Viscosity Reduction Research Articles

Combining Thermal Effect and Mobility Control Mechanism to Reduce Water Cut in a Sandstone Reservoir in Kazakhstan.

The application of polymer flooding is currently under investigation to control water cut and recover residual oil from a giant sandstone reservoir in Kazakhstan, where the water cut in most producers exceeds 90%, leaving substantial untouched oil in the porous media. The primary objective of this research is to explore the feasibility of a novel approach that combines the mechanisms of mobility control by polymer injection and the thermal effects, such as oil viscosity reduction, by utilizing hot water to prepare the polymer solution. This innovative hybrid method's impact on parameters like oil recovery, resistance factor, and mobility was measured and analyzed. The research involved an oil displacement study conducted by injecting a hot polymer at a temperature of 85 °C, which is higher than the reservoir temperature. Incremental recovery achieved through hot polymer injection was then compared to the recovery by conventional polymer flooding and the conventional surfactant-polymer-enhanced oil recovery techniques. The governing mechanisms behind recovery, including reductions in oil viscosity, alterations in polymer rheology, and effective mobility control, were systematically studied to comprehend the influence of this proposed approach on sweep efficiency. Given the substantial volume of residual oil within the studied reservoir, the primary objective is to improve the sweep efficiency as much as possible. Conventional polymer flooding demonstrated a moderate incremental oil recovery rate of approximately 48%. However, with the implementation of the new hybrid method, the recovery rate increased to more than 52%, reflecting a 4% improvement. Despite the polymer's lower viscosity during hot polymer flooding, which was observed by the lower pressure drop in contrast to the conventional polymer flooding scenario, the recovery factor was higher. This discrepancy indicates that while polymer viscosity decreases, the activation of other oil displacement mechanisms contributes to higher oil production. Applying hybrid enhanced oil recovery mechanisms presents an opportunity to reduce project costs. For instance, achieving comparable results with lower chemical concentrations is of practical significance. The potential impact of this work on enhancing the profitability of chemically enhanced oil recovery within the sandstone reservoir under study is critical.

Research on the quantitative relationship of the viscosity reduction effect of large-ring cyclodextrin on potato starch during gelatinization process and mechanism analysis

Starch is extensively used across various fields due to its renewable properties and cost-effectiveness. Nonetheless, the high viscosity that arises from gelatinization poses challenges in the industrial usage of starch at high concentrations. Thus, it's crucial to explore techniques to lower the viscosity during gelatinization. In this study, large-ring cyclodextrins (LR-CDs) were synthesized from potato starch (PS) by using 4-α-glucanotransferase and then added to PS to alleviate the increased viscosity during gelatinization. The results from rapid viscosity analyzer (RVA) demonstrated that the inclusion of 5 % (w/w) LR-CDs markedly reduced the peak viscosity (PV) and final viscosity (FV) of PS by 49.85 % and 28.17 %. In addition, there was a quantitative relationship between PV and LR-CDs. The equation was fitted as y = 2530.73×e−x/2.48+1832.79, which provided a basis for the regulation of PS viscosity. The mechanism of LR-CDs reducing the viscosity of PS was also studied. The results showed that the addition of LR-CDs inhibited the gelatinization of PS by enhancing orderliness and limiting water absorption, resulting in a decrease in viscosity. This study provides a novel method for reducing the viscosity of starch, which is helpful for increasing its concentration and reducing energy consumption in industrial applications.

Preparation of EVAM-g-NSiO2 nanocomposite pour point depressant and its effect on rheological properties of model waxy oil

