Herschel-Bulkley Rheological Model Research Articles

Modelling of fluid mud flow based on a three-dimensional hydrodynamic model : incorporating a 3D rheological model

Modeling fluid mud in estuaries and coastal areas is a complicated task due to its non-Newtonian characteristics. A continuous modeling approach was adopted to investigate the laminar flow of fluid mud, with a three-dimensional (3D) form of the Herschel–Bulkley rheological model introduced into the finite volume coastal ocean model (FVCOM) to calculate the apparent viscosity of fluid mud. The model was validated against two flume experiments for the laminar flow of fluid mud. The results showed that the developed model was capable of accurately reflecting the continuous distribution of velocity and density from the near-bottom to the upper water column. Based on the validated model, the difference between the 3D rheological model and a 1DV rheological model on the simulation results was assessed. The study found the results of the 1DV model and the 3D model show obvious differences. This illustrates the significant effect of apparent viscosity in horizontal direction taken into account by the 3D rheological model.

Simulation of Filter-Cake Formations on Vertical and Inclined Wells Under Elevated Temperature and Pressure

Summary Drilling fluids consist of colloidal suspensions that are made up of solid particles suspended in liquid. The aqueous component of the drilling mud invades a permeable formation due to differential pressure, leaving solid deposits on the drilled formation walls, forming a filter cake. Typical drilling fluids should create a thin, slick filter cake and fluid loss control to seal permeable zones as swiftly as possible. Tight holes, elevated levels of rotational resistance and friction, wellbore obstruction, fluid loss into formations, suboptimal well-log data, and reservoir formation impairment result from thick filter cakes and excessive filtration. Controlling infiltration of fluids to establish a minimal, low-porosity filter cake is frequently required to avoid drilling and production issues. In this study, we used computational fluid dynamics (CFD) to model the development of filter cakes induced by pipe rotation in vertical and inclined wellbore walls under elevated temperature and pressure during deep drilling. Multiple tests validate the basic model for application in both shallow and deep drilling operations. By use of an Eulerian-Eulerian approach to describe drilling fluids as a binary-phase system, including particles in suspension in the non-Newtonian fluid, our research investigates the power-law and Herschel-Bulkley rheological models. These models successfully predict the flow pattern of drilling fluid at the bottom region of deep drilling operations. The study further explores filter-cake formation by examining the influence of overbalanced pressure on filter-cake thickness at various pressures. Drilling simulations, incorporating pipe rotation and eccentricity effects under realistic operating parameters, accurately project filter-cake thickness, aligning closely with experimental measurements and existing CFD literature in this domain.

A method for determining the rheological properties of viscoplastic fluids using a rectangular die

This study introduces a method for determining the rheological parameters of viscoplastic fluids with the use of rectangular dies. The relationship between the wall shear rate and the wall shear stress is investigated for the Casson, Herschel-Bulkley, and Robertson-Stiff rheological models, using two geometric constants for non-circular dies with a regular cross-section. Then, the rheological behavior and parameters of a collagen material were examined by an analytical method and by the proposed approximate method, using experimental data obtained by a slit viscometer and a rectangular die. The yield stress value of the collagen was determined employing the pressure relaxation method. The values were 2940 (±209) Pa from the slit viscometer and 3100 Pa (± 200) Pa from the rectangular die. The rheological parameters of collagen were then obtained using the analytical method and the proposed approximate methods for Casson, Herschel-Bulkley, and Robertson-Stiff rheological models. It was shown that the wall shear rate and the wall shear stress values of the analytical method and the proposed method are in good agreement. It was found that the Herschel-Bulkley and Robertson-Stiff models successfully fitted the wall shear rate-wall shear stress curves with a coefficient of determination equal to or greater than 0.97, and the evaluated consistency values were 165 (±71) Pa.sn for the Herschel-Bulkley model and 947 (±225) Pa.sn for the Robertson-Stiff model, and the flow index values were found to be 0.50 (±0.06) for the Herschel-Bulkley model and 0.32 (±0.03) for the Robertson-Stiff model. However, it was shown that the Casson model is not suitable for describing the rheological characteristic of collagen material. Experimentally obtained parameters for the Herschel-Bulkley model were validated with the use of simulations, and it was found that the numerically and experimentally evaluated results showed good agreement. The maximum deviation was found to be less than 12%.

