Herschel–Bulkley fluid

About: Herschel–Bulkley fluid is a research topic. Over the lifetime, 1946 publications have been published within this topic receiving 49318 citations.

Creeping flow of generalized Newtonian fluid through a fixed and a fluidized bed of spherical particles

Abstract: The modified Rabinowitsch-Mooney equation, together with the corresponding relations for consistency variables has been employed to the flow solution of generalized Newtonian fluid through a fixed and a fluidized bed of spherical particles. The usefulness of the proposed equations has been verified for a power-law fluid, using both the published and original experimental results

Exact Solutions for the Axial Couette Flow of a Fractional Maxwell Fluid in an Annulus

Abstract: The velocity field and the adequate shear stress corresponding to the rotational flow of a fractional Maxwell fluid, between two infinite coaxial circular cylinders, are determined by applying the Laplace and finite Hankel transforms. The solutions that have been obtained are presented in terms of generalized 𝐺𝑎,𝑏,𝑐(⋅,𝑡) and 𝑅𝑎,𝑏(⋅,𝑡) functions. Moreover, these solutions satisfy both the governing differential equations and all imposed initial and boundary conditions. The corresponding solutions for ordinary Maxwell and Newtonian fluids are obtained as limiting cases of our general solutions. Finally, the influence of the material parameters on the velocity and shear stress of the fluid is analyzed by graphical illustrations.

Rheological Evaluations of CO2 Miscible Hydrocarbon Fracturing Fluids

Abstract: Previous publications (1-4) described the theory and application of CO 2 miscible hydrocarbon fracturing fluids to gas well stimulation. The fluids are ideally suited to gas reservoirs susceptible to phase trapping due to high capillary pressures when water-based fluids are used. Reservoirs particularly prone to phase trapping are those with low permeability (less than 0.1 md), those that are subnormally water-saturated, and those that are under pressured. In order to conduct meaningful rheological evaluations for determination of fluid properties and required chemical concentrations, it is essential that downhole conditions be accurately duplicated. The most fundamental requirement is that the gelled hydrocarbon and liquid CO 2 be combined and homogenized below the critical temperature of CO 2 (31° C) and at a pressure above the bubble point of the resulting fluid mixture to ensure one miscible phase. This normally requires a minimum initial pressure of at least 20 MPa. Temperature is increased to the bottomhole static temperature of the well under consideration as the test progresses. This requires that the rheometer have a pressure rating high enough to withstand the increased pressure caused by expansion. This paper presents several different testing methodologies designed to provide representative rheology vs. time with all chemicals present, and to provide varying insights into fluid behaviour. The first utilizes a conventional bob and sleeve configuration in a heated pressure chamber rated to 102 MPa and 204° C (5) . This allows one to gather shear stress vs. shear rate data as a function of time. Normal Power Law n' and k' parameters are calculated and are in turn used to calculate apparent viscosity vs. time. Secondary mixing is provided by a helical fin attached to the outside of the sleeve, which creates a rotational flow pattern in the rheometer. The second methodology utilizes a capillary tube viscometer allowing for precise and accurate control of the shear rate. The capillary tubes used are capable of 68 MPa at 204° C and are sized according to the expected viscosity range and range of desired shear rates. The fluid of interest is displaced through the tube using a push-pull system of two positive displacement syringe (Ruska) pumpsone in injection and one in extraction mode to keep the system pressure at the desired level. Varying the injection rate allows one to vary the shear rate as desired. Shear stress vs. shear rate data are collected as a function of time, again allowing normal power law parameters as well as apparent viscosity to be calculated. The third methodology uses an oscillating (sinusoidal) strain. The resulting stress has an elastic component and a viscous component. G' is the elastic component and can be thought of like a spring constant. A Newtonian liquid has no storage modulus (G'). Elastic behaviour is important for suspending proppant at low shear rates. This methodology therefore provides insights into fluid behaviour that complement those obtained using shear stress vs. shear rate measurements.

Evaluation of the Behavioral Characteristics in a Gas and Heavy Oil Stratified Flow According to the Herschel–Bulkley Fluid Model

Abstract: At present, most researches on gas-liquid two-phase flow use a power-law fluid model. However, with the development of unconventional petroleum resources and the restarting of heavy oil, the fluid showed strong yield characteristics. The power-law constitutive will not be able to express the yield-pseudoplastic fluid rheological properties. In order to make the study applicable to a larger range of shear rates, this study used the Herschel-Bulkley fluid model to discuss the gas-liquid flow characteristics. Based on the Herschel-Bulkley fluid constitutive, a two-fluid model, combined with dimensionless and iterative calculation methods, was used to theoretically derive the prediction model of liquid holdup and pressure drop for gas-liquid stratified flow. The effects of non-Newtonian fluid rheological parameters, flow conditions, and pipeline geometry on Herschel-Bulkley fluid and gas stratified flow were further analyzed. The results show that the power-law index n and the yield stress τ0 (characterizing the rheological characteristics of the liquid phase) have significant effects on the gas-liquid two-phase stratified flow. Specifically, the enhanced liquid yield and shear thinning characteristics will lead to an increase in liquid holdup and a decrease in pressure drop. Comparing with the experimental data, the calculation model proposed in this work has a good prediction effect and provides new insights into the flow behavior of gas and waxy heavy oil with yield stress.

Simple shear flow of a Herschel-Bulkley fluid with wall slip above a threshold stress

Abstract: The simple shear flow of Herschel-Bulkley fluids is analyzed, under the assumption that wall slip occurs at both plates above a characteristic wall shear stress, the slip yield stress. The latter critical value is usually lower than the yield stress of viscoplastic materials exhibiting wall slip. The effects of wall slip and the slip yield stress on the apparent flow curve, i.e. the plot of the shear stress vs the apparent shear rate, are investigated. With non-viscoplastic fluids, the flow curve is gap-independent below the slip yield stress. Above a critical apparent shear rate at which the slip yield stress is exceeded, a plateau zone is encountered, and then the flow curve becomes gap dependent. Viscoplastic materials remain at rest for stresses below the slip yield stress, slide unyielded for stresses between the slip yield stress and the yield stress, at half the velocity of the moving plate, and yield and slip for stresses above the yield stress. Hence, the apparent flow curve exhibits an initial plateau corresponding to slip yield stress, followed by a rapid-growth gap-dependent part and a second plateau corresponding to the yield stress, and then approaches asymptotically its zero-slip-yield-stress counterpart. This behavior describes well certain rheometric experiments on concentrated suspensions and pastes.