Imbibition Research Articles

Field electron emission enhanced streamer cold plasma interaction on seed surface wettability

Hybrid streamer cold plasma (HSCP) can be used in nanoscale surface modification, especially for curved biological surfaces. Here, the HSCP was applied to a rice (Oryza sativa L.) seed under different gas ambient and electric field distributions. Seed wettability enhancement (water imbibition (WI) and apparent contact angle (ACA)) is the primary method used to understand the dynamic of plasma interaction on biological surfaces. The extremely non-uniform electric field is directly responsible for plasma generation, via fringe field enhanced electron emission, which consequently impacts the ionization process. Further, this process is indirectly related to the plasma-enhanced electrochemical and physical reactions on biological nanoscale surface etching and functionalization. Despite being generated by means of different plasma mechanisms, the water imbibition time (WItime) on the top and bottom (shadow) of treated seed surfaces show similar characteristics, namely exponentially fast decay right after treatment, and a consequent linear decrease until reaching the saturation level. The stronger the corona discharge plasma, the less the difference in surface functionalization between the top and bottom surfaces. We demonstrate the model of WItime enhancement as a function of treatment time based on fringe field enhanced electron emission mediated impact ionization and reactive species (RS) generation for surface transformation.

The increased viscosity effect for fracturing fluid imbibition in shale

Understanding water imbibition behaviors in shale formations plays an essential role in shale gas development. The effective viscosity of water in shale nanopores is usually different from that of the bulk phase because of confined conditions. In this work, a model considering interactions between water and a solid surface is proposed to predict the effective viscosity of water at the nanoscale, which is inserted into the classic Lucas-Washburn (L-W) model to describe the water imbibition behavior in shale formations. This model is derived based on a molecular kinetic theory and incorporates the disjoining pressure. Published experimental data is used to validate the model. It is demonstrated that the effective viscosity of water in hydrophilic nanopores is much higher than that of the bulk phase because of strong interactions between water and a solid surface, and the deviation significantly increases when the separation is below 10 nm. For a hydrophilic capillary tube with a diameter of 10 nm, the water effective viscosity is approximately 2.5 times higher than that of the bulk phase. Moreover, this deviation is larger for a capillary tube compared with a capillary channel, because of the curvature effect. Besides, the effective viscosity for water under a hydrophobic condition is smaller than that of the bulk phase water, because the structural repulsive force dominates under a hydrophobic condition. This work establishes a theoretical foundation to calculate the effective viscosity for water flow at the nanoscale. Furthermore, it helps to understand fracturing fluid imbibition behavior in shale gas reservoirs, which will benefit the simulation of fluid flow at the reservoir scale.

Investigation on water phase trapping mechanisms in tight gas reservoirs: Pore-scale visualization observation and core-scale flooding analysis

Water phase trapping (WPT) is one of severe formation damage issues for the safe production in tight gas reservoirs. In this work, both pore-scale and core-scale investigation of the formation process of WPT were performed. Real-time observation of the water invasion and formation of trapped gas was achieved using visualized micromodel. Meanwhile, core flooding experiments including water imbibition and drainage experiments were conducted to analyze the responses of gas permeability and water saturation changes to the formation of WPT. The micromodel visualization experiments presented an intuitive gas-water two-phase flow scenarios which revealed the microscopic mechanisms of the WPT vividly. It pointed out that snap-off and circumfluous flow are the two major mechanisms to break the bulk gas flow and generate the trapped gas during WPT formation. The results of core flooding provided a causality link between the changes of gas permeability and water saturation, which showed a macroscopic consequence to the gas flow ability caused by WPT damage. These findings will benefit a better understanding of the formation process and damage mechanisms of WPT.