Study of Magnetorheological Grease’s Thermomagnetic Coupling Rheology

The controllable rheological properties of magnetorheological grease offer significant application prospects in regulating the lubrication behavior of frictional substrates. A novel nano-magnetorheological grease was prepared using nanoscale manganese ferrite as magnetic particles. The prepared magnetorheological grease underwent magnetic field scanning and rate scanning studies under thermomagnetic coupling, and we investigated the variation patterns of rheological parameters under different temperatures and magnetic field intensities. The Herschel–Bulkley rheological model was utilized for data fitting to determine the shear yield stress of the magnetorheological grease. Furthermore, the variation patterns of shear yield stress with increasing magnetic field intensity were explored. The results demonstrated that the apparent viscosity and shear stress of the magnetorheological grease decreased with increasing temperature, while they increased with enhanced magnetic field intensity. The apparent viscosity of the magnetorheological grease decreased with increasing shear rate. Additionally, the shear yield stress of the magnetorheological grease decreased with a temperature rise, but increased when an external magnetic field was applied. The adverse effects of high temperature on the magnetorheological grease could be mitigated by the application of an external magnetic field.

A new pressure gradient model of slurry shield pipeline system coupling with rheological properties and wall slip behaviour under sandy stratum

Pipeline transport is of uttermost importance during slurry shield tunneling, and the precise calculation of the pressure gradient of the pipeline system is the premise for the optimal design of industrial slurry pipeline system. This paper proposed a new muck slurry pressure gradient model of slurry shield pipeline system coupling with the wall slip behaviour based on the Herschel-Bulkley rheological model (H-B model) to estimate the pressure gradient of the muck slurry under sandy stratum. Effects of the sands volume fraction and average particle size on the rheological properties of the muck slurry in pipeline system were investigated to construct the H-B rheological parameters prediction models, which were coupled into the proposed pressure gradient model. Besides, the accuracy and dependability of the proposed model were validated through the engineering field tests and model tests, and the prediction results of the proposed pressure gradient model has an average error of 10.6% and 8.2% with engineering field test data and model test data respectively. The results indicated that the muck slurry is a typical thixotropic fluid. The sand volume fraction and particle size both significantly affect the rheological properties of the muck slurry, the yield stress and plastic viscosity of H-B rheological parameters increase exponentially with the sand volume fraction increasing and increase linearly with the average particle size increasing, the power law index of H-B rheological parameters increases linearly as average particle size and sands volume fraction increase. Ultimately, the research results can provide reasonable suggestions and references for the designing of pipeline system and efficient tunneling of slurry shield.

Gas Helicity Yields New Insights into Gas–Liquid Reactor Design: Enhanced Oxygen Transfer Rate of Coaxial Mixers at Low-Speed Ratio

The gas helicity isosurface plots (i.e., the projection of the gas velocity onto the gas vorticity) were used to visualize the degree of gas entrainment in the impeller vortices. We discovered an interesting link between the gas helicity and the volumetric mass transfer coefficient. The gas helicity can be negatively or positively depending upon the alignment of the entrained gas motion with the impeller rotation. The 1 wt % CMC and xanthan gum solutions obey the power-law and Herschel-Bulkley rheological models, respectively. The dissolved oxygen concentration profile was investigated both experimentally and numerically using coaxial mixers consisting of a central impeller and a wall-scraping anchor. The local gas helicity near the impeller blades revealed that the 1 wt % CMC and xanthan gum solutions experienced a different mass transfer capacity at the critical anchor impeller speed of 30 rpm. This study provides insights into how new energy-efficient impellers can be designed.