Modified ethylene-vinyl acetate copolymer (EVAM) and amino-functionalized nano-silica (NSiO2) particles were employed as the base materials for the synthesis of the nanocomposite pour point depressant designated as EVAM-g-NSiO2. This synthesis involved a chemical grafting process within a solution system, followed by a structural characterization. Moreover, combining macro-rheological performance with microscopic structure observation, the influence of the nanocomposite pour point depressant on the rheological properties of the model waxy oil system was investigated. The results indicate that when the mass ratio of NSiO2 to EVAM is 1:100, the prepared EVAM-g-NSiO2 nanocomposite pour point depressant exhibits excellent pour point reduction and viscosity reduction properties. Moreover, the nanocomposite pour point depressant obtained through a chemical grafting reaction demonstrates structural stability (the bonding between the polymer and nanoparticles is stable). The pour points of model waxy oils doped with 500 mg/kg ethylene-vinyl acetate copolymer (EVA), EVAM, and EVAM/SiO2 were reduced from 34 °C to 23, 20, and 21 °C, respectively. After adding the same dosage of EVAM-g-NSiO2 nanocomposite pour point depressant, the pour point of the model wax oil decreased to 12 °C and the viscosity at 32 °C decreased from 2399 to 2396.9 mPa ·s, achieving an impressive viscosity reduction rate of 99.9%. Its performance surpassed that of EVA, EVAM, and EVAM/SiO2. The EVAM-g-NSiO2 dispersed in the oil phase acts as the crystallization nucleus for wax crystals, resulting in a dense structure of wax crystals. The compact wax crystal blocks are difficult to overlap with each other, preventing the formation of a three-dimensional network structure, thereby improving the low-temperature flowability of the model waxy oil.

Ascorbic acid-mediated reduction of arabinoxylan viscosity through free radical reactions

Arabinoxylan (AX) is a potential natural food additive that can enhance the textural properties of food. However, the addition of ascorbic acid (AA) can easily lead to a decrease in the viscosity of AX, which poses a challenge in the development of AX-rich foods. Therefore, the purpose of this study is to elucidate the mechanisms behind the reduction in AX viscosity in the presence of AA. The results indicated that AA could reduce the apparent viscosity and molecular weight of AX without significantly affecting the monosaccharide composition, suggesting a potential mechanism related to the cleavage of AX glycosidic bonds. Interestingly, free radicals were present in the reaction system, and the generation of free radicals under different conditions was consistent with the reduction in apparent viscosity of AX. Furthermore, the reduction in AX apparent viscosity by AA was influenced by various factors including AA concentration, reaction time, temperature, pH, and metal ions. These findings suggested that the mechanism of AX degradation may be due to AA-induced free radical generation, leading to non-selective attacks on glycosidic bonds. Therefore, this study revealed that the potential mechanism behind the reduction in AX viscosity induced by AA involved the generation of ascorbic acid radicals.

Water-Soluble Fe(III) Complex Catalyzed Coupling Aquathermolysis of Water-Heavy Oil-Methanol

In this experimental study, diverse water-soluble Fe(III) complexes were synthesized and employed to catalyze the aquathermolysis of heavy oil. A ternary reaction system comprising heavy oil, water, and methanol was established to facilitate the process. Viscometry, thermogravimetric analysis, DSC, and elemental analysis were utilized to thoroughly investigate the treated heavy oil. The findings reveal that, under optimal conditions of water, catalyst, and methanol dosage, the viscosity of heavy oil can be significantly reduced by up to 88.22% after reacting at 250 °C for 12 h. Notably, apart from viscosity reduction, the catalytic aquathermolysis also effectively removes heteroatoms such as sulfur, nitrogen, and oxygen, enabling in situ modification and viscosity reduction of heavy oil. This study demonstrates the potential of water-soluble Fe(III) complexes in enhancing the efficiency of heavy oil extraction and processing.

O-glycans Expand Lubricin and Attenuate Its Viscosity and Shear Thinning.

Lubricin, an intrinsically disordered glycoprotein, plays a pivotal role in facilitating smooth movement and ensuring the enduring functionality of synovial joints. The central domain of this protein serves as a source of this excellent lubrication and is characterized by its highly glycosylated, negatively charged, and disordered structure. However, the influence of O-glycans on the viscosity of lubricin remains unclear. In this study, we employ molecular dynamics simulations in the absence and presence of shear, along with continuum simulations, to elucidate the intricate interplay between O-glycans and lubricin and the impact of O-glycans on lubricin's conformational properties and viscosity. We found the presence of O-glycans to induce a more extended conformation in fragments of the disordered region of lubricin. These O-glycans contribute to a reduction in solution viscosity but at the same time weaken shear thinning at high shear rates, compared to nonglycosylated systems with the same density. This effect is attributed to the steric and electrostatic repulsion between the fragments, which prevents their conglomeration and structuring. Our computational study yields a mechanistic mechanism underlying previous experimental observations of lubricin and paves the way to a more rational understanding of its function in the synovial fluid.