Physiological potential of chickpea seeds

The chickpea crop is grown predominantly in the arid and semi-arid regions of the world. India is the largest producing country, in Brazil production is scarce, leading the country to import almost all of what is consumed. Grains are a good source of carbohydrates, proteins and even essential amino acids. One of the first steps towards profitable production is knowledge about the availability of high-quality seeds. The germination test, evaluates the formation of normal seedlings in ideal conditions, so it must be associated with vigor tests, rapid and uniform germination of the seeds, simulating adversities in the field. Among the tests used, accelerated aging and electrical conductivity are common, as well as the study of the water absorption curve by the seeds. Accelerated aging is based on high temperature and humidity, real stress conditions in the field or in storage. For chickpeas, it is recommended to use saturated saline solution, 24 h exposure, at 41 ºC and evaluation at the first count. The electrical conductivity is determined by the amount of leachate, the higher the values, the less vigor. The most suitable methodology is the use of 75 seeds, volume of 100 mL of water, during 30 h of soaking. The process of water imbibition by the seeds occurs according to a three-phase pattern. In studies with the species, there was no clear definition between the three phases. However, the Peleg model adjusted to the imbibition data of the analyzed cultivars. There are other efficient ways, not yet described, for evaluating the physiological potential in this species, among them the tetrazolium test, images from scanners and radiographs, or even magnetic resonance of seeds. Although these tools require expensive equipment, they can streamline and increase the accuracy of seed analysis.

Dispersal and germination of winged seeds of Brandisia hancei, a shrub in karst regions of China

Brandisia hancei (Paulowniaceae) is a widely distributed shrub in karst regions in southwestern China. Its seeds have a membranous wing, and they mature just before the rainy season begins. To assess the effect of the wing on seed dispersal and germination of B. hancei, we measured the dispersal distance at varying wind speeds and release heights, falling duration from different release heights, floating duration on still water, rates of imbibition of water, and drying and soil adherence to seeds. Germination experiments were conducted on intact and de-winged seeds immediately after harvest. The wing increased the falling duration in still air and the floating ability on water. Dispersal distance of winged and de-winged seeds did not differ at a wind speed of 2.8 m s−1, but at 3.6 and 4.0 m s−1 dispersal distances were greater for de-winged than for winged seeds. Seed wing had little effect of absorption and retention of water, but significantly increased soil adherence to the seeds. Mature seeds were non-dormant and germinated to over 90% with a mean germination time of about 10 days. By combining the environmental conditions in karst habitat with the seed traits of B. hancei, we conclude that dispersal and germination of winged seeds are adapted to the precipitation seasonality in heterogeneous habitats absence of soil.

Core-scale modeling of surfactant-assisted spontaneous water imbibition in carbonates

This work numerically investigates surfactant effects on spontaneous water imbibition in oil-wet carbonates. An open boundary core-scale imbibition model with 9 × 9 × 10 gridblocks was used in UTCHEM to simulate carbonate core plug exposure to a vast water body. The simulation models were developed based on surfactant-assisted imbibition tests that were conducted in secondary and tertiary oil production modes using Amott cells at 75°C. Capillary and gravity forces were captured by history matching the experiments. Through history matching, the inputs for surfactant adsorption and diffusion, capillary pressure and relative permeability were calibrated. In tertiary mode, the surfactants-assisted imbibition process presents the performance in mixed-wet state rather than oil-wet state, which is governed by wettability alteration. A simulation model for surfactant-assisted imbibition in secondary mode was used to investigate the effects of various factors including interfacial tension (IFT) reduction, wettability alteration, adsorption, volume of surrounding water and capillary force. The simulation results suggest that surfactant-assisted water imbibition in secondary mode is gravity dominant, which is facilitated by both IFT reduction and wettability alteration caused by addition of proper surfactants. Different from water imbibition in water-wet core, it presents vertically dominant oil flow with a hemispherical oil-rich area and uneven remaining oil saturation. It is obvious that sufficient surfactant supply in vast water is required to make effective imbibition, in consideration of surfactant consumption and changes in concentration gradients. This core-scale modeling provides insights of surfactant-assisted imbibition in initially oil-wet carbonates and helps scale up the application in a cost-effective way.

Concrete shrinkage and creep under drying/wetting cycles

Concrete shrinkage and creep under variable hydric conditions are important factors for the safety and durability of concrete especially in nuclear reactor or nuclear waste storage background. A large (and long – more than 900 days) experimental campaign, conducted on two different concretes, has therefore been designed to study the strains of non loaded and loaded concretes submitted to drying and liquid water imbibition cycles. For the purposes of comparison, concrete strains and mass variations during drying only (50% RH) and/or following cycles of drying/rewetting were also recorded. This allowed the identification of desiccation shrinkage, basic creep and drying creep at 10 MPa of axial stress. Important results were found and have shown that the final mass and strain are not deeply modified by the introduction of a rewetting phase either for a loaded or a non loaded material.