Determination of Rheological Parameters of Non-Newtonian Fluids on an Example of Biogas Plant Substrates

Non-Newtonian fluids are commonly used in a wide range of industries; one example are in biogas power plants. Proper measurements and modeling of such fluids can be crucial from the design and operations point of view. Results presented in this study covered seven samples from three plants (a sewage sludge treatment plant, utilization biogas station and a biogas plant in a sugar factory), including mechanically thickened excessive activated sludge (MTEAS), sugar beet pulp (SBP), liquid fruit and vegetable waste (FVW), beet roots (BR) and corn waste (CW); their mixtures were prepared as in a real plant. The total solid content remained below 6.8% for all samples. The apparent viscosity (15 RPM) did not exceed 10 Pas in any sample. A correlation analysis for solvent type influence on the viscosity was carried out. The obtained results were analyzed, and the Herschel–Bulkley rheological model was selected for the fluid description. Then, the Moullinex method was applied to determine the H–B model parameters. The obtained results may contribute to the proper design and operation of various biogas power plants, in which viscosity seems to be one of the crucial flow parameters that influences the device types used, as well as energy consumption.

Avaliação de formulações de taxa de deformação através de escoamentos permanentes e uniformes de fluidos não-Newtonianos no contexto de equações de águas rasas

ABSTRACT Non-Newtonian rheology effects, such as pseudoplasticity and viscoplasticity, are understood as shear stresses, incorporated to the energy slope term in the Shallow-Water Equations (SWE). However, non-Newtonian shear stresses are dependent of the shear rate, whose formulation is a function of the gradient of the velocity profile in the bottom. This study investigated two shear rate formulations that are commonly applied in the SWE literature: 1) a non-parameterized function; and 2) a function based on the Herschel-Bulkley rheological model. Their influence in steady uniform flows of non-Newtonian fluids was evaluated through numerical-theoretical comparisons. A Lax-Friedrichs scheme was implemented to solve the SWE system and allowed employing the shear rate formulations. Experimental tests were carried out and numerical simulations of hypothetical scenarios were performed. It was found that the non-parameterized formulation presented deviation in normal depth up to 14% in comparison with theoretical solution, while the formulation based on the Herschel-Bulkley model provided a good agreement, corroborated by punctual Computational Fluid Dynamics simulations (deviation less than 2%) and experimental data. The ratio of both shear rate formulations is strongly correlated to the deviation of normal depth, indicating that the non-parameterized shear rate function does not provide an acceptable result in the steady uniform flow.

An Approximate Method for Predicting the Friction Factor of Viscoplastic Shear-Thinning Fluids in Non-Circular Channels of Regular Cross-Sections.

The objective of this study is to provide a straightforward generalized simple and quick method for the prediction of the friction factor for fully developed laminar flow of viscoplastic shear-thinning fluids in non-circular channels of regular cross-sections. The most frequently represented substances processed under these conditions are polymers in the processing and plastics industry. A generalized approximate method was proposed to express the relationship between the friction factor and the Reynolds number for the Herschel-Bulkley rheological model. This method uses the generalized Reynolds number for power-law fluids. Moreover, an additional simplified method for rapid engineering calculations was obtained as well. The suggested method was verified by comparing experimental data for concentric annulus found in the literature and results from simulations for concentric annulus, rectangular, square duct with a central cylindrical core and elliptical cross-sections. The results showed that the suggested methods enable us to estimate the friction factor with high accuracy for the investigated geometries.

Study on cavern evolution and performance of three mixers in agitation of yield-pseudoplastic fluids

The hydrodynamic performance of three mixers (single shaft central mixer (SSC), single shaft off-centred mixer (SSO), dual shaft off-centred mixer (DSO), was investigated in the mixing of yield-pseudoplastic fluids (xanthan gum solutions) in the laminar regime. To explore and determine the efficiency of three mixers, both numerical and experimental approaches were adopted. The fluid rheology was described by the Herschel–Bulkley rheological model. Computational fluid dynamics was employed to simulate the apparent viscosity distribution, mixing time, and the flow pattern inside the stirred tank. The developed model was validated through experimentally measured torque. The influence mechanism of the rotational speed and fluid rheology on the cavern evolution was explored deeply. The performances of three mixers in this work were compared at the constant power input and fluid rheology with respect to the flow pattern, mixing time, and mixing efficiency. The results verify that the faster the rotating speed, the greater influence of the fluid rheology on the cavern evolution, and the more uniform apparent viscosity distribution. Moreover, the mixing time decreases continuously as the increasing power consumption per unit volume, and the dimensionless mixing time of DSO mixer was nearly 42.8% and 6.1% shorter than that of SSC and SCO mixer at the same Reynolds number, respectively. According to the mixing efficiency criteria, these data also revealed that DSO was more efficient than SSC and SSO.