Research and Application of Non-Steady-State CO2 Huff-n-Puff Oil Recovery Technology in High-Water-Cut and Low-Permeability Reservoirs

In response to the issues of poor water flooding efficiency, low oil production rates, and low recovery rates during the high-water-cut period in the low-permeability reservoirs of the Mutou Oilfield, the non-steady-state (NSS) CO2 huff-n-puff oil recovery technology was explored. The NSS CO2 huff-n-puff can improve the development effect of low-permeability reservoirs by replenishing the reservoir energy and significantly increasing the crude oil mobility. Experimental investigations were carried out, including a crude oil and CO2–crude oil swelling experiment, minimum miscibility pressure testing experiment, high-temperature and high-pressure microfluidic experiment, and NSS CO2 huff-n-puff oil recovery on-site pilot test. The experimental results showed that the main mechanisms of NSS CO2 huff-n-puff include dissolution, expansion, viscosity reduction, and swept volume enlargement, which can effectively mobilize the remaining oil from the various pore throats within the reservoir. The high-temperature and high-pressure microfluidic experiment achieved an ultimate recovery rate of 83.1% for NSS CO2 huff-n-puff, which was 7.9% higher than the rate of 75.2% obtained for steady injection. This method can effectively utilize the remaining oil in the corners and edges, enlarge the swept volume, and increase the recovery rate. Field trials of NSS CO2 huff-n-puff in a low-permeability reservoir in the Mutou Oilfield indicated that it cumulatively increased the oil production by 1134.5 tons. The achieved results and insights were systematically analyzed and could provide key technical support for the application of NSS CO2 huff-n-puff technology in low-permeability reservoirs, promoting the innovative development of this technology.

Microwave treatment enhances the physical and sensory quality of quinoa-enriched gluten-free bread

The suitability of microwave-assisted hydrothermally treated (MWT) quinoa flour was investigated as an ingredient for enhancing the quality of gluten-free (GF) bread fortified with quinoa. Different levels (0%, 25%, 37.5%, 50%, and 75%) of native/untreated (N) or MWT quinoa flour (30% moisture content, 9 W/g, total 8 min of microwave exposure) were evaluated to replace maize starch in a starch-based GF recipe. The hydration of the dough was adjusted to obtain similar consistency in terms of complex modulus, G1*, to compensate its increase due to quinoa addition and treatment (up to +737%). The incorporation of increasing amounts of native quinoa flour reduced dough viscosimetric profiles, delayed its gelatinization peak in DSC scans (up to +3.4 °C), and decreased the dough's development and stability during the fermentation test (the final height decreased from 88 mm for 0% quinoa to 4 mm for 75%). When substituting native by MWT quinoa flour at a certain substitution level, a reduction in the breakdown viscosity, an increase in pasting temperature, and an increase in dough development and stability during the fermentation test were noted. As a result, the MWT quinoa flour-fortified breads exhibited a higher specific volume, lower hardness, and retarded staling. In addition, sensory evaluation of the breads showed a reduction in the herbaceous off-flavour associated with the quinoa (untreated) flour, and no effect on bitterness. The experimental findings indicate the feasibility of using microwave hydrothermal treatment to improve the physical properties and sensory quality of quinoa-enriched GF bread.