Mathematical model of the spontaneous imbibition of water into oil-saturated fractured porous media with gravity

Studying the mechanism of spontaneous imbibition into oil-saturated fractures is of great significance for unconventional oil reservoir development. Both theory and experimental observations indicate that SI in fractures is significantly different from that in tight matrix. In this work, the implicit analytical solution of the spontaneous water imbibition into a single oil-saturated fracture with gravity is first proposed. The results show that the difference in imbibition velocity with and without gravity increases with the increase in fracture aperture. There is a critical fracture length for SI in the single oil-saturated fracture. Based on the fractal/normal distribution of fracture apertures, the core-scale mathematical model of spontaneous imbibition in the oil-saturated fractured porous media is proposed. The effect of fracture distribution on the oil imbibition rate is investigated and discussed.

A methodology for chemical formulation for wettability alteration induced water imbibition in carbonate reservoirs

Oil recovery tests are performed to evaluate the performance of different single and mixed-surfactant systems. Contact angle and O/W IFT measurements are first used to derive the capillary driving forces necessary for spontaneous imbibition. Surfactant mediated imbibition in oil-wet Indiana limestone cores resulted in additional oil recoveries over brine and the extent of oil recovery was determined by the surfactant type, initial water saturation, and brine salinity. A maximum oil recovery of 47% at 50 °C was observed for the best single surfactant system while a maximum oil recovery of 27% at 90 °C was observed for the best mixed surfactant system. It was found that the highest oil recovery occurs at intermediate water saturations. The positive effect of SO42− ions on wettability alteration is also noted with an approximately 10% incremental oil recovery observed at 1% sulfate concentration. Universal recovery curves corresponding to gravity-driven imbibition process are obtained. To obtain predictive tools for oil recovery, the ultimate oil recoveries are scaled with the capillary pressure to generate a universal oil recovery curve as a function of the cloud point temperature difference as a thermodynamic descriptor.

Enhancing the seed germination process of Montezuma cypress (Taxodium mucronatum Ten.)

ABSTRACT Montezuma cypress (Taxodium. mucronatum) is an ecological, cultural and economically valuable riparian tree species. Two experiments evaluating the effectiveness of various seed treatments were conducted to identify germination best practices and to evaluate the dynamics of the germination process. Seeds were collected on two occasions, one year apart, from the only remaining natural T. mucronatum tree stand in the United States. The seeds were subjected to various soaking and stratification conditions. Across all treatments, germinability ranged between approximately 30%-40%, with slightly higher values occurring among the second seed cohort. Overall, no significant differences in germinability were detected in either study, however, soaking seeds in water for 96 hours and stratifying them in moist conditions for 3 weeks significantly accelerated the germination process. Seeds soaked briefly in a NaOH solution followed by a 48-hour water soak demonstrated more synchronous germination than other treatments. Control conditions in which seeds were not soaked or stratified exhibited the slowest germination. These findings are consistent with previous evidence showing that T. mucronatum seeds do not exhibit physiological dormancy and that treatments promoting seed water imbibition enhance the germination process. This study adds to the limited available research on T. mucronatum propagation practices and offers novel data on the germination parameters of seeds sourced from a natural U.S. stand, rather than seeds from few scattered individual trees, as in previous reports. Seed germination recommendations garnered from this study can improve nursery production of T. mucronatum to enhance ecological restoration efforts and ornamental production.

Experimental Investigation of Spontaneous Water Imbibition into Methane-Saturated Shales under Different Methane Pressures

Spontaneous imbibition of hydraulic fracturing fluids is an important mechanism for the development of shale gas reservoirs. Spontaneous imbibition experiments have been widely performed under stan...