Formulation of novel ecofriendly microemulsion-based drilling fluids for improving rheological and filtration characteristics

The main objective of this work was to formulate not environmentally harmful drilling fluids obtained from microemulsion systems, using an aqueous phase (water-glycerol solution 1:1), an oil phase (pine vegetable oil), and varying nonionic surfactants (Tween 80, nonylphenol ethoxylates 100 and 150). Two types of clays (filtration control) were used in the formulation of fluids, Brasgel PA and Cloisite 20 A, in the presence of a viscosifier (xanthan gum), a weighting agent (baritine), a sealant (calcite), and dispersant (water). Properties such as mass loss, filtrate volume, and rheological characteristics of the formulated fluids were analyzed since these are considered essential characteristics for a successful drilling operation. Shear stress (τ) versus shear rate (s−1) data of fluids was best fitted to the Herschel-Bulkley rheological model with R2 of 0.99. The fluids formulated with Brasgel PA obtained the lowest consistency index (k), ranging from 0.37 to 0.61, and, therefore, the force required to start the flow (τy). The thermogravimetric analysis verified that the microemulsified drilling fluids obtained can operate at temperatures up to 100 °C, making it possible to apply them in oil wells with these thermal characteristics. The fluids' filtrate loss volume varied from 2.4 mL to 4.0 mL; the maximum filtercake thickness measured 0.80 mm, and low permeability (0.0173 mD). The analyzed drilling fluids showed a significant swelling reduction when formulated with the microemulsion systems and improved lubricity. In general, it was observed that ecofriendly microemulsion-based drilling fluids were efficient in reducing swelling, showing good rheological and reduced API filtrate loss, being viable alternatives for use in drilling operations of oil wells.

Production of synbiotic Doogh enriched with Plantago psyllium mucilage.

Physical instability and loss of viability of probiotic bacteria are the most important problems in production of synbiotic Doogh. Some plant hydrocolloids have been recognised as effective components to prevent these problems. In this study the effect of Plantago psyllium mucilage (PPM) (0, 0.15%, 0.30%, 0.75% (w/w) on the physicochemical, microbial, and sensory properties of Doogh samples was evaluated by measuring phase separation, viscosity, flow behaviour, probiotic viability and sensory parameters. The results revealed that the stability of samples containing PPM were higher than samples without this hydrocolloid. By increasing the amounts of PPM, the viscosity of treated samples were increased compared to control sample. Herschel-Bulkley rheological model was an appropriate model for describing the flow behavior of Doogh formulated with PPM and the power-law rheological model was suitable model for describing the flow behavior of control samples. PPM had non-digestible food ingredients and improved the viability of Lactobacillus casei; therefore, this herbal mucilage may have prebiotic potential. Finally, the samples treated with 0.30% PPM on the 15th day were chosen as the best formulation for the production.

Study on the Formation Characteristics of CO2 Hydrate and the Rheological Properties of Slurry in a Flow System Containing Surfactants.

Adding low dosage hydrate inhibitors to the hydrate systems makes the generated hydrate particles more uniformly dispersed in the liquid phase, which can significantly reduce the hydrate accumulation and blockage in oil and gas pipelines. The effect of surfactant hydrophile–lipophilic balance (HLB) values on hydrate flow characteristics was studied with a flow loop. The experimental results showed that there was a critical HLB value. When the HLB value was 4.3–9.2, it had an inhibitory effect on the hydrate induction time, and when the HLB value was greater than 10.2, it had a promoting effect. The hydrate volume fraction increased gradually with the increase in the HLB value, while the slurry apparent viscosity decreased with the increase in the HLB value. It was also found that different types of surfactants all showed the effects of anti-agglomerant and dispersion, which can obviously improve the flow of the hydrate slurry. Finally, the analyzed results showed that the hydrate slurry exhibited shear-thinning behaviors that can be identified as a pseudoplastic fluid based on the Herschel–Bulkley rheological model, and the functional relationship between the rheological index and the solid phase hydrate volume fraction was obtained using the fitting method. This study can provide a reference for the preparation of high-efficiency hydrate anti-agglomerants.