The Role of Amphiphilic Nanosilica Fluid in Reducing Viscosity in Heavy Oil

Heavy oil accounts for a considerable proportion of the world’s petroleum resources, and its exploitation helps to mitigate reliance on conventional oil resources and diversify energy supply. However, due to the high viscosity and high adhesion characteristics of heavy oil, conventional methods such as thermal recovery, emulsification, and dilution have significant limitations and cannot meet the growing demands for heavy oil production. In this study, 3-propyltrimethoxysilane (MPS) was used to modify and graft amphiphilic surfactants (AS) onto nanosilica to prepare a salt-resistant (total mineralization > 8000 mg/L, Ca2+ + Mg2+ > 1000 mg/L) and temperature-resistant (250 °C) nanosilicon viscosity reducer (NSD). This article compares amphiphilic surfactants (AS) as conventional viscosity-reducing agents with NSD. FTIR and TEM measurements indicated successful bonding of 3-propyltrimethoxysilane to the surface of silica. Experimental results show that at a concentration of 0.2 wt% and a mineralization of 8829 mg/L, the viscosity reduction rates of thick oil (LD-1) before and after aging were 85.29% and 81.36%, respectively, from an initial viscosity of 38,700 mPa·s. Contact angle experiments demonstrated that 0.2 wt% concentration of NSD could change the surface of reservoir rock from oil-wet to water-wet. Interfacial tension experiments showed that the interfacial tension between 0.2 wt% NSD and heavy oil was 0.076 mN/m. Additionally, when the liquid-to-solid ratio was 10:1, the dynamic and static adsorption amounts of 0.2 wt% NSD were 1.328 mg/g-sand and 0.745 mg/g-sand, respectively. Furthermore, one-dimensional displacement experiments verified the oil recovery performance of NSD at different concentrations (0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%) at 250 °C and compared the oil recovery efficiency of 0.2 wt% NSD with different types of demulsifiers. Experimental results indicate that the recovery rate increased with the increase in NSD concentration, and 0.2 wt% NSD could improve the recovery rate of heavy oil by 22.8% at 250 °C. The study of nano-demulsification oil recovery systems can effectively improve the development efficiency of heavy oil.

Sustainable multi-functional additives: Zinc soaps from vegetable oil and fatty acids in natural rubber compounds

Zinc soaps derived from various vegetable oils and fatty acids were synthesized, and the product with the highest yield was chosen for compounding with silica-filled natural rubber (NR). Specifically, zinc soaps of coconut oil and palm oil, with yields of 72% and 73%, respectively, were prepared through precipitation and metathesis methods. Additionally, zinc soaps from palm fatty acid distillate (PFAD) and stearic acid, both with a yield of 70%, were synthesized using modified fusion and precipitation methods, respectively. Subsequently, these zinc soaps were incorporated into silica-filled NR compounds and compared with the commercial dispersing aid, Ultra flow 700 s. The results indicated that the zinc soaps played a significant role in plasticizing and lubricating the rubber compounds, as evidenced by reductions in Mooney viscosity, Mooney relaxation rate, and minimum torque (ML). Furthermore, the zinc soaps influenced curing properties by accelerating the cure process, as reflected in decreased cure time (tc90) and increased cure rate and torque difference compared to compounds without processing aid. Moreover, NR compounded with zinc soap exhibited superior mechanical properties, including higher tensile strength, elongation at break, tear strength, and hardness.

Effects of Aspergillus flavus infection on multi-scale structures and physicochemical properties of maize starch during storage

This study systematically analyzed the effect of Aspergillus flavus infection on the maize starch multi-scale structure, physicochemical properties, processing characteristics, and synthesis regulation. A. flavus infection led to a decrease in the content of starch, an increase in the content of reactive oxygen species (ROS) and malondialdehyde (MDA), a significant decrease in the activities of peroxidase (POD) and superoxide dismutase (SOD). In addition, A. flavus infection had a significant destructive effect on the double helix structure, relative crystallinity and lamellar structure of starch, resulting in the reduction of starch viscosity, affecting the viscoelastic properties of starch, and complicating the gel formation process. However, the eugenol treatment group significantly inhibited the growth of A. flavus during maize storage, protecting the multi-scale structure and processing characteristics of maize starch from being damaged. Transcriptome analysis showed that genes involved in carbohydrate synthesis in maize were significantly downregulated and genes involved in energy synthesis were significantly upregulated, indicating that maize converted its energy storage into energy synthesis to fight the invasion of A. flavus. These results of this study enriched the mechanism of quality deterioration during maize storage, and provide theoretical and technical support for the prevention of A. flavus infection during maize storage.

