A triterpenoid saponin as an environmental friendly and biodegradable clay swelling inhibitor

Microscopic Characterization of Deformation Behavior during Kerogen Evolution: Effects of Maturity and Skeleton Moisture Content

The CH4 storage and seepage capacity of shale kerogen are the main controlling factors of the natural gas production rate, and the porosity and permeability of kerogen are greatly affected by kerogen deformation. Therefore, the study of the deformation rule and CH4 adsorption characteristics of kerogen at different maturities and skeleton moisture contents has an important impact on the proper understanding of the development potential of shale gas reservoirs. In this paper, kerogen maturity (II-A, II-B, II-C, and II-D) and skeleton moisture content (0.0, 0.6, 1.2, 1.8, and 2.4 wt %) were considered. The deformation of kerogen, the adsorption of CH4 after deformation, and the quadratic deformation induced by CH4 were studied by using Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD). The results show that the kerogen volume strain increases with increasing skeleton moisture content, following the order II-A < II-B < II-C < II-D for the same moisture content. The density of the kerogen matrix decreases, and porosity increases with rising moisture content. The void fraction of immature kerogen decreases with increasing water content, while the opposite is true for postmature kerogen. The presence of skeleton moisture decreases the CH4 adsorption capacity of immature kerogen and increases the CH4 adsorption capacity of postmature kerogen. The chemical structure of immature kerogen is relatively soft, making its volume more affected by CH4 adsorption compared with postmature kerogen. In the same water environment, postmature kerogen has greater CH4 storage, diffusion, and seepage capacity compared to those of immature kerogen, suggesting that reservoirs with high organic matter maturity should be prioritized for development.

Acylated Inulin as a Potential Shale Hydration Inhibitor in Water Based Drilling Fluids for Wellbore Stabilization

Shale hydration dispersion and swelling are primary causes of wellbore instability in oil and gas reservoir exploration. In this study, inulin, a fructo-oligosaccharide extracted from Jerusalem artichoke roots, was modified by acylation with three acyl chlorides, and the products (C10-, C12-, and C14-inulin) were investigated for their use as novel shale hydration inhibitors. The inhibition properties were evaluated through the shale cuttings hot-rolling dispersion test, the sodium-based bentonite hydration test, and capillary suction. The three acylated inulins exhibited superb hydration-inhibiting performance at low concentrations, compared to the commonly used inhibitors of KCl and poly (ester amine). An inhibition mechanism was proposed based on surface tension measurements, contact angle measurements, Fourier-transform infrared analysis, and scanning electron microscopy. The acylated inulin reduced the water surface tension significantly, thus, retarding the invasion of water into the shale formation. Then, the acylated inulin was adsorbed onto the shale surface by hydrogen bonding to form a compact, sealed, hydrophobic membrane. Furthermore, the acylated inulins are non-toxic and biodegradable, which meet the increasingly stringent environmental regulations in this field. This method might provide a new avenue for developing high-performance and ecofriendly shale hydration inhibitors.

New magnetic nanocomposite Fe3O4@Saponin/Cu(II) as an effective recyclable catalyst for the synthesis of aminoalkylnaphthols via Betti reaction

In this research, a new magnetic nanocomposite Fe₃O₄@Saponin/Cu(II) based on quillaja saponin was prepared and the catalyst structure was characterized thoroughly using FT-IR, EDS, TGA, XRD, VSM, HR-TEM, SEM, ICP, BET analyzes. The catalyst prepared in the three-component synthesis of several Betti bases, 1-(α-aminoalkyl)naphthols, under environmentally friendly conditions was used. The advantage of this reaction is the high efficiency of the products and the short reaction time. Furthermore, Fe₃O₄@Saponin/Cu(II) nano-catalyst is recoverable magnetically and is reusable for other processes with no reduction in its activity.

Structure-function relationship of licorice (Glycyrrhiza glabra) root extract-xanthan/guar gum mixture in a high sugar content system

BACKGROUND

Foam-gels are one of the most important multicomponent-model systems in aerated confectionery, and an investigation of their microstructure is desirable. In this research, the structure-function relationship of xanthan gum/guar gum (XG/GG) and licorice (Glycyrrhiza glabra) root extract powder (LEP) was investigated in a high-sugar medium. Foam-gel systems were prepared at 4:10% to 8:20% ratios of LEP to biopolymer.

RESULTS

The results show that increasing the LEP content reduced both the melting point and enthalpy, probably due to higher overrun and weaker junctions. Boosting the XG/GG ratio led the enhancement of mechanical properties, whereas increasing the LEP concentration weakened all textural parameters, which could be due to the poor structure of the network in the presence of the foaming agent, increased moisture content and overrun. In the whipped mixture samples containing 10 g kg^-1 XG/GG, higher foaming capacity was observed. By increasing the level of biopolymers, smaller and more uniform air cells were formed according to a scanning electron microscopical study. At higher concentration of LEP, smaller bubbles and increased porosity were seen, which could be attributed to the availability of surfactant in the interfacial layer.

