Cellulose Nanocrystals: From Classical Hydrolysis to the Use of Deep Eutectic Solvents

During the last two decades, interest in cellulosic nanomaterials has greatly increased. Among these nanocelluloses, cellulose nanocrystals (CNC) exhibit outstanding properties. Indeed, besides their high crystallinity, cellulose nanocrystals are interesting in terms of morphology with high aspect ratio (length 100–1000 nm, width 2–15 nm), high specific area, and high mechanical properties. Moreover, they can be used as rheological modifier, emulsifier, or for barrier properties, and their surface chemistry opens the door to numerous feasible chemical modifications, leading to a large panel of applications in medical, electronic, composites, or packaging, for example. Traditionally, their extraction is performed via monitored sulfuric acid hydrolysis, leading to well-dispersed aqueous CNC suspensions; these last bearing negative charges (half-sulfate ester groups) at their surface. More recently, natural chemicals called deep eutectic solvents (DESs) have been used for the production of CNC in a way of green chemistry, and characterization of recovered CNC is encouraging.

Formulation of cellulose using groundnut husk as an environment-friendly fluid loss retarder additive and rheological modifier comparable to PAC for WBM

The hydrocarbon extraction and exploitation using state-of-the-art modern drilling technologies urge the use of biodegradable, environment-friendly drilling fluid and drilling fluid additives to protect the environment and humanity. As more environmental laws are enacted and new safety rules implemented to oust the usage of toxic chemicals as fluid additives, it becomes inevitable that we re-evaluate our choice of drilling fluid additives. Drilling fluids and its additives play a crucial role in drilling operations as well as project costing; hence, it is needed that we develop cost-effective environment-friendly drilling fluid additives that meet the requirements for smooth functioning in geologically complex scenarios as well as have a minimal ecological impact. The current research work demonstrates key outcomes of investigations carried out on the formulation of a sustainable drilling fluid system, where groundnut husk is used as a fluid loss additive and a rheological modifier having no toxicity and high biodegradability. Cellulose was generated from groundnut husk at two varying particle sizes using mesh analysis, which was then compared with the commercially available PAC at different concentrations to validate its properties as a comparable fluid loss retarder additive as well as a rheological modifier. In the present work, various controlling characteristics of proposed groundnut husk additive are discussed, where comparison at different concentrations with a commercially available additive, PAC, is also validated. The API filtration losses demonstrated by the (63–74) µm and the (250–297) µm proposed additive showed a decrease of 91.88% and 82.31%, respectively, from the base mud at 4% concentration. The proposed husk additives acted as a filtrate retarder additive without much deviation from base rheology and with considerably higher pH than the base mud. This investigation indicates that the proposed fluid loss additive and rheological modifier can minimize the environmental hazards and have proved to be a cost-effective eco-friendly alternative in this challenging phase of the hydrocarbon exploration industry.

A Study of the Effect of Medium Viscosity on Breakage Parameters for Wet Grinding

The rheological behavior of mineral slurries shows the level of interaction or aggregation among particles, being a process control variable in processes such as slurry transportation, dehydration, and wet grinding systems. With the aim to analyze the effect of medium viscosity in wet grinding, a series of monosize grinding ball mill tests were performed to determine breakage parameters, according to the generally accepted kinetic approach of grinding processes. A rheological modifier (polyacrylamide, PAM) was used to modify solutions viscosity. A model was proposed by means of dimensional analysis (Buckingham’s Pi theorem) in order to determine the behavior of the specific breakage rate (Sj) for a ball grinding process in terms of the rheology of the system. In addition to this, a linear adjustment was established for the relationship between specific breakage rates with and without PAM addition, based on the reduced viscosity, μr. Furthermore, within a certain interval of viscosity, it was proved that an increment of viscosity can increase the specific breakage rate, and consequently the grinding degree.

Synthesis of a Dendrimer as Rheological Modifier for Deep-Water Drilling Fluids and Study of its Interaction with Organo-Clay at Different Temperatures

As the influence of large temperature range during deep-water drilling on rheological properties of water-in-oil emulsified drilling fluids, a dendrimer synthesized from a dodecyl dibasic acid and triethylenetetramine was introduced as a rheological modifier to get a flat-rheology. The product was characterized by infrared spectroscopy and its interaction with organo-clay was studied with sedimentation experiment, optical microscope, X-ray diffraction (XRD), Transmission electron microscopy (TEM), and rheological test. The results showed that the dendrimer can improve the dispersion of organo-clay in oil and increase the distance between layers. What’s more, the addition of dendrimer can balance the yield point of base slurry (consisted of mineral oil, aqueous solution of 30wt% CaCl2, mixed emulsifier, and organo-clay) at 4 ° C and 65 ° C.

Magnesium Aluminum Silicate Nanoparticles and Polyanionic Cellulose as Additives in Low-Solid Water-Based Drilling Fluids

This work demonstrated a nanosized material, magnesium aluminum silicate (MAS), as a rheological modifier for low-solid water-based drilling fluids (WBDs) to prompt the development of the safe and high-performance low-solid WBDs. To maintain good filtration property, the polyanionic cellulose (PAC) was introduced into the MAS suspension. Meanwhile, a comprehensive comparison between MAS cooperating with PAC and BT mixing with PAC was conducted. The addition of 0.5 wt% PAC increased the yield stress and generated better shear-thinning performance for 1 wt% MAS and 4 wt% bentonite (BT). The 1 wt% MAS/0.5 wt% PAC exhibited higher yield stress and shear-thinning performance than 4 wt% BT/0.5 wt% PAC. In addition, low-concentration MAS and MAS/PAC suspensions showed higher gel strength and rapider recovery performance compared with high-concentration BT and BT/PAC suspensions. MAS and MAS/PAC maintained excellent thermal stability, compared with other common rheological modifiers, such as xanthan gum (XG), hydroxyethyl cellulose (HEC). After hot rolling at 120 °C for 16 h, WBDs prepared by MAS/PAC exhibited a slight decrease of rheological parameters, which indicated high ability to resist high temperature. The XRF, particle size distribution, and TEM analysis revealed the mechanism of low-concentration MAS and MAS/PAC maintaining better shear-thinning performance, higher gel strength and yield stress. As the excellent rheological properties and thermal stability, MAS has the great potential to be a rheological modifier for low-solid WBDs.