Development of the algorithm for calculating the optimal molding modes of the BeO slurry using various rheological models

This paper presents the results of calculating a mathematical model of the flow and heat transfer of thermoplastic beryllium oxide in a round channel of a molding installation. An algorithm for calculating the system of equations based on the Herschel-Bulkley rheological model has been developed. The finite-difference analogue of the equations system of motion, continuity, and energy is solved numerically using the CrankNicholson difference scheme. The three-parameter equation is used to test the consistency of experimental, data, and how adequately the physical features of the non-isothermal flow of the slurry convey comparing to the Shvedov-Bingham model. The calculation results illustrate that the proposed model reflects the most important features of the thixotropic flow character of the slurry and is in better agreement with the experimental data of viscoplastic fluids. It provides the calculations of speed of viscous-plastic flow of the slurry based on Shvedov-Bingham and Herschel Bulkley’s two rheological models considering the peculiarities of coagulation structure formation and flow mechanism with boundary conditions. As a result of calculations, the fields of velocity, temperature, and density were obtained, which describe the regularities of the flow and heat transfer of a thermoplastic slurry. The change in the Nusselt criterion along the length of the shaping cavity is shown, which coincides with the analytical solution of Nusselt under first kind boundary conditions. The optimal conditions for the process of ceramics molding by hot casting method have been found, allowing to obtain a hardened product with a homogeneous structure of beryllium ceramics at the outlet.

Effect on rheology and frying stability of edible oil before and after addition of fenugreek seeds

Rheological parameters of vegetable oils showed great changes during frying. The correlation between rheological behavior and viscosity measurements during frying can give a good overall estimate of frying oil quality. In the present study, rheological properties of rice bran oil (RBO) and soybean oil (SBO) during deep-frying of 13 ​min were investigated for consecutive 1st, 2nd, 3rd, and 4th frying at an interval of one week. To enhance the frying stability of RBO and SBO, fenugreek seeds (Trigonellafoenum graecum) was added during frying. The shear stress versus shear rate data was fitted to Newtonian and Herschel-Bulkley rheological models. The flow behavior of RBO and SBO with and without fenugreek seeds in before and after frying were measured at 30 ​± ​2 ​°C. The increase in viscosity, acid values and flow behavior index (n) with frying times for both RBO and SBO can be controlled with the addition of fenugreek seed up to 3rd frying with n ​< ​1 values, where without fenugreek seeds for RBO and SBO it showed a shear thickening properties (n ​> ​1) after 2nd and 3rd frying respectively.

Rheology of three-phase suspensions determined via dam-break experiments.

Three-phase suspensions, of liquid that suspends dispersed solid particles and gas bubbles, are common in both natural and industrial settings. Their rheology is poorly constrained, particularly for high total suspended fractions (≳0.5). We use a dam-break consistometer to characterize the rheology of suspensions of (Newtonian) corn syrup, plastic particles and CO2 bubbles. The study is motivated by a desire to understand the rheology of magma and lava. Our experiments are scaled to the volcanic system: they are conducted in the non-Brownian, non-inertial regime; bubble capillary number is varied across unity; and bubble and particle fractions are 0 ≤ ϕ gas ≤ 0.82 and 0 ≤ ϕ solid ≤ 0.37, respectively. We measure flow-front velocity and invert for a Herschel-Bulkley rheology model as a function of , , and the capillary number. We find a stronger increase in relative viscosity with increasing in the low to intermediate capillary number regime than predicted by existing theory, and find both shear-thinning and shear-thickening effects, depending on the capillary number. We apply our model to the existing community code for lava flow emplacement, PyFLOWGO, and predict increased viscosity and decreased velocity compared with current rheological models, suggesting existing models may not adequately account for the role of bubbles in stiffening lavas.