CONCLUSION

Maximum structural strength was achieved at a 4:20 ratio of LEP to XG/GG. In rheological experiments, pseudoplastic behavior was seen in all samples. Generally, this model system can be simulated for other herbal extracts containing natural surfactants such as saponins. Achieving a more detailed understanding of these structures and their interactions could help in formulating novel food products. © 2021 Society of Chemical Industry.

Copolymer nanocomposites with strong adsorption of exfoliated silicate nanosheets and high-temperature stability

The designed copolymer nanocomposites with well exfoliated and dispersed silicate nanosheets, strongly adsorbed on polymer chains.

Rheological Behavior and Filtration of Water-Based Drilling Fluids Containing Graphene Oxide: Experimental Measurement, Mechanistic Understanding, and Modeling

Any improvement in drilling technology is critical for developing the oil and gas industry. The success of drilling operations largely depends on drilling fluid characteristics. Drilling fluids require enough viscosity to suspend the particles and transport them to the surface and enough capability to control the fluid loss into the formation. Rheology and filtration characteristics of drilling fluids are crucial factors to consider while ensuring the effectiveness of a drilling operation. Graphene oxide (GO), xanthan gum (XG), and low-viscosity carboxymethyl cellulose (CMC LV) are being utilized in this research to produce high-performance, low-solid water-based drilling fluids (WDFs). Rheological and filtration behaviors of GO/XG/CMC LV-WDF were investigated as a function of GO, XG, and CMC LV at low concentrations (0.0-0.3% w/w) and atmospheric conditions. According to the findings, GO improved the rheological and filtration capabilities of the WDF. By adding 0.15 wt % GO, shear stress could be doubled, especially at a high shear rate of 1022 s-1. The plastic viscosity of the fluid could be expanded from 6 to 13 centipoise, and a fluid loss of 8.7 mL over 30 min was observed during the API fluid test, which would be lower than the suggested fluid loss value (15.0 mL) for water-based mud. At the same concentration of XG and CMC LV, XG had a more significant influence on rheological characteristics in the presence of GO. Adding 0.3 wt % XG could increase fluid shear stress from 20.21 to 30.21 Pa at a high shear rate of 1022 s-1. In contrast, CMC LV had more impact on filtration properties, acting as a filtration control agent by decreasing the API fluid loss of fluid from 21.4 to 14.2 mL over 30 min. The addition of XG and CMC LV to the GO solution may influence the microstructure of the filter cake, resulting in a tree-root morphology. Indeed, in the GO/CMC LV solution, the individual platelets may bind together, form a jellyfish shape, and block the micropores. The incorporation of CMC LV helped develop compact filter cakes, resulting in excellent filtration. Five rheological models were employed to match the fluid parameters quantitatively. The Herschel-Bulkley model outperformed the other models in simulating fluid rheological behavior. The findings of this study can be utilize to provide low-cost, stable, and environmentally compatible additives for drilling low-pressure, depleted, and fractured oil and gas reservoirs.

Molecular modeling for potential cathepsin L inhibitor identification as new anti-photoaging agents from tropical medicinal plants

Ultraviolet exposure can cause photoaging toward the human skin which is begun by the inflammation on the exposure area, also resulting in activation of a degradative enzyme cathepsin L. This enzyme is one of the interesting novel therapeutic targets for antiaging agents. Three plants, named Kleinhovia hospita, Aleurites moluccana, and Centella asiatica, are well-known in the tropical region as anti-inflammatory herbs. The aims of this study were to predict the antiaging activity of the 31 compounds from these plants via inhibition of cathepsin L. All compounds were minimized their energies and then used in molecular docking. After that, molecular dynamics (MD) simulation was employed for the 5 candidate ligands and the positive control; schinol. Interaction analysis results of the pre-MD and post-MD simulation structures were obtained. Furthermore, a toxicity test was performed using ADMET Predictor 7.1. Based on the molecular docking and the MD simulation results, kleinhospitine A, β-amyrin, and castiliferol exhibited lower binding free energy than schinol (-27.0925, -28.6813, -26.0037 kcal/mol) and also had interactions with the S´ region binding site. The toxicity test indicated that β-amyrin is the most potential candidate since it exhibited the lowest binding energy and the high safety level.