Investigating the mechanism of Au(III) transport using a polymer inclusion membrane with dibutyl carbitol as a carrier

In this article, firstly, the separation and transfer of Au(III) from gold chloride solution was investigated using a polymer inclusion membrane (PIM) system containing dibutyl carbitol (DBC) as carrier molecules, dioctyl phthalate (DOP), bis(2-ethyl hexyl) adipate (dioctyl adipate) (DOA) and tris (2-ethyl hexyl) phosphate (T2EHP) as plasticizers and high molecular weight polyvinyl chloride (PVC) as the base polymer. Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscope (SEM) were used to identify PIMs. Kinetic studies featuring a two-step reaction, with the first step being reversible, were conducted across various sections to investigate the processes of extraction, stripping, and transport. The effects of different stripping agents such as water, HCl, thiourea, sodium thiosulfate, and oxalic acid was investigated, and the best results were obtained with thiourea. Also, the mechanisms of Au(III) extraction and transport were studied. Under the conditions of source solution, tetrachloroaurate anionic complex AuCl4− with protonated DBC (ROR2OHM+) was extracted by ion solvation mechanism. The validity of the proposed extraction mechanism was confirmed through the use of nuclear magnetic resonance (1H NMR) spectroscopy. In order to make the membrane with the best composition and the highest efficiency, the effect of weight percentage of the carrier and plasticizer was investigated. There was an optimal value for the weight percentage of plasticizer (10–20% by weight) and carrier (40%), in which the highest flux and permeability in the membrane occurred. The effect of the viscosity of different plasticizers (DOP, DOA, and T2EHP) on the Au(III) flux was also investigated. It was found that the flux increases linearly with the reduction of plasticizer viscosity. Effect of membrane thickness on the permeability, initial flux, and efficiency of Au(III) transfer, were conducted with thickness of 120, 80, 45, and 30 μm. By reducing the thickness of the membrane, the transfer flux, permeability and percent of Au(III) transport, were improved from 12.9 × 10−3mh−1, 45.3 × 10−7molm−2s−1 and 18.2% to 26.4 × 10−3mh−1, 83.5 × 10−7molm−2s−1 and 37.3%, respectively. According to the results, a membrane with a combination of PVC:DBC:D2EHP with a weight percentage ratio of 50:40:10 with a thickness of 30 μm was suggested. Optimized results with the proposed membrane were obtained to be: extraction rate constant of 1.43 h−1, extraction percent of 99.1%, stripping rate constant of 37.5 × 10−4h−1, stripping percent of 40.9%, and permeability of 27.0 × 10−3mh−1, initial flux of 82.1 × 10−7molm−2s−1.

Synergistic collaborations between surfactant and polymer for in-situ emulsification and mobility control to enhance heavy oil recovery

Surfactant-polymer (SP) combined systems is an effective nonthermal method to enhance the heavy oil recovery, through in-situ emulsification and mobility control mechanisms. In this study, a novel SP system was developed using 0.2 wt% anionic surfactant (alkyl naphthol polyoxyethylene ether sulfonate, ANES) and 0.1 wt% polymer (partially hydrolyzed polyacrylamide, HPAM). The SP system had viscosity reduction rate of ∼ 98 %, viscosity ratio of oil to displaced water (μo/μd) of ∼ 3.95 and IFT of ∼ 0.29 mN/m, beneficial for decreasing the mobility ratio of water to heavy oil. Then, the applied performances including emulsion morphologies and stability, wettability alteration ability were systematically characterized. The results showed that the freshly O/W emulsions formed by SP system displayed uniform droplet size distribution, as well as high stability with tight interfacial film. In addition, the SP system exhibited excellent wettability alteration property with low contact angle of 18.3°. The synergistic collaboration mechanisms of surfactant and polymer include heavy oil–water interfacial tension reduction, in-situ emulsification, oil-viscosity reduction and water-viscosity increase. Finally, the static oil washing and dynamic sand-pack flooding experiments showed that the SP system exhibited high oil washing efficiency (62.89 %) and enhanced oil recovery efficiency (56.9 %) with improving the mobility controllability after the primary water-flooding process. This study indicated that the synergistic collaborations between surfactant and polymer had great potential to enhance the heavy oil recovery.

