Related Experiment Video
Updated: Aug 15, 2026
10:38
Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions
Published on: June 6, 2017
Rheological Yield Behavior of Qinghai Gelled Crude Oil Under Multiple Loading Modes: Creep, Ramp, Step, and
Mingzhen Lin1,2,3, Jia Shi1, Yidan Feng1
1School of Petroleum Engineering, Shandong Institute of Petroleum and Chemical Technology, Dongying, Shandong 257061, China.
ACS Omega
|August 14, 2026
Summary
This study reveals the complex rheological yield behavior of waxy crude oil under various loading conditions. A new nonlinear creep model accurately predicts the complete creep process for gelled crude oil.
Area of Science:
- Petroleum Engineering
- Materials Science
Background:
- Waxy crude oil exhibits complex rheological properties, particularly gelled states.
- Understanding yield behavior is crucial for efficient oil extraction and transportation.
Purpose of the Study:
- To investigate the rheological yield behavior of Qinghai gelled crude oil under multiple loading modes.
- To develop a comprehensive model for predicting creep behavior.
Main Methods:
- Experimental investigation of rheological yield under constant stress, linearly increasing shear stress, stepwise increasing shear stress, and continuously increasing shear rates.
- Development of a nonlinear creep equation incorporating damage variables and hardening functions.
Main Results:
- Under constant stress, a three-stage creep process (decelerating, steady-state, accelerating) was observed.
- Yield stress and yield time showed distinct dependencies on loading rate, stage duration, and stress increments.
- A developed nonlinear creep model accurately described the complete creep behavior without piecewise treatment.
Conclusions:
- The rheological yield behavior of waxy crude oil is highly sensitive to loading conditions.
- The developed nonlinear creep model offers a robust approach to characterizing waxy crude oil flow.
- Findings provide valuable insights for optimizing the handling and processing of waxy crude oil.
Related Concept Videos
01:21Plastic Behavior
A material's elastic behavior is characterized by the disappearance of stress once the load is removed, allowing the material to return to its original state. However, when stress surpasses the yield point, yielding commences, marking the onset of plastic deformation or permanent set. This change from elastic to plastic behavior is influenced by the peak stress value and the duration before the load is removed. An intriguing observation occurs when a specimen is loaded, unloaded, and reloaded.
01:24Stress-Strain Diagram - Ductile Materials
The stress-strain relationship in ductile materials such as structural steel or aluminium is intricate and progresses through several stages. When a specimen is loaded, it initially exhibits a linear length increase, depicted by a steep straight line on the stress-strain diagram. It indicates the material is elastically deforming and will return to its original shape once unloaded. However, when a critical stress value is reached, plastic deformation begins. This stage sees substantial...
01:20Plastic Deformation in Circular Shafts
When materials are subjected to forces that surpass their yield strength, they undergo a process known as plastic deformation. This results in a permanent alteration or strain in their structure. This concept can be specifically applied to circular shafts, where the deformation leads to a change in its shape. The precise evaluation of this plastic deformation requires understanding the stress distribution within the circular shaft, which is achieved by calculating the maximum shearing stress in...
01:20Shearing Strain
The shearing strain represents a cubic element's angular change when subjected to shearing stress. This type of stress can transform a cube into an oblique parallelepiped without influencing normal strains. The cubic element experiences a significant transformation when exposed solely to shearing stress. Its shape alters from a perfect cube into a rhomboid, clearly demonstrating the effect of shearing strain. The degree of this strain is considered positive if it reduces the angle between the...
01:25Yield Criteria for Ductile Materials under Plane Stress
In designing structural elements and machine parts using ductile materials, it is crucial to ensure that these components withstand applied stresses without yielding. Yielding is initially determined through a tensile test, which evaluates the material's response to uniaxial stress. However, tensile stress is insufficient when components face biaxial or plane stress conditions This condition requires advanced criteria to predict failure.
The Maximum Shearing Stress Criterion, also known as the...
The Maximum Shearing Stress Criterion, also known as the...
01:19Viscosity of Fluid
Viscosity measures the resistance a fluid offers to flow and deformation. It results from internal friction between layers of fluid moving relative to one another. Dynamic viscosity, denoted by the Greek letter mu (μ), quantifies the force needed to move one fluid layer over another. For Newtonian fluids like water and air, the relationship between the shearing stress and the rate of shearing strain is linear, meaning their viscosity remains constant regardless of the applied stress.