Herschel–Bulkley rheological parameters of lightweight colloidal gas aphron (CGA) based fluids

Cellulose derivatives as environmentally-friendly additives in water-based drilling fluids: A review

The application of cellulose derivatives including carboxymethyl cellulose (CMC), polyanionic cellulose (PAC), hydroxyethyl cellulose (HEC), cellulose nanofibrils (CNFs), and cellulose nanocrystals (CNCs) has gained enormous interest, especially as environmentally friendly additives for water-based drilling fluids (WBDFs). This is due to their sustainable, biodegradable, and biocompatible nature. Furthermore, cellulose nanomaterials (CNMs), which include both CNFs and CNCs, possess unique properties such as nanoscale dimensions, a large surface area, as well as unique mechanical, thermal, and rheological performance that makes them stand out as compared to other additives used in WBDFs. The high surface hydration capacity, strong interaction with bentonite, and the presence of a complex network within the structure of CNMs enable them to act as efficient rheological modifiers in WBDFs. Moreover, the nano-size dimension and facilely tunable surface chemistry of CNMs make them suitable as effective fluid loss reducers as well as shale inhibitors as they have the ability to penetrate, absorb, and plug the nanopores within the exposed formation and prevent further penetration of water into the formation. This review provides an overview of recent progress in the application of cellulose derivatives, including CMC, PAC, HEC, CNFs, and CNCs, as additives in WBDFs. It begins with a discussion of the structure and synthesis of cellulose derivatives, followed by their specific application as rheological, fluid loss reducer, and shale inhibition additives in WBDFs. Finally, the challenges and future perspectives are outlined to guide further research and development in the effective utilization of cellulose derivatives as additives in WBDFs.

Fabrication of porous adsorbents from eco-friendly aqueous foam for high-efficient removal of cationic dyes and sustainable utilization assessment

Porous materials applied in environmental remediation have received researchers' extensive attention recently, but the related green and convenient preparation method is rarely reported. Here, we recommended a green and convenient strategy for the fabrication of porous material via aqueous foam templates, which was synergistically stabilized by Codonopsis pilosula (CP) and clay minerals of attapulgite (APT). The characterization results revealed that the APT was modified by organic molecules leached from CP and anchored at the air-water interface, which improved the foam stability significantly. The novel porous material of polyacrylamide/Codonopsis pilosula/attapulgite (PAM/CP/APT) templated from the aqueous foam via a polymerization reaction had excellent adsorption capacity for the cationic dyes methyl violet (MV) and methylene blue (MB), and the adsorption capacity can reach 755.85 mg/g and 557.64 mg/g, respectively. More importantly, the adsorption capacity of spent adsorbent material was still over 200 mg/g after being recycled five times through a simple carbonization process, and then it was added to the plant pot, the total biomass was increased by about 86.42%. This study provided a green and sustainable pathway for the preparation, application and subsequent processing of porous materials.

On the Response of a Herschel-Bulkley Fluid Due to a Moving Plate

In this paper, we study the boundary-layer flow of a Herschel-Bulkley fluid due to a moving plate; this problem has been experimentally investigated by others, where the fluid was assumed to be Carbopol, which has similar properties to cement. The computational fluid dynamics finite volume method from the open-source toolbox/library OpenFOAM is used on structured quad grids to solve the mass and the linear momentum conservation equations using the solver "overInterDyMFoam" customized with non-Newtonian viscosity libraries. The governing equations are solved numerically by using regularization methods in the context of the overset meshing technique. The results indicate that there is a good comparison between the experimental data and the simulations. The boundary layer thicknesses are predicted within the uncertainties of the measurements. The simulations indicate strong sensitivities to the rheological properties of the fluid.

Mechanistic Study of Micro-bubble Fluid Infiltration through the Fractured Medium

Drilling in depleted reservoirs has many challenges due to the overbalance pressure. Another trouble associated with overbalance drilling is differential sticking and formation damage. Low-density drilling fluid is an advanced method for drilling these depleted reservoirs and pay zones with different pressures to balance the formation pore pressure and hydrostatic drilling fluid pressure. This study investigated the infiltration of a micro-bubble fluid as an underbalanced drilling method in fractured reservoirs. A novel method has been presented for drilling permeable formations and depleted reservoirs, leading to an impressive reduction in costs, high-tech facilities, and drilling mud invasion. It also reduces mud loss, formation damages, and skin effects during the drilling operation. This paper studied micro-bubble fluid infiltration in a single fracture, and a synthetic metal plug investigated the bridging phenomenon through the fractured medium. Moreover, the effects of fracture size, bubble size, and a pressure differential of fracture ends have been thoroughly analyzed, considering the polymer and surfactant concentrations at reservoir conditions, including the temperature and overburden pressure. In this study, nine experimental tests were designed using the design of experiment, Taguchi method. The results indicated that higher micro-bubble fluid mixing speed values make smaller bubbles with lower blocking ability in fracture (decrease the chance of blocking more than two times). On the other hand, a smaller fracture width increases the probability of bubble bridges in the fracture but is not as crucial as bubble size. As a result, drilling fluid infiltration in fractures and formation damages decreases in the condition of overbalanced drilling pressure differences of about 200 psi.