Viscosity Reduction Behavior of Carbon Nanotube Viscosity Reducers with Different Molecular Structures at the Oil–Water Interface: Experimental Study and Molecular Dynamics Simulation

Effectively enhancing oil recovery can be achieved by reducing the viscosity of crude oil. Therefore, this paper investigated the viscosity reduction behavior of carbon nanotube viscosity reducers with different molecular structures at the oil–water interface, aiming to guide the synthesis of efficient viscosity reducers based on molecular structure. This study selected carbon nanotubes with different functional groups (NH2-CNT, OH-CNT, and COOH-CNT) for research, and carbon nanotubes with varying carbon chain lengths were synthesized. These were then combined with Tween 80 to form a nanofluid. Scanning electron microscopy analysis revealed an increased dispersibility of carbon nanotubes after introducing carbon chains. Contact angle experiments demonstrated that -COOH exhibited the best hydrophilic effect. The experiments of zeta potential, conductivity, viscosity reduction, and interfacial tension showed that, under the same carbon chain length, the conductivity and viscosity reduction rate sequence for different functional groups was -NH2 < -OH < -COOH. The dispersing and stabilizing ability and interfacial tension reduction sequence for different functional groups was -COOH < -OH < -NH2. With increasing carbon chain length, conductivity and interfacial tension decreased, and the viscosity reduction rate and the dispersing and stabilizing ability increased. Molecular dynamics simulations revealed that, under the same carbon chain length, the diffusion coefficient sequence for different functional groups was -NH2 < -OH < -COOH. The diffusion coefficient gradually decreased as the carbon chain length increased, resulting in better adsorption at the oil–water interface. This study holds significant importance in guiding viscosity reduction in heavy oil to enhance oil recovery.

Filtered Saliva for Rapid and Accurate Analyte Detection for POC Diagnostics.

Saliva has shown considerable promise as a diagnostic medium for point-of-care (POC) and over-the-counter (OTC) diagnostic devices due to the non-invasive nature of its collection. However, a significant limitation of saliva-based detection is undesirable interference in a sensor's readout caused by interfering components in saliva. In this study, we develop standardized sample treatment procedures to eliminate bubbles and interfering molecules while preserving the sample's target molecules such as spike (S) protein and glucose. We then test the compatibility of the pretreatment system with our previously designed SARS-CoV-2 and glucose diagnostic biosensing systems for detecting S protein and glucose in subject saliva. Ultimately, the effectiveness of each filter in enhancing biomarker sensitivity is assessed. The results show that a 20 mg nylon wool (NW) filter shows an 80% change in viscosity reduction with only a 6% reduction in protein content, making it an appropriate filter for the salivary S protein diagnostic system. Meanwhile, a 30 mg cotton wool (CW) filter is identified as the optimal choice for salivary glucose detection, achieving a 90% change in viscosity reduction and a 60.7% reduction in protein content with a minimal 4.3% reduction in glucose content. The NW pretreatment filtration significantly improves the limit of detection (LOD) for salivary S protein detection by five times (from 0.5 nM to 0.1 nM) and it reduces the relative standard deviation (RSD) two times compared to unfiltered saliva. Conversely, the CW filter used for salivary glucose detection demonstrated improved linearity with an R2 of 0.99 and a sensitivity of 36.6 μA/mM·cm2, over twice as high as unfiltered saliva. This unique filtration process can be extended to any POC diagnostic system and optimized for any biomarker detection, making electrochemical POC diagnostics more viable in the current market.