A radial hydraulic fracture driven by a Herschel–Bulkley fluid

We analyse the influence of fluid yield stress on the propagation of a radial (penny-shaped) hydraulic fracture in a permeable reservoir. In particular, the Herschel–Bulkley rheological model is adopted that includes yield stress and non-linearity of the shear stress. The rock is assumed to be linear elastic, and the fracture is driven by the point source fluid injection with a constant volumetric rate. The fracture propagation condition follows the theory of linear elastic fracture mechanics, and Carter’s leak-off law is selected to govern the fluid exchange process between the fracture and formation. The numerical solution of the problem is found using the algorithm based on Gauss–Chebyshev quadrature and Barycentric Lagrange interpolation techniques. We also construct an approximate solution with the help of the global fluid balance equation and the near-tip region asymptote. The latter approximation is computationally efficient, and we estimate its accuracy by comparing the primary crack characteristics such as opening, pressure, and radius with those provided by the full numerical solution. We present examples corresponding to typical field cases and demonstrate that the addition of yield stress can lead to a shorter radius and wider opening compared to the corresponding case with simpler power-law fluid rheology. Further, we quantify the limiting propagation regimes (or vertex solutions) characterised by the dominance of a particular physical phenomenon. Relative to the power-law results, there are two new vertices that are associated with the domination of yield stress: storage-yield-stress and leak-off-yield-stress. To understand the influence of various problem parameters, we utilise the constructed approximate solution to investigate the dimensionless parametric space of the problem, in which the applicability domains of the limiting solutions are quantified. This enables one to quickly determine whether yield stress provides a strong influence for given problem parameters. • Analysis of the impact of fluid yield stress on radial fracture propagation. • Comparison with the power-law rheological model. • Numerical and rapid semi-analytical approximate solutions for the problem. • Construction of the dimensionless parameter space for the problem. • Quantitative identification of parameters for which yield stress is important.

Development and Rheological Evaluation of DEET (N,N-DiethyL-3-Methylbenzamide) Microparticles Loaded Hydrogel For Topical Application

N,N-Diethyl-3-methylbenzamide (DEET) is a broad-spectrum insect repellent that can easily permeate through the skin and can cause undesirable effects, especially in children and pregnant women. The objective of this research was to formulate and evaluate DEET-encapsulated microparticles containing a hydrogel designed to reduce skin permeation and prolong drug release. The formulation design was based on the independent formulation variables of the concentration of chitosan and sodium tripolyphosphate using a simple factorial design experiment. DEET-loaded microparticles were developed and incorporated into a hydrogel. The size of the microparticles was analyzed using the Zetasizer Nano® particle size analyzer, and the surface morphology, using field emission scanning electron microscopy. Drug release from the microparticles was determined by the dialysis bag method. A rheological evaluation of the formulated gel was performed using a Thermo Haake Rheometer. The in vitro permeation of the formulation was performed using a synthetic Strat-M® membrane. The size of the microparticles ranged from 0.45 to 8.3 μm, and the encapsulation efficiencies were >50% for all the formulations. The drug-release curves showed no initial burst release from the microparticle formulation. Instead, a slow and controlled drug release was observed over 24 hours that followed Higuchi kinetics. The cumulative amount of DEET permeated (over 24 h) from the DEET solution (control), and the formulation was 211.6±19.5 μg/cm2 and 4.07±0.08 μg/cm2, respectively. A significantly low DEET permeation from the microparticle formulations indicated minimal absorption of the drug into the body and thus, reduced systemic toxicity. Thixotropic evaluation of the hydrogel formulation demonstrated a hysteresis loop that fitted closely to the Herschel-Bulkley rheological model, ensuring an effortless application and prolonged retention on the skin. Hence, it can be concluded that the developed formulation is an effective delivery approach for controlled insect repellent activity with reduced skin absorption.