Effect of bio-stabilizers on capillary absorption and water vapour transfer into raw earth

While raw earth can be used as a structural material, its water sensitivity limits its use in modern construction. Earth has a strong affinity with water. Both water imbibition and water vapour transfer have to be taken into consideration. This affinity can be a positive point to regulate indoor ambience, but it can also negatively affect earth’s mechanical properties. To avoid this possible detrimental effect, bio-based additions are used all around the world to stabilize, protect from water and enhance the mechanical properties of earth-based building materials. Bio-based stabilizers have to limit liquid water absorption and maintain mechanical properties without acting as a water vapour barrier that can lead to durability issues. In this article, capillary water absorption and water vapour permeability measurements are performed for combinations of various earths and bio-based additions (linseed oil, xanthan gum, casein, alginate and tannins). Linseed oil and xanthan gum help to protect the earth-based samples from absorbing liquid water without affecting the water vapour transfer in these materials.

Spontaneous Capillary Imbibition of Water and Nonaqueous Liquids into Dry Quarry Limestones

Rates of spontaneous imbibition of water and nonaqueous liquids into dry limestones have been measured at 25 °C. Thirteen English and French limestones were used, with eight liquids (water, decane, dodecane, sec-butanol, iso-propanol, tetrahydrofuran, perfluorodimethylcyclohexane, ethanediol). For the nonaqueous liquids, the measured sorptivity generally scales as (surface-tension/viscosity)^{1/2} (here called F-scaling). Water sorptivities deviate from F-scaling, indicating partial wetting. A wetting coefficient (wetting index) is derived. Data show that there is little difference in the Hirschwald saturation coefficient measured with the different liquids, although there is a large variation between stones. Results suggest that physicochemical alteration of exposed pore surfaces strongly (and unpredictably) influences the capillary absorption of water by limestones.

Cardanol /SiO2 Nanocomposites for Inhibition of Formation Damage by Asphaltene Precipitation/Deposition in Light Crude Oil Reservoirs. Part II: Nanocomposite Evaluation and Coreflooding Test.

This study aims to evaluate the behavior of Cardanol/SiO2 nanocomposites in the inhibition of the asphaltene damage based on the coreflooding test at reservoir conditions. The nanocomposite design was performed in Part I (https://doi.org/10.1021/acs.energyfuels.0c01114), leading to SiO2 nanoparticles functionalized with different mass fractions of cardanol on the surface of 5 (5CSN), 7 (7CSN), and 9% (9CSN). In this part of the study, the nanocomposite/reservoir fluid interactions were evaluated through interfacial tension measurements and nanocomposite/rock surface interactions using water imbibition and contact angle measurements. Results showed that the designed nanocomposite leads to a reduction of interfacial tension of 82.6, 61.7, and 51.4% for 5CSN, 7CSN, and 9CSN regarding silica support (SN). Whereas, the reduction of the Si–OH functional groups from SiO2 nanoparticles due to the increase of the cardanol content affects the effectiveness of the wettability alteration for 7CSN and 9CSN. Nevertheless, when 5CSN is evaluated, the system is altered from an oil-wet to a mixed-wet state. Coreflooding tests at reservoir conditions were performed to evaluate the oil recovery after asphaltene damage, after damage removal and nanofluid injection, and after induction of a second asphaltene damage to check inhibition. Results show that the selected nanocomposites at a dosage of 300 mg·L–1 enhance the oil recovery in comparison with the baseline conditions via the reduction of the interfacial/surface forces at the pore scale and wettability alteration. It is worth to remark that this improvement remains after the second asphaltene damage induction, which proves the high inhibitory capacity of the designed nanocomposite for the asphaltene precipitation/deposition. Also, the use of the nanocomposites favors the oil recovery more than 50% compared to the asphaltene damage scenario.