A framework for the biophysical screening of antibody mutations targeting solvent-accessible hydrophobic and electrostatic patches for enhanced viscosity profiles

The formulation of high-concentration monoclonal antibody (mAb) solutions in low dose volumes for autoinjector devices poses challenges in manufacturability and patient administration due to elevated solution viscosity. Often many therapeutically potent mAbs are discovered, but their commercial development is stalled by unfavourable developability challenges. In this work, we present a systematic experimental framework for the computational screening of molecular descriptors to guide the design of 24 mutants with modified viscosity profiles accompanied by experimental evaluation. Our experimental observations using a model anti-IL8 mAb and eight engineered mutant variants reveal that viscosity reduction is influenced by the location of hydrophobic interactions, while targeting positively charged patches significantly increases viscosity in comparison to wild-type anti-IL-8 mAb. We conclude that most predicted in silico physicochemical properties exhibit poor correlation with measured experimental parameters for antibodies with suboptimal developability characteristics, emphasizing the need for comprehensive case-by-case evaluation of mAbs. This framework combining molecular design and triage via computational predictions with experimental evaluation aids the agile and rational design of mAbs with tailored solution viscosities, ensuring improved manufacturability and patient convenience in self-administration scenarios.

Oxidative Hydraulic Fracturing Fluid to Enhance Production from Source Rock Reservoirs

Summary The steep production declines generally observed after hydraulic fracturing in unconventional source rock reservoirs has been attributed to several potential causes. Recently, a new additive to the stimulation fluid system was proposed to extend economical longer-term production from these formations. Oxidizer-laden fracturing fluid systems are shown to create cracks and deep channels within the organic matter present in the source rock, such as kerogen, thereby increasing the source rock permeability and enhancing the hydraulic conductivity of the exposed fracture faces. To this end, the fluid design and recommendations for its application are illustrated herein. Oxidants composed of oxychlorine (ClOn−) and oxybromine (BrOn–) (where n = 0 to 4) are effective for kerogen depolymerization or degradation at depth. This study illustrates the beneficial effects of two specific oxidizers—sodium chlorite (NaClO2) and sodium bromate (NaBrO3)—on kerogen-rich source rock subjected to in-situ reservoir conditions. Source rock samples were cut and polished to test the oxidizer’s impact on the organic and inorganic regions. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were performed on the rock surface to identify specific organic matter features. The samples were then chemically treated with varying conditions of NaClO2 or NaBrO3 (concentration range: 0.013–0.054 M; temperature: 150°C; and time: 3–24 hours). Samples were returned to the scanning electron microscope for post-treatment analysis. Furthermore, the oxidants were packaged within a slickwater hydraulic fracturing fluid system for field application, and their effects on viscosity and friction reduction were also studied. SEM images and EDS maps of kerogen-rich rock samples observed before and after treatment with oxidizing fluid showed a series of cracks formed throughout the organic matter domains, where increasing the concentration of oxidizer in the treatment fluid showed a clear increase in the prevalence of cracks throughout the surface. The effect of time was also observed, as short treatment times resulted in porosity/permeability creation in the kerogen, though longer treatment times were associated with more severe degradation. Optimal conditions for NaClO2 and NaBrO3 concentrations in the additive fluid systems were different and will be herein highlighted. Each oxidizer (10–20 pptg concentration) was added to slickwater with variable friction reducer concentration (1 gpt, 2 gpt, and 4 gpt), and shear sweeps performed at both 70°F and 180°F. A negligible difference is observed between the viscosities of the base fluid and the fluid with either oxidant at low friction reducer concentration. Meanwhile, flow loop tests demonstrated that the oxidizer did not affect the friction reducer except to slightly boost the performance due to the salt effect on the polymer. Two strong oxidants, available as commodity chemicals, are shown to be effective in cracking kerogen and any present organic matter, thus creating permeable channels and enhancing the overall permeability of the exposed source rock fracture faces. Meanwhile, the proposed fracturing fluid additives display good compatibility with other slickwater fluid components, demonstrating the potential for universal usage in unconventional stimulations. The recommendations for its application as a fluid additive in slickwater are herein illustrated.

