A novel resin-based nanocomposite-coated sand proppant is introduced to address the issue of proppant flowback in post-fracturing fluid flowback treatments and hydrocarbon production. Self-aggregation in the water environment is the most attractive aspect of these developed proppants. In this work, sand was sieve-coated with 0.1% multiwalled carbon nanotubes (MWCNTs) followed by optimized thin and uniform resin (polyurethane) spray coating in the concentration range of 2 to 10%. Quantitative and qualitative evaluations have been carried out to assess the self-aggregation capabilities of the proposed sand proppants where no flowback was witnessed at 4% polyurethane coating containing 0.1% MWCNTs. This applied resin incorporating MWCNT coating was characterized by field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy depicted the dispersed presence of MWCNTs into polyurethane resin corroborated by the presence of 38% elemental carbon on the sand substrate. Proppant crushing resistance tests were conducted, including proppant pack stress−strain response, compaction, and fines production. It was found that the proposed sand proppant decreased the proppant pack compaction by ∼25% compared to commonly used silica sand with the ability to withstand high closure stress as high as 55 MPa with less than 10 wt % fines production. The surface wettability was determined by the sessile drop method. The application of resin incorporating MWCNT coating layers changed the sand proppant wetting behavior to oil-wet with a contact angle of ∼124°. Thermogravimetric analyses revealed a significant increment in thermal stability, which reached up to 280 °C due to the addition of MWCNTs as reinforcing nanofillers.
The formation of mineral scale has been a major constraint in the oilfield operations as it leads to numerous flow assurance issues. Scale deposition in the formation and production tubing can restrict the flow of hydrocarbon and interferes with the running and operation of downhole equipment. Scale inhibition squeeze treatment is one of the most common form of scale prevention. Although current squeeze treatment is the optimal way to prevent scale from depositing, it is still lack in certain aspect such as adsorption ability and retention time within the rock formation. This paper presents promising advantages of engaging nanotechnology to enhance current scale inhibition treatment. Experimental studies were carried out to examine the potential benefits of using graphene oxide and carbon nanotubes to increase the adsorption of conventional scale inhibitor, ethylenediaminetetraacetic acid (EDTA) on rock formation in a process called nano-carbon enhanced squeeze treatment (NCEST). This process involves treating the rock surface in the near wellbore region with nanomaterials that allow better adsorption capacity of scale inhibitor. Analysis testing using various techniques including field-emission scanning electron microscopy, energy-dispersive X-ray and ultraviolet-visible spectrophotometer were conducted to study the adsorption, retention and bonding of the scale inhibitor with nanomaterials and rock. NCEST technique was observed to significantly increase the adsorption of EDTA on rock sample treated with nanomaterials with a maximum adsorption of 180 mg/g compared to 51 mg/g on rock sample without nanomaterials treatment. In terms of cost-benefit, it is estimated to have significant reduction in operating expenses (up to 50%) after implementing the NCEST technique compared to that of conventional squeeze treatment.
Seeds of a renowned medicinal plant, giant dodder (Cuscuta reflexa), were assessed to appraise the effect of solvent and extraction technique variation on antioxidants potential. Dodder seed, also called cuscuta seed, has been considered superb tonic in traditional herbal medication for eyes, liver, spleen and kidney. Results show that selected solvent and procedure plays a key role in the composition and activity of extractable material. Three extraction procedures Orbital shaker, Decoction and Ultrasonic assisted extraction and five different solvents n-hexane, ethyl acetate, 100% methanol, 80% methanol and 60% methanol were used to get optimized conditions. Total phenolic and flavonoids content were found maximum in the extracts of aqueous organic system containing 80% methanol in Ultrasonic assisted extraction method but in case of tannins ethyl acetate and Orbital shaker extraction was found more suitable partner. Antioxidant estimation assays showed a little bit variation as DPPH and ABTS exhibited maximum inhibition in 80% methanol and Ultrasonic assisted extraction but 100% methanol was found better for FRAP assay. Decoction results were mostly in between the both Orbital shaker and Ultrasonic assisted extraction. Overall results indicate that coexistence of polar solvents and Ultrasonic assisted extraction gives a better choice for extractability of potent antioxidants from seeds. HPLC analysis confirmed presence of valuable phenolic acids. Pearson’s correlation coefficient reveals a significant relationship between extracted components and antioxidant capacity P< 0.05 or 0.01.
Hydraulic fracturing is a widely employed well stimulation technique in which a synthesized fracking fluid is pumped into the well bore at high pressures to propagate fractures in rock formation matrix for hydrocarbon production. Proppant being one of the essential component of fracturing fluid is used to keep the hydraulically induced fractures open and conductive by acting as a mechanically strong support particle. Hydraulic fracturing operations are gradually shifting into deeper and low permeability (tight) formation at elevated temperature and pressure conditions at which conventionally used silica sand is becoming unviable as proppant due to its crushing. For resin-coated sand (RCS), temperatures greater than 60°C under high pressures, the glass transition temperature (Tg) threshold limit of polyurethane-based resin coating is reached at which this applied coating tends to soften that results reduction in the mechanical strength of the coated sand pack. Glass beads are also considered as good contestant for proppant that were selected in this study due to their high roundness and sphericity. They were drip coated with urethane resin incorporated with three different concentrations of 0.1 wt%, 0.5 wt% and 1 wt% carbon nanotubes (CNTs) and reduced graphene oxide (rGO) nanofillers, respectively. Crush test analysis by means of Universal Testing Machine (UTM) revealed significant improvement in the mechanical strength of coated glass bead proppants. 0.5 wt% loading of CNTs into urethane resin proved to be the best optimum concentration at which the mechanical strength of the coated glass bead improved by 84% along with 40% reduction in fines generation due to its containment within the applied coating. Crush test results also further revealed that nanofillers concentration loadings greater than the optimum threshold limit into urethane resin promoted their mutual agglomeration that resulted in profound reduction in mechanical strength of coated glass beads therefore resulting in more crushing and higher generation of undesired and detrimental fine particles.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.