Fabrication and Characterization of Whey Protein—Citrate Mung Bean Starch—Capsaicin Microcapsules by Spray Drying with Improved Stability and Solubility

Capsaicin was microencapsulated in six different wall systems by spray drying whey protein and citrate mung bean starch at various ratios (10:0, 9:1, 7:3, 5:5, 3:7, 1:9, 0:10) to improve its stability and water solubility and reduce its pungency. The morphological, rheological, storage stability, and physicochemical properties of capsaicin emulsion and capsaicin microcapsules were characterized. As a result, the yield of six capsaicin microcapsules was 19.63–74.99%, the encapsulation efficiency was 26.59–94.18%, the solubility was 65.97–96.32%, the moisture content was lower than 3.63% in all systems, and particle size was broadly distributed in the range of 1–60 μm. Furthermore, microcapsules with high whey protein content in the encapsulation system had an excellent emulsifier effect and wetness, smooth particle surface, and higher lightness (L*). Moreover, the system formed by composite wall materials at a ratio of whey protein to citrate mung bean starch of 7:3 had the highest retention rate and the best stability. The overall results demonstrate that whey protein combined with citrate mung starch through spray drying could be a promising strategy to produce microcapsules of poorly water-soluble compounds such as capsaicin.

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.

Functional nanoparticle reinforced starch-based adhesive emulsion: Toward robust stability and high bonding performance

Sustainable bio-based adhesive is a promising substitute for petroleum-based adhesives to alleviate serious environmental and health problems. In this work, a nanoengineered starch-based adhesive was fabricated by grafting vinyl acetate (VAc) onto starch molecule and subsequently incorporating the functional nanoparticle [TiO₂-coupling-poly(butyl acrylate, BA), TKB] to overcome the drawbacks present in conventional nanocomposite adhesive. Results showed that the presence of BA altered the surface property of TKB, leading to improved dispersion. In the adhesive with 4% (mass ratio to starch) TKB, TKB aggregates played the role as a sliding bridge, which significantly promoted the storage stability and shear strength in both dry and wet states. Additionally, the latex film with 4% TKB exhibited high compatibility and water resistance due to the promoted hydrophobicity. This study provides a fundamental insight into the improvement of functional nanoparticles on the performance of starch-based adhesive, suggesting a novel strategy for designing high-performance bio-adhesive.

Application of modified starch in high-temperature-resistant colloidal gas aphron (CGA) drilling fluids

Colloidal gas aphrons (CGA) are finding increasing application in depleted oil and gas reservoirs because of their distinctive characteristics. To overcome the limitations of its application in high-temperature drilling, a modified starch foams stabilizer WST with a temperature resistance of 160 °C was synthesized via radical polymerization. The chemical structure of WST was characterized by Fourier infrared spectroscopy and results showed that all three monomers acrylamide, 2-acrylamido-2-methyl-1-propane sulfonic acid, and N-vinylpyrrolidone have been grafted onto starch efficiently. Based on the microscopic observations, highly stable aphrons have been successfully generated in the WST-based CGA drilling fluids within 160 °C, and most aphrons lie in the range of 10–150 μm. WST can provide higher viscosity at high temperatures compared to xanthan gum, which helps to extend foam life and stability by enhancing the film strength and slowing down the gravity drainage. Results show that WST-CGA aged at elevated temperatures (120–160 °C) is a high-performance drilling fluid with excellent shear-thinning behavior, cutting carrying capacity, and filtration control ability. The significant improvement of filtration control and well-building capability at high temperatures is an important advantage of WST-CGA, which can be attributed to the enhancement of mud cake quality by WST.

A Novel Amphoteric Polymer as a Rheology Enhancer and Fluid-Loss Control Agent for Water-Based Drilling Muds at Elevated Temperatures

Exploring deep and ultradeep wells has rapidly become more significant to meet the global demand for oil and gas. The study of rheological and filtration-loss properties is essential to designing drilling muds and determining their performance under operational conditions. Rheological and filtration-loss properties of drilling muds were found to have a negative impact when exposed to elevated temperatures in the wells. In this study, an amphoteric polymer (abbreviated to PEX) was synthesized and characterized using a combination of analyses: FTIR, SEM, 13CNMR, and TGA. The synthesized PEX was used as an additive in water-based drilling muds to improve rheological properties and reduce fluid loss at elevated temperatures (180-220 °C). The experimental results demonstrated that inclusion of an optimal concentration of PEX (0.3 wt %) into the drilling mud formulation increased the rheological properties by 62.3% and decreased the filtration loss by 63.5% at an aging temperature of 180 °C. Moreover, PEX was found to perform superbly compared to polyanionic cellulose (PAC-LV) and polyacrylamide (PAM), the widely used drilling mud additives. PEX not only improved the rheological properties and reduced the filtration loss behavior but also bolstered the thermostability of the drilling mud formulation. It was concluded that the rigidity and amphoteric nature of PEX accounted for the exceptional performance and temperature resistance for PEX-drilling mud formulations. Succinctly, PEX exhibits admirable properties in smart drilling mud formulations for drilling operations under high-temperature geothermal conditions. Moreover, in terms of rheological models, the Herschel-Bulkley model adequately described the rheological properties of all the studied drilling mud formulations.