of small pores, mesopores and large pores decreases. This change is more significant in low-rank coal. During SI, the main contribution to the imbibition volume of coal samples is consistent with the proportion of pore structure; hence, there are differences in the extent of changes in the SI characteristics between low-rank and high-rank coals. The numerous etched pores produced by ScCO2-H2O treatment exhibit self-similarity, reducing the roughness and complexity of the pores while enhancing connectivity. The emergence of a large number of microfractures and fractures has a minor impact on the change in SI volume and rate but affects the mode of SI.

Controlling parameters of co-current and counter-current imbibition in naturally fractured reservoirs

Naturally fractured formations are complex petroleum reservoirs that are poor candidates for waterflooding due to difficulties in controlling sweep. Injected water can readily propagate through the fracture system, bypassing the hydrocarbon stored in the matrix. Instead, such systems rely on spontaneous imbibition (SI) from the matrix into the extensive fracture gathering system. SI is a crucial recovery mechanism that relies on capillary pressure-dominated fluid movement. SI can occur through two modes, co-current (COSI) and counter-current (COUSI), depending on the relative direction of fluid movement in response to prevailing boundary conditions. Analytical solutions that incorporate the diffusivity coefficient, which combines relative permeability and capillary pressure curves, are used to describe co-current and counter-current imbibition mechanisms. The perturbation method is one approach in solving these analytical equations. In-situ water saturation profiles, ascertained through experimental CT scanning, serve as validation benchmarks for both co-current and counter-current models. The understanding of the SI process can give more details about the fracture-matrix interactions and the exchange function. Sensitivity studies with respect to the parameterization of the driving force for imbibition, capillary pressure, and the resistive forces, captured in relative permeability curves, can guide experimental study planning and aid in inverse problem analysis in the characterization of naturally fractured reservoirs. The results of a parametric study show that capillary pressure curve parameters, such as capillary entry pressure and capillary exponent, significantly affect the position of the waterfront which indicates the imbibition rate. In addition, the water relative permeability exponent has greater impact on both shape and position of water profile than other relative permeability parameters. The nonwetting phase parameters, like oil endpoint relative permeability and oil exponent, have the least influence on water saturation profile.

Spontaneous imbibition of unsaturated sandstone under different vertical temperature gradients: neutron radiography experiments and dynamic models

To elucidate the imbibition behavior of water in complex temperature and stress environments, spontaneous imbibition experiments were conducted on unsaturated matrix sandstones at different vertical temperature gradients by neutron radiography technology. Additionally, corresponding dynamic models of water imbibition in porous media were established. The research results reveal the phased characteristics of sandstone spontaneous imbibition and the influence of vertical temperature gradient on the evolution of wetting front. Specifically, the initial development speed of the wetting front increases with an increase in the vertical temperature gradient, indicating a direct relationship. However, the growth rate of the wetting front gradually slows down with increasing time, eventually reaching a saturated state. Model validation demonstrates that the traditional Washburn's law is still valid in isothermal conditions without temperature gradient (G=0). Further analysis indicates that the imbibition rate has a direct correlation with linear thermal expansion coefficient (α) and viscosity temperature coefficient (β) across various vertical temperature gradients, and an inverse correlation with surface tension temperature coefficient (γ). Furthermore, when the values of α, β, and γ fall below 0.001, their impact on the imbibition rate becomes negligible. The sensitivity of the imbibition rate to parameters γ, β, and α decreases in that order, with γ being the most sensitive, followed by β, and α being the least sensitive. Moreover, the relative importance of α, β, and γ dictates their specific influence on the imbibition rate, and a synergistic effect exists among these parameters, which collectively influence the water absorption behavior of sandstone.