Surface activity and foaming properties of saponin-rich plants extracts

Saponins are amphiphilic glycosidic secondary metabolites produced by numerous plants. So far only few of them have been thoroughly analyzed and even less have found industrial applications as biosurfactants. In this contribution we screen 45 plants from different families, reported to be rich in saponins, for their surface activity and foaming properties. For this purpose, the room-temperature aqueous extracts (macerates) from the alleged saponin-rich plant organs were prepared and spray-dried under the same conditions, in presence of sodium benzoate and potassium sorbate as preservatives and drying aids. For 15 selected plants, the extraction was also performed using hot water (decoction for 15 min) but high temperature in most cases deteriorated surface activity of the extracts. To our knowledge, for most of the extracts this is the first quantitative report on their surface activity. Among the tested plants, only 3 showed the ability to reduce surface tension of their solutions by more than 20 mN/m at 1% dry extract mass content. The adsorption layers forming spontaneously on the surface of these extracts showed a broad range of surface dilational rheology responses - from null to very high, with surface dilational elasticity modulus, E' in excess of 100 mN/m for 5 plants. In all cases the surface dilational response was dominated by the elastic contribution, typical for saponins and other biosurfactants. Almost all extracts showed the ability to froth, but only 32 could sustain the foam for more than 1 min (for 11 extracts the foams were stable during at least 10 min). In general, the ability to lower surface tension and to produce adsorbed layers with high surface elasticity did not correlate well with the ability to form and sustain the foam. Based on the overall characteristics, Saponaria officinalis L. (soapwort), Avena sativa L. (oat), Aesculus hippocastanum L. (horse chestnut), Chenopodium quinoa Willd. (quinoa), Vaccaria hispanica (Mill.) Rauschert (cowherb) and Glycine max (L.) Merr. (soybean) are proposed as the best potential sources of saponins for surfactant applications in natural cosmetic and household products.

Experimental Investigation of the Effects of Drilling Fluid Activity on the Hydration Behavior of Shale Reservoirs in Northwestern Hunan, China

The interaction between drilling fluid and shale has a significant impact on wellbore stability during shale oil and gas drilling operations. This paper investigates the effects of the drilling fluid activity on the surface and osmotic hydration characteristics of shale. Experiments were conducted to measure the influence of drilling fluid activity on surface wettability by monitoring the evolution of fluid-shale contact angles. The relationship between drilling fluid activity and shale swelling ratio was determined to investigate the osmotic hydration behavior. The results indicate that, with increasing drilling fluid activity, the fluid–shale contact angles gradually increase—the higher the activity, the faster the adsorption rate; and the stronger the inhibition ability, the weaker the surface hydration action. The surface adsorption rate of the shale with a KCl drilling fluid was found to be the highest. Regarding the osmotic hydration action on the shale, the negative extreme swelling ratio (b) of the shale was found to be: bKCl < bCTAB < bSDBS. Moreover, based on the relationship between the shale swelling ratio and drilling fluid activity, shale hydration can be divided into complete dehydration, weak dehydration, surface hydration, and osmotic hydration, which contributes to the choice of drilling fluids to improve wellbore stability.

Study on the Mechanism of Ionic Stabilizers on Shale Gas Reservoir Mechanics in Northwestern Hunan

The shale of the lower Cambrian Niutitang formation in northwestern Hunan is an ideal reservoir for shale gas. There is a close connection between borehole stability and drilling fluid in shale gas drilling. Ionic stabilizer is a new type of stratum consolidation agent that inhibits the hydration expansion of clay minerals and improves mechanical strength of the borehole. The traditional idea of pore wall protection is to use drilling fluid additives to prevent shale from interacting with water. However, ionic stabilizer can change the hydrophilic of clay minerals in shale, making the particles become hydrophobic and dense, therefore, the formation stability can be enhanced simultaneously. The material used in this paper is different from the normal ionic stabilizer, some chemical bonds that have been changed in the new material called enhanced normality ionic (ENI) stabilizer. This paper utilized the shale samples those obtained from Niutitang formation to study the connection between ENI and the mechanical properties of shale. Mechanical tests and microscopic pore tests were performed on different samples which were soaked in water and the ENI with different concentrations. It has been found through tests that ENI can inhibit the development of shale pores, and as the concentration increases, the inhibition increases. In addition, as the ENI concentration increases, the uniaxial compressive strength and Young’s modulus of the shale increase, and the ratio of stability coefficients decreases. It can be concluded that the ENI can improve the mechanical strength of carbon shale, and prevent the development of rock damage. Moreover, it can improve the ability of rock to resist damage, and enhance borehole stability initiatively.

A novel non-ionic surfactant extract derived from Chromolaena odarata as shale inhibitor in water based drilling mud

High performance clay swelling inhibitors play a vital role in improving inhibition characteristics of shales. The linkages between the inhibition's characteristics of the non-ionic surfactant extract from bio-based inhibitors are yet to be fully explored in the literature. This paper reports the use of a crude extract containing saponins from Chromolaena odorata (CO) leaf, which act as surfactants for inhibiting shale hydration. Determination of the inhibitive property of nonionic surfactant was made through measurements of surface-active properties, inhibition tests, filtration, rheological and strength test.

The experimental findings on CO showed that it was highly compatible and very stable with conventional water-based drilling fluids (WBDFs), a highly effective shale inhibitor and a works through plugging and viscosity acting effect in the shale system.