Fe3O4-CMC nanocomposite performance evaluation as rheology modifier and fluid loss control characteristic additives in water-based drilling fluid

In drilling operations, there has been a considerable amount of attention to the drilling fluid formulation and characteristics. In recent years, the utilization of nanocomposite as an additive exhibited a promising improvement in the water-based drilling fluid rheological properties. The conventional additives have a lot of deficiencies such as being expensive, complicated synthesis methods, and not having desirable rheology properties. To eliminate the deficiencies, an investigation on the efficacy of Fe 3 O 4 - carboxymethyl cellulose (CMC) nanocomposite on the rheological and filtration characteristics as an additive in the water-based drilling fluid are carried out in this study. The nanocomposite was synthesized by the co-precipitation method and Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and energy dispersive x-ray was employed for characterization. Then, the nanocomposite with different ratio was utilized as an additive to drilling fluid and the rheological and filtration properties of fluid was measured for both deionized water and salty water. The results show that by adding 57% of 1:3 Fe 3 O 4 -CMC nanocomposite ratio to basic drilling fluid, in addition to considerable improvement in the viscosity, the filtration volume and cake thickness decreased noticeably. This formulation depicts non-Newtonian rheological behavior which could be illustrated properly by Herschel–Bulkley rheological model. Thus, exploitation of Fe 3 O 4 -CMC nanocomposite as an additive in water-based drilling fluid for fluid loss control would have advantageous due to its distinctive properties like enhanced resistance to water penetration and enhanced viscosity in both deionized water and salty water. In addition, the Fe 3 O 4 -CMC nanocomposite has superior properties such as uncomplicated synthesis method and being financially available in comparison to conventional additives. • Fe 3 O 4 -CMC Nanocomposite was synthesized by co-precipitation method. • Fe 3 O 4 -CMC Nanocomposite significantly decreased fluid loss and filter cake thickness of water-based drilling fluid. • Fe 3 O 4 -CMC Nanocomposite considerably enhanced the viscosity of water-based drilling fluid. • Fe 3 O 4 -CMC Nanocomposite caused a uniformed filter cake. • Fe 3 O 4 -CMC Nanocomposite exhibited better properties than pure CMC, while less CMC proportion was utilized.

Hole-Cleaning Fibers Improve Cuttings-Carrying Capacity

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 203147, “Investigating Hole-Cleaning Fibers’ Mechanism To Improve Cutting Carrying Capacity and Comparing Their Effectiveness With Common Polymeric Pills,” by Mohammad Saeed Karimi Rad, Mojtaba Kalhor Mohammadi, SPE, and Kourosh Tahmasbi Nowtarki, International Drilling Fluids, prepared for the 2020 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, held virtually 9–12 November. The paper has not been peer reviewed. Hole cleaning in deviated wells is more challenging than in vertical wells because of the boycott effect or the eccentricity of the drillpipe. Poor hole cleaning can result in problems such as borehole packoff or excessive equivalent circulating density. The complete paper investigates a specialized fibrous material (Fiber 1) for hole-cleaning characteristics. The primary goal is to identify significant mechanisms of hole-cleaning fibers and their merits compared with polymeric high-viscosity pills. Hole-Cleaning Indices Based on a review of the literature, most effective parameters regarding hole cleaning in different well types were investigated. These parameters can be classified into the following five categories: - Well design (e.g., hole angle, drillpipe eccentricity, well trajectory) - Drilling-fluid properties (e.g., gel strength, mud weight) - Formation properties (e.g., lithology, cutting specific gravity, cuttings size and shape) - Hydraulic optimizations (e.g., flow regime, nozzle size, number of nozzles) - Drilling practices (e.g., drillpipe rotation speed, wellbore tortuosity, bit type, rate of penetration, pump rate) In this research, rheological parameters and parameters of the Herschel-Bulkley rheological model are considered to be optimization inputs to increase hole-cleaning efficiency of commonly used pills in drilling operations. The complete paper offers a detailed discussion of both the importance of flow regime and the role of the Herschel-Bulkley rheological model in reaching a better prognosis of drilling-fluid behavior at low shear rates. The properties of the fibrous hole-cleaning agent used in the complete paper are provided in Table 1. Test Method Two series of tests were performed. The medium of the first series is drilling water, with the goal of evaluating the efficiency of Fiber 1 in fresh pills. The second series of tests was per-formed with a simple polymeric mud as a medium common in drilling operations. Formulations and rheological properties of both test series are provided in Tables 4 and 5 of the complete paper, respectively.