Evaluation of Post-fracturing Imbibition Oil Displacement Efficiency in Shale Reservoirs

In order to clarify the imbibition law of shale oil after fracturing with guanidine gum and nano-slickwater, this study quantitatively analyzed the imbibition efficiency of shale core under different time periods of two kinds of fracturing fluids through the imbibition experiment of natural shale core and nuclear magnetic resonance test technology, and preliminarily understood the microscopic crude oil production characteristics of pore throat of shale imbibition. The experimental results show that the imbibition oil removal efficiency of nano-slick water reaches 34.7 %, which is higher than that of guanidine gum fracturing fluid. In the high imbibition efficiency stage of rock samples, within 6 h of the beginning of the experiment, the small pore porosity reaches 20.8 %, the large pore and fracture reach 30 %, and the final imbibition oil displacement rate can reach 31.7% and 39.6 %. The development of micro-fractures and bedding fractures is beneficial to improve the imbibition efficiency. With the extension of time, the imbibition rate gradually decreases, and the utilization degree of pore throat is limited.

Effect of Cold Plasma Treatment on Seed Quality Parameters under Cold Stress in Rice (Oryza sativa L.)

Abiotic stresses impinge rice production all over the world. Low temperature stress is one among the major abiotic stresses in crop plants significantly affecting plant growth, survival, reproduction, and dispersal. Therefore an experiment was carried out on rice variety BPT 5204 to study the effects of cold plasma treatment under cold stress. Attempt was made to standardize appropriate stage of exposure (dry seeds, sprouted seeds), voltage (30kv, 20kv) and duration of exposure (10min, 20min) based on the performance in vigour tests i.e., germination, seedling dry weight, seedling vigour index-II, field emergence test, abnormality and imbibition tests at a temperature of 18°C. Results indicated that exposure of sprouts of BPT 5204 at 20kv for 20min has given highest germination (88%), seedling dry weight (68.10 mg), seedling vigour index II (597), field emergence (77%), imbibition rate (0.495) and lowest abnormality (12%) in comparison to control and other treatments. This indicates that cold plasma treated at 20kv for 20min on paddy sprouts had a greater stimulatory effect on plant growth and development under cold temperature conditions.

Water wicking in phosphorene-based nanochannels: Effect of surface texture

The imbibition dynamics of water in a nanochannel made of two-dimensional phosphorene are explored using Molecular Dynamics. The partial wetting behavior of water nanodroplets on phosphorene sheets is examined first. The initial spreading of the wetted area (A) and internal energy (ΔE) are found to follow the power law, A ∼ t1/2 and ΔE-t1/2. Additionally, the Laplace pressure and equilibrium contact angle, determined from water plugs confined within nanoslits, verify the applicability of the Young-Laplace equation at the nanoscale. For water wicking in channels with a width of N layers of phosphorene sheets, the rate of change of both the penetration length and internal energy is proportional to t1/2. However, the imbibition rate in narrow nanoslits (N = 2 ∼ 5) depends on the orientation (armchair and zigzag) of the walls. This effect gradually diminishes as N increases. It was observed that, except for N = 1, the imbibition rate decreases with increasing channel width, which contradicts the prediction of Lucas-Washburn equation. Compared to smooth graphene-based channels, the imbibition rate is lower in phosphorene-based channels. Nonetheless, this difference decreases as the channel width increases, suggesting that the impact of surface roughness becomes less pronounced with larger channel widths.

Quantification of seepage characteristics in shale oil reservoirs: A triple medium model-driven approach

