Crude oil yield stress
The yield strength of waxy crude oil gel has been characterized by many within the literature , , , , , , , , amongst others. As documented, the yield stress can be measured via various experimental protocols; the creep-recovery test, the oscillatory test, the stress ramp test and many more. Waxy crude oils are likely to develop a yield stress when cooled to a temperature below its wax appearance temperature. In a subsea pipeline, when the flow stops and the oil cools down, a minimum differential pressure is required to restart the flow. YIELD STRESS IN WAXY CRUDE OIL EMULSIONS. Waxy crude oil is a very complex non-Newtonian material, which exhibits time-dependence related to vis-coelasticity and thixotropy. In addition, such material is rather dependent to the temperature history, which turns the measurements of the rheological properties rather difficult. Guided by a series of discriminating rheometric tests, we develop a new constitutive model that can quantitatively predict the key rheological features of waxy crude oils. We first develop a series of model crude oils, which are characterized by a complex thixotropic and yielding behavior that strongly depends on the shear history of the sample. yield stress s y varies in the gelled crude oil (especially when aging processes and shear history cause large variations of s y with time). This necessitates a constitutive law that can be both fit to rheological data, and has predictive capabilities. A more comprehensive approach to the rheology of elasto-
The effect of the thermal history on the waxy structure of two statically cooled waxy crude oils is examined using a controlled stress rheometer for rheological measurements and a microscope to
The literature has shown that not only the temperature itself but also the fluid shear and thermal histories have significant influence on the yield stress of waxy crude oils. This paper investigates the effect of the initial cooling temperature on the waxy crude oil viscosity, gelation temperature, and yield stress. waxy crude oil gels. One feature of waxy crude oil gels that complicates the experimental characterization, is the dependency of yield stress and gel breakdown not only on the actual temperature (and pressure), but also on the thermal and shear history prior to the measurement conditions5,11. This has its origin in a complex interplay of various Main article: Oil processing Crude oil is a liquid extracted by pumpjacks from oil fields and can be converted to petroleum gas, light oil, and heavy oil by an oil refinery.It can be transported either in pipes, barrels or fluid wagons.. It can also be used as ammo in flamethrower turrets.. Oil fields. Oil fields can be used indefinitely, but the amount they yield will reduce over time. This study is intended to propose a systematic protocol to determine the geometry gap settings for better repeatability of the yield stress measurements of gelled waxy crude oils. The reliability Waxy crude oils are likely to develop a yield stress when cooled to a temperature below its wax appearance temperature. In a subsea pipeline, when the flow stops and the oil cools down, a minimum differential pressure is required to restart the flow. The yield stress of a waxy crude oil is not only dependent on the oil composition, such as wax content, wax type, and the amounts of asphaltenes and resins, but it is also influenced by the thermal and shear history (Paso, 2014, Paso et al., 2009), as well as the measurement conditions.
Influence of the initial cooling temperature on the gelation and yield stress of waxy crude oils. Abstract. One of the major problems in waxy crude oil production
The yield strength of waxy crude oil gel has been characterized by many within the literature , , , , , , , , amongst others. As documented, the yield stress can be measured via various experimental protocols; the creep-recovery test, the oscillatory test, the stress ramp test and many more. Waxy crude oils are likely to develop a yield stress when cooled to a temperature below its wax appearance temperature. In a subsea pipeline, when the flow stops and the oil cools down, a minimum differential pressure is required to restart the flow. YIELD STRESS IN WAXY CRUDE OIL EMULSIONS. Waxy crude oil is a very complex non-Newtonian material, which exhibits time-dependence related to vis-coelasticity and thixotropy. In addition, such material is rather dependent to the temperature history, which turns the measurements of the rheological properties rather difficult.
Waxy crude oils are likely to develop a yield stress when cooled to a temperature below its wax appearance temperature. In a subsea pipeline, when the flow stops and the oil cools down, a minimum differential pressure is required to restart the flow. In order to estimate that pressure, it is crucial knowing the yield stress distribution in the pipe at restart time.
18 Jan 2018 It was clear that the heavy crude oil required a yield stress of 0.7 Pa, whereas it did not require any yield stress to pump the heavy crude oil-light The yield stress measurements were determined from the relationship between shear stress and shear rate valued measured using Brookfield viscometer. Oil 25 Jun 2009 Their effects on the rheological property (yield stress) and crystallization behaviors of both model waxy oils and crude oils were observed by 10 Feb 2018 The apparent yield stresses for Alcoflood aqueous solutions and their crude oil emulsions are increased by polymer concentration. Higher. with σ being the stress, σy the yield stress and crude oils, concrete, etc. is that the yield stress of a To improve the flow ability of crude oil with high content of aromatic Upon the addition of MASCs, the yield stresses of oils were decreased by 1 to 3 orders of
Yield stress is the rheological property that determines the strength of the waxy crude oil. The knowledge of the yield stress is crucial in estimating the force required for pigging the waxy crude oil or the pressure needed to restart the completely clogged oil pipelines.
Abstract Break Away Yield Stress (BAYS) has been measured on waxy crude oil from the South China Sea to help develop appropriate design specifications for Yield Stress Measurement and Thixotropic Behaviour of Waxy Crude Oil from the Malay Basin. This article's rating: (Average from 0 ratings). Combined technical.
The stress that must be applied to a material to make it begin to flow (or to yield). Yield stress is a parameter in the Herschel-Bulkley rheological model. The yielding behavior of the wax-oil gels gives an insight of critical yield stress useful in pipeline restart. Wax-oil gels never yields at low stress whereas fractures 31 Dec 1996 Abstract. Break Away Yield Stress (BAYS) has been measured on waxy crude oil from the South China Sea to help develop appropriate design