Delineating the Pour Point and Gelation Temperature of Waxy Crude Oils

SPE Journal ◽  
2002 ◽  
Vol 7 (04) ◽  
pp. 349-352 ◽  
Author(s):  
Ramachandran Venkatesan ◽  
Probjot Singh ◽  
H. Scott Fogler
Keyword(s):  
Pour Point ◽  
Crude Oils ◽  
Gelation Temperature ◽  
Waxy Crude ◽  
Waxy Crude Oils

scholarly journals THE ELASTO-VISCOPLASTIC-TIME-DEPENDENT NATURE OF WAXY CRUDE OILS

2014 ◽  
Vol 13 (2) ◽  
pp. 16
Author(s):  
B. A. Tarcha ◽  
B. P. P. Forte ◽  
E. J. Soares ◽  
R. L. Thompson
Keyword(s):  
Yield Stress ◽  
Crude Oils ◽  
Time Dependency ◽  
Gelation Temperature ◽  
Viscous Effects ◽  
Waxy Crude Oil ◽  
Waxy Crude ◽  
Crucial Feature ◽  
Waxy Crude Oils

Production in reservoirs located in deep and ultra-deep