Mechanistic study to investigate the injection of surfactant assisted smart water in carbonate rocks for enhanced oil recovery: An experimental approach

More than half of the world's discovered oil is held in carbonate reservoirs, most of which are naturally oil-wet fractured reservoirs. Oil Recovery efficiency can be improved noticeably if the rock wettability is changed from an oil-wet to a water-wet state. However, what factors control the wettability alteration are not clearly specified. In this study, a comprehensive mechanistic study is performed using different experimental tools to investigate the effects of active ions, non-active ions, CTAB, and different combinations of ions and CTAB on the sample rock's wettability. The results indicate that using CTAB and a smart water solution, in which the sodium and chloride ions are eliminated and the concentration of sulfate ions is increased, (SW-0NaCl-4SO42− + 1CTAB) reduced the contact angle to 43.58°. The zeta potential value of the oil-wet calcite powder increased from −61.12 to −7.6 mV after treatment with SW-0NaCl-4SO42− + 1CTAB. Moreover, the mean roughness value of oil-wet calcite powder increased from 5.02 to 25.89 nm after treatment with SW-0NaCl-4SO42− + 1CTAB. In fact, sulfate ions are capable of removing the strongly adsorbed carboxylic groups from the surface and changing the wettability of the calcite surface to a more water-wet state. Also, the cationic surfactant monomers tend to ionically react with carboxylic groups and separate them from the calcite surface. Moreover, the removal of sodium and chloride ions also leads to significant changes in the wettability. The imbibition results showed that the change of wettability from an oil-wet to a more water-wet state results in a critical increase in oil recovery efficiency during imbibition of distilled water into the calcite rock slice. High oil recovery efficiency can be obtained by optimizing the smart water solution composition and using a proper concentration of surfactant.

Aerial roots of orchids: the velamen radicum as a porous material for efficient imbibition of water

Aerial roots of orchids are able to absorb atmospheric water (e.g. rain, mist, dew) and to conduct it to the root interior. The water is absorbed by imbibition into a biological porous material, the velamen radicum, which envelops the aerial root and comprises one or two to several layers. The velamen radicum consists of walls of dead cells and shows an intricate structure. In this contribution, the imbibition process was studied in more detail using mathematical principles and by experimental observation of eight orchid species. The process of absorption can be subdivided into two stages. The initial stage is the attachment of a drop to the rough surface. The drop is then imbibed into the layers of the velamen radicum. During imbibition, the contact angle decreases, because the drop remains firmly pinned to the surface. Imbibition times vary widely, due to differences in the porous structure of the considered species. It could, however, be demonstrated that a detailed theoretical study of imbibition for this complex biological material is possible using structural parameters obtained from microscope images. A third aspect which was considered was evaporation out of the velamen radicum. Also here, observations were consistent with modeling results. The velamen radicum, and other tissues involved in water absorption by aerial roots of orchids, represents an intriguing biological material for studying imbibition and flow in porous materials and has probably a high potential for discovering technically interesting features.

All-Time Modeling of Co-Current Spontaneous Water Imbibition Into Gas-Saturated Rocks Using a Novel Transition Time

Abstract Spontaneous imbibition (SI) into a porous medium is an important transport phenomenon in petroleum reservoir engineering. The study of spontaneous water imbibition is critical to predict the production performance in these reservoirs developed by waterflooding, especially in the fractured gas reservoirs with active aquifers. While some studies have been reported to characterize spontaneous water imbibition into gas-saturated rocks, they are either limited or inaccurate due to the fact that the existing models have specific assumptions that cannot be applied in other time intervals. To this end, we proposed a novel transition imbibition time t* and developed an all-time (including both early- and later-time SI) model to match the experimental SI data. Furthermore, we proposed a novel model to estimate capillary pressures at different water saturations and to characterize the water saturation profile in capillary-dominated stage. Comparison with the existing capillary pressure estimation models was performed to test the differences. The results demonstrated that the all-time model could fit the experimental imbibition data of the entire SI process satisfactorily. The new saturation model established in this paper can be well fitted with the water saturation profile measured by the X-ray computer tomography (CT) scanners. The results and findings from this work may be of great significance in many areas related to SI, particularly in the development of naturally fractured gas reservoirs with active aquifers.

Thermogravimetric study of the behaviour of organic and inorganic polymers contained in four dental resin-based composites

The composition of dental resin-based composite (RBC) matrix is partly responsible for many clinical failures in restorations, which may come from dimensional variation or instability in a wet environment. The objective of this study is therefore to evaluate the thermal stability over time of four dental RBC with different matrices. Silicone cylinders were filled with four different materials and then photopolymerized. To simulate ageing in the buccal environment, half of the samples were placed in a dark place at 37°C for 45 days in sealed compartments containing 2 ml of water. All the RBC produced were subjected to thermogravimetric analysis to measure the loss of mass as a function of temperature. Bis-GMA-based resins and Ormocer materials have similar curves before and after soaking in humid atmosphere. The curves of the UDMA resin are different before and after water ageing, meaning that water imbibition has modified the structure of the composite and its degradation. Even if many curves are similar within the same RBC at different polymerization times or at different pre- and post-ageing times, it is rare to observe a common kinetics between two different composites. Our results show good wet stability of polymerized dental RBC according to the manufacturer’s instructions, although the UDMA-based materials show more variation. It therefore seems that Ormocer resin composite with mass placement have ageing properties that can compete with those of conventional composites whereas those incremented on 2 mm layers are more sensitive to the time necessary for polymerization.

Identification of the wheat C3H gene family and expression analysis of candidates associated with seed dormancy and germination

C3H zinc finger transcription factors play important roles in managing various biotic/abiotic stresses in Aarabidopsis, rice, and maize. The functions of these factors in wheat, however, remain largely unclear. We identified 88 TaC3H genes that were divided into four subfamilies in this analysis. Gene structure and conserved domain analyses indicate that most members of the same subfamily have similar structures. A total of 76 paralogous and 48 orthologous pairs were identified and Ka/Ks values were used to analyze replication relationships amongst wheat, rice, and Arabidopsis. Gene ontology (GO) annotation analysis showed that most TaC3H genes possessed molecular functions, while transcriptome results showed that the 88 TaC3H genes responded to water imbibition. Microarray data for 53 TaC3H genes were obtained and heat maps were generated; these results indicate that these genes are expressed in 13 wheat tissues. Subcellular localization prediction analysis indicates that most TaC3H genes are located in the nucleus. Promoter analysis indicates that most TaC3H genes contained cis-elements including ABRE, GARE-motif, and MBS, indicating that these can respond to various biotic/abiotic stresses. Transcriptome data and quantitative real-time PCR analysis of wheat cultivars with contrasting seed dormancy phenotypes show that five genes TaC3H4/-18/-37/-51/-72 were very likely involved in seed dormancy and germination. Exogenous ABA treatment further indicated that these five genes were responsive to ABA, suggesting that there may be a crosstalk between these genes and ABA signaling pathway in controlling seed dormancy and germination. These results provide a theoretical basis for subsequent studies on TaC3H gene function and also contribute to studies on the C3H gene in other species.

In Vitro Germination and Initial Seedling Development of Krantz Aloe by Smoke-saturated Water and Seed Imbibition

Krantz aloe (Aloe arborescens) is one of two aloe species currently used for the extraction of active ingredients that can be useful in the cosmetic and pharmaceutical industries. However, krantz aloe plants have been frequently collected from the wild, which is threatening wild populations. In vitro tissue culture would allow the growth of krantz aloe under controlled conditions, optimizing the production of active ingredients without risk to wild populations. The establishment of cultures from krantz aloe plant explants has proved difficult as a result of the long response times of the explants and their release of polyphenols. Krantz aloe seeds are not commonly used as a means of propagation because of their low germination percentages. The objective of this study was to evaluate the effects of seed imbibition (SI) with water and the addition of smoke-saturated water (SSW) to the culture medium on the in vitro germination and initial seedling development of krantz aloe. Seeds were germinated in vitro in axenic conditions. The treatments used were the addition of 10% SSW to the culture media, SI, and a combination of both (10% SSW + SI). Daily germination was recorded and gross morphology was measured after 1 month of culture establishment. The maximum germination percentage (GP) was achieved when 10% SSW was in the medium (97.2%), followed by the combined application of 10% SSW + SI (96.6%), both of which were almost 30% greater and significantly different from that of the control (69.4%). SI had an 83.3% GP. No significant differences were observed among treatments in any of the observed development parameters (leaf and root length and number). Taken together, these findings show that the use of SSW improves the in vitro germination of krantz aloe without affecting seedling development, indicating preliminarily that SSW represents a useful in vitro germination promoter for this species.