The study of galactomannans with different molecular weights and their ability to form microparticles suitable for pulmonary delivery

The influence of locust bean gum (LBG) galactomannans (GMs) molecular weight (Mw) to assemble microparticulate systems was evaluated, and carriers for deep lung delivery were developed. A commercial batch of LBG with a mannose/galactose (M/G) ratio of 2.4 (batch 1) was used to study the influence of different microwave partial acid hydrolysis conditions on carbohydrate composition, glycosidic linkages, and aqueous solutions viscosity. The microwave treatment did not affect the composition, presenting 4-Man (36–42 %), 4,6-Man (27–35 %), and T-Gal (24–25 %) as the main glycosidic linkages. Depolymerization led to a viscosity reduction (≤0.005 Pa·s) with no major impact on polysaccharide debranching. The structural composition of the LBG galactomannans were further elucidated with sequence-specific proteins using carbohydrate microarray technologies. A second batch of LBG (M/G 3.3) was used to study the impact of GMs with different Mw on microparticle assembling, characteristics, and insulin release kinetics. The low-Mw GMs microparticles led to a faster release (20 min) than the higher-Mw (40 min) ones, impacting the release kinetics. All microparticles exhibited a safety profile to cells of the respiratory tract. However, only the higher-Mw GMs allowed the assembly of microparticles with sizes suitable for this type of administration.

Synthesis and characterization of Ionic liquid supported on Zeolitic Imidazolate Framework-8 (ZIF-8) as a highly effective additive for visbreaking of petroleum vacuum bottom

In this present work, a zeolitic imidazolate framework, ZIF-8, an oil-soluble long chain Ionic Liquids, [OMIM][NTf2], was separately synthesized and characterized. Ex-situ preparation of [OMIM][NTf2]-ZIF8 (IL@ZIF8) nanostructures were performed solvothermal, and the products were specified by the several techniques including XRD, FESEM, H-NMR, FTIR, TGA and N2 adsorption-desorption. The products were evaluated as a highly effective material in visbreaking process of petroleum vacuum bottoms (PVBs). To best our knowledge, no was reported in survey on the literature for MOFs as conversion enhancer and viscosity modifier in a visbreaking process especially for atmospheric pressure and elevated temperatures of 375 -400 °C during maximum 120 min. Injection of a little amount of the synthesized products to PVBs caused to produce gaseous compounds, naphtha, middle distillates, lubricating oil and tar. However, viscosity measurement results revealed that IL@ZIF8 was ideally suited for viscosity reduction of PVBs up to 321% after cracking and conversion of PVBs to its distillates up to 1400%. Catalytic upgrading with IL@ZIF-8 also yielded a liquid with 50% light hydrocarbon without any further coke formation.

Study on the Mechanism of Carbon Dioxide Miscible Fracturing Fluid Huff and Puff in Enhanced Oil Recovery

Carbon dioxide (CO2) miscible fracturing huff-and-puff technology now plays a pivotal role in enhancing crude oil recovery rates, particularly in reservoirs with challenging physical properties, strong water sensitivity, high injection pressure, and complex water-injection dynamics. In this study, the oil-increasing mechanism and huff-and-puff effect of CO2 miscible fracturing fluid are investigated through a comprehensive experimental approach. Specifically, experiments on PVT gas injection expansion, minimum miscible pressure, and CO2 miscible fracturing fluid huff and puff are conducted on the G fault block reservoir of the J Oilfield. The experimental findings demonstrate that injecting CO2 into reservoirs leads to an expansion in oil volume, a reduction in viscosity, and an increase in saturation pressure. Crude oil extraction is further enhanced by the addition of solubilizers and viscosity reducers. The use of solubilizers not only increases oil recovery rates but also reduces the minimum miscible pressure required for effective CO2 dispersion. We also found that shut-in times, permeability, and the huff-and-puff method used all have considerable impacts on huff-and-puff recovery rates. This study offers valuable technical insights, supporting the application of CO2 miscible fracturing huff-and-puff technology to enhance oil recovery rates in low-permeability reservoirs.