Shale oil is an important unconventional oil and gas resource depicting a complex microstructure with various pore types and fluid distribution. In particular, the fluid flow mechanism and the associated percolation characterization theory have recently gained notable interest. Here we establish a mathematical model to describe non-wetting and wetting phase imbibition in shale oil formation. The model is based on the triple continuum medium theory taking into account the wetting characteristics of the shale/oil/brine system, the percolation processes in inorganic and organic pores, and the dynamic process of adsorption and absorption of crude oil in kerogen. The experimental results of oil and water imbibition were fitted thereby obtaining seepage physical parameters and validating the realiability of the proposed model. The impact of physical properties (e.g. inorganic and organic permeability, equivalent cross-flow coefficient, and diffusion coefficient) on the dynamic characteristics of the imbibition process was also evaluated. The results show that the inorganic permeability is between 10−7–10−4μm2 and the organic permeability is between 10−10–10−6μm2. The imbibition rate demonstrates a positive correlation with inorganic and organic permeability, equivalent cross-flow coefficient, and diffusion coefficient. The larger the difference between inorganic and organic permeability, the more pronounced the “bi-horizontal segment” feature of the shale oil imbibition saturation curve. The proposed model effectively calculates the reserves in both organic and inorganic pores, thereby addressing the time-consuming challenges associated with experimentally obtaining seepage parameters. This study thus provides a theoretical basis for precisely evaluating fluid flow in shale oil reservoirs.

Enhancement of capillary flow via precursor film thickening in graphene nanochannels

The wicking dynamics of total wetting liquids in a nanocapillary differ from those of partial wetting liquids due to the presence of the precursor film. In this work, the wetting behavior of total wetting liquids (isopropyl alcohol and dimethylformamide) on graphene sheets, as well as the imbibition dynamics in graphene-based nanoslits, are investigated using molecular dynamics. The spontaneous spreading dynamics can be described by two power laws, with the long-term behavior conforming to the viscosity-dominated Tanner’s law. The imbibition behavior within nanoslits shows a deviation from Washburn’s equation, displaying a unique two-stage pattern. This pattern is marked by a turning point that is related to the type of liquid and is independent of the channel width. Notably, the imbibition rate in the second stage exceeds that in the first. The advancing rate of the precursor film is insensitive to changes in channel width. After the precursor film reaches the end of the channel, the second stage commences, followed by the re-thickening of the film. This re-thickening reduces the curvature radius of the meniscus and increases the driving Laplace pressure, thereby enhancing the capillary flow in the second stage.

Capillary flow in nanoporous media: effective Laplace pressure

Imbibition dynamics in nanoporous media are explored using many-body dissipative particle dynamics for three types of nanoporous structures with varying porosities (ε), including random networks, periodic networks, and random voids. The permeability (ĸ) of the nanoporous structure is systematically determined through steady flow based on Darcy’s law. The imbibition simulation outcomes align with the experimental results, demonstrating that the square of the penetration length (L2) is linearly proportional to time (t), L2 = (S1)t. The degree of imbibition rate, represented by S1, is observed to increase with ε but remains insensitive to the pore structure, indicating the predominant role of viscous resistance over wettability-driven imbibition. The effective Laplace pressure, calculated from S1, is used to estimate the effective pore diameter based on the Young-Laplace equation. The resultant diameter is considerably larger than the actual pore size. This finding implies that the driving force for imbibition in porous media is substantially weaker than it is in a capillary.

Experimental Study of Forced Imbibition in Tight Reservoirs Based on Nuclear Magnetic Resonance under High-Pressure Conditions

This study utilizes nuclear magnetic resonance (NMR) techniques to monitor complex microstructures and fluid transport, systematically examining fluid distribution and migration during pressure imbibition. The results indicate that increased applied pressure primarily affects micropores and small pores during the initial imbibition stage, enhancing the overall imbibition rate and oil recovery. Higher capillary pressure in the pores strengthens the imbibition ability, with water initially displacing oil from smaller pores. Natural microfractures allow water to preferentially enter and displace oil, thereby reducing oil recovery from these pores. Additionally, clay minerals may induce fracture expansion, facilitating oil flow into the expanding space. This study provides new insights into fluid distribution and migration during pressure imbibition, offering implications for improved oil production in tight reservoirs.

BIOESTIMULANTE Y TIEMPOS DE IMBIBICIÓN SOBRE LA GERMINACIÓN DE SEMILLAS DE MARACUYÁ (Passiflora edulis S., Passifloraceae

<p><strong>Background: </strong>Passion fruit (<em>Passiflora edulis</em> S.) is a tropical fruit of socio-economic interest in Peru, used as an ingredient in the food industry, esthetics and medicine. However, this crop has a low germination power, so it is necessary to carry out pre-germination treatments to increase the germination percentage and the initial development of the seedlings. <strong>Objective:</strong> to evaluate the effect of different biostimulants at 12 h and 24 h of hydration on passion fruit seed germination. <strong>Methodology: </strong>passion fruit seeds of large and round fruits, free of pathogens, were collected. The aryl-free seeds were treated: T0 (distilled water), T1 (sulfur 25 g/10 L), T2 (sulfur 50 g/10 L), T3 (biol 3%), T4 (biol 5%), T5 (cinnamon 25%), T6 (cinnamon 50%), T7 (buttermilk 25%) and T8 (buttermilk 50%) for 12 h and 24 h imbibition. The variables evaluated were: water absorbed, imbibition rate (IR), germination percentage (GP), germination speed (GS), germination index (GI), first day of germination (FDG). <strong>Results:</strong> The highest water absorption occurred in the first 9 hours. Treatments T4, T5 and T6 significantly improved the GP, GS, GI, FDG at 12 h imbibition. However, at 24 h imbibition these values decreased. GP presented a high positive correlation with GS and GI. Likewise, GS presented a high negative correlation with FDG. <strong>Implications: </strong>The use of biostimulants increases germination. <strong>Conclusions:</strong> Cinnamon extract at 25% and 50%, and biol 5% at 12 h of imbibition have significantly improved the variables evaluated compared to imbibition at 24 h. The positive correlation between the variables indicates a direct relationship between them.</p>

Germination of <I>Cassia fistula</I> L. Seeds by Mechanical Stress

The effect of mechanical stress in presence of different kinds of chemical media on seed germination, percentage of germination and rate of imbibition in seeds of Cassia fistula L. have been studied. A unique germination percentage of seedlings free-from fungus attack were observed in cracked and punctured seeds. Modifications raised by this stress in seeds enhances quick germination in presence of suitable moisture media. To make comparative study between the rate of imbibition and percentage of germination and to know the susceptibility of seeds towards fungal attack, heating and roasting in addition to cracking and puncturing, were applied and discussed.

Effective techniques to break seed dormancy in Rhodomyrtus tomentosa (Aiton) Hassk. for seed germination enhancement

Rhodomyrtus tomentosa is a valuable plant for medical and pharmaceutical uses. The plant reproduces through seeds; however, the seeds become dormant, resulting in low germination rates. The industrial demand for this plant is expanding, making sustainable propagation a major challenge. The present study aims to evaluate different techniques for breaking the dormancy of R. tomentosa seeds. A randomized design was used to evaluate different techniques for breaking the dormancy of R. tomentosa seeds, including de-operculum, chemical scarifications, and exogenous gibberellic acid (GA3), in both laboratory conditions at ambient temperature (25 ± 2 °C) and field conditions. The characteristics of R. tomentosa fruit and seeds were assessed. The average mass, width, and length of fruits were 1.90 g, 13.78 g, and 15.27 g, respectively. The average seed/ripe fruit contained 57 seeds, and the mass of 1000 seeds was 2.64 g. Seed viability (100 %) was achieved in the treatment with 0.075 % tetrazolium at 45 °C for 3 h, but a germinated seed was only 13.00 %. The study of breaking seed dormancy in laboratory conditions revealed that de-operculum significantly enhanced seed germination up to 83.00 % within 15 days, compared with control treatment of 13.00 % within 34 days (p ≤ 0.01). In contrast, 10 % KNO3 for 24 h under field conditions resulted in the highest seed germination rate of 91.00 % within 34 days, while de-operculum treatment showed 63.00 % of seed germination within 15 days. In addition, the seed water imbibition rate between control and de-operculum seeds was evaluated. The results demonstrated that the control seeds absorbed water more slowly than the de-operculum seeds, indicating that de-operculum promoted faster germination. The findings concluded that breaking seed dormancy is important for R. tomentosa seed germination. De-operculum and KNO3 were discovered to be effective ways of breaking seed dormancy in R. tomentosa.

Effect of initial water saturation and water film on imbibition behavior in tight reservoirs using nuclear magnetic resonance technique

Initial water saturation has a significant influence on spontaneous imbibition, and it impacts the imbibition rate and imbibed liquid dynamic distribution among pore networks. At present, the effect of initial water saturation on spontaneous imbibition is still unclear, especially the water film effect caused by initial water saturation varies during imbibition. To address these issues, we prepared the samples with varied initial water saturation through vapor adsorption and then conducted spontaneous imbibitions on these samples, which were monitored by nuclear magnetic resonance (NMR). Samples were selected from tight sandstone reservoirs in the eastern Ordos Basin. From the NMR spectrum corresponding to different imbibition duration, the left wing of the left peak at the initial water saturation is usually higher than the ones after imbibition, mainly caused by the water film effect. When the water film on the surface of large pores is too thin, it is prone to be interpreted as water in small pores because the water film has a quick relaxation time than the water in the center part of pores. The water film effect disappears when the whole pores are filled with water, and the inversed small pores decrease. The relaxation time of the water film is shorter than 0.51 ms in the tested samples. This study is conducive to understanding the effect of initial water saturation on liquid dynamic distribution during imbibition, especially the water film effect variation during imbibition and the T2 value of the water film.

Study on the Flow Behavior of Gas and Water in Fractured Tight Gas Reservoirs Considering Matrix Imbibition Using the Digital Core Method

Tight gas reservoirs possess unique pore structures and fluid flow mechanisms. Delving into the flow and imbibition mechanisms of water in fractured tight gas reservoirs is crucial for understanding and enhancing the development efficiency of such reservoirs. The flow of water in fractured tight gas reservoirs encompasses the flow within fractures and the imbibition flow within the matrix. However, conventional methods typically separate these two types of flow for study, failing to accurately reflect the true flow characteristics of water. In this study, micro-CT imaging techniques were utilized to evaluate the impact of matrix absorption and to examine water movement in fractured tight gas deposits. Water flooding experiments were conducted on tight sandstone cores with different fracture morphologies. Micro-CT scanning was performed on the cores after water injection and subsequent static conditions, simulating the process of water displacement gas in fractures and the displacement of gas in matrix pores by water through imbibition under reservoir conditions. Changes in gas–water distribution within fractures were observed, and the impact of fracture morphology on water displacement recovery was analyzed. Additionally, the recovery rates of fractures and matrix imbibition at different displacement stages were studied, along with the depth of water infiltration into the matrix along fracture walls. The insights gained from this investigation enhance our comprehension of the dynamics of fluid movement within tight gas deposits, laying a scientific foundation for crafting targeted development plans and boosting operational efficiency in such environments.

Exploring the effects of non-thermal plasma pre-treatment on coriander (Coriander sativum L.) seed germination efficiency

This study investigates the effects of non-thermal plasma (NTP) treatment on the germination characteristics of coriander seeds (Coriandrum sativum L.). Different germination factors, water imbibition rate and changes in mass, were analyzed. The results indicate that a suitable duration of NTP treatment (180 s and 300 s) enhances seed germination characteristics, whereas prolonged exposure (420 s) leads to adverse effects. Furthermore, shorter NTP exposures (180 s) improved water absorption and surface properties of seeds, while longer exposures (420 s) caused mass loss and compromised seed vigor. Overall, the findings demonstrate the significance of optimizing NTP treatment conditions for enhancing seed germination characteristics.

Effect of lignin in cellulose nanofibers on biodegradation and seed germination

AbstractPure cellulose nanofibers (CNFs) rapidly degrade in soil, limiting their prospective applications in agriculture. We incorporated lignin into CNFs as an antimicrobial and crosslinking agent to control the biodegradation rate. CNFs with different lignin concentrations were prepared by mechanochemical treatment in the presence of choline chloride-urea deep eutectic solvent. These were characterized using conductometric titration, scanning electron microscopy, and FT-IR. The fibers were applied to soil to determine the effect of lignin on soil respiration and nanocellulose degradation, and were used as a substrate for radish and cress seed germination. Modifying the lignin content of the fibers successfully modulated the biodegradation rate in soil. Fibers containing 35% lignin degraded 5.7% in 14 days, while fibers with 20% lignin degraded 20.8% in 14 days. Nanofiber suspensions showed low chemical inhibition for the germination of radish and cress seeds but higher lignin contents reduced the imbibition rate as a seed coating. This study presents the first use of lignin to control the biodegradation rate of cellulose nanofibers in a one-pot, scalable and sustainable system, allowing the advancement of lignocellulose nanofibers for applications such as seed coatings, mulches, and controlled release fertilizers. Graphical Abstract

Investigating the Influencing Factors of Imbibition of Fracturing Fluids in Tight Reservoirs

Tight reservoirs are the focus of unconventional oil and gas resource development, but most tight reservoirs exhibit complex pore structures, strong non-homogeneity, and limited water drive development. Fracturing fluid imbibition is a critically important way to improve the recovery of tight reservoirs. In this paper, an NMR experimental device was used to conduct imbibition experiments in tight reservoirs, and the relationship between temperature, pressure, matrix permeability, and imbibition recovery was investigated. Based on the fracturing fluid imbibition recovery curve, the imbibition process is divided into the fast imbibition stage, slow imbibition stage, and imbibition equilibrium. In addition, based on the pore structure division, the recovery changes of each pore under different experimental conditions were quantitatively analyzed. The results indicate that the highest imbibition recovery is achieved at an experimental pressure of 5 MPa within the range of 0 MPa to 15 MPa. Increasing the experimental pressure can increase the imbibition rate but will not increase imbibition recovery. Within the investigated range in this paper, fracturing fluid imbibition increases with rising temperature and matrix permeability. Moreover, the recovery of each pore gradually increases with the experimental pressure ranging from 0 MPa to 5 MPa. The recovery of each pore is positively correlated with matrix permeability and temperature. During the experiment, micropores contributed the most to the recovery, while macropores contributed the least. The study in this paper guides the efficient development of tight reservoirs.

Three-dimensional modeling of nanoconfined multiphase flow in clay nanopores using FIB-SEM images of shale

<p>Understanding the flow characteristics within shale nanopores is crucial for enhancing hydrocarbon recovery. However, the flow characteristics of wetting and non-wetting fluids on nanopore surfaces differ significantly, limiting the accurate prediction of hydrocarbon accumulation and migration. This work introduces the Euler-Euler volume of fluid method to establish a multiphase flow numerical model in shale nanopores, considering complex pore topology, slip flow, and capillary effects. Based on natural three-dimensional shale nanoporous systems constructed from FIB-SEM images, single-phase water/oil flow and water-oil forced imbibition simulations are carried out under the complete wetting condition. Results show that the displacement pressure is reduced and the imbibition rate is elevated considering nanoscale slip effects. As imbibition progresses, the pressure and imbibition rate gradually converge toward the values observed in conventional flows. In complete wetting nanoporous systems, water flow experiences high pressure and low velocity, whereas the pressure for oil flow is significantly reduced. Forced imbibition may undergo a transition from capillary force-dominated to viscous force-dominated, with a negative displacement pressure at the initial stage. Furthermore, the fluctuations in water-oil mass flow considering the slip effect are less pronounced than those observed in conventional flows, leading to reduced residual fluid saturation in blind-end pores and pore bodies caused by snap-off events. Pore systems with poor connectivity and narrow throat structures correspond to low displacement efficiency. The findings of this work explain the impact of nanoscale slip effects on flow characteristics in unconventional reservoirs, contributing to the reasonable assessment of fluid flow capacity and facilitating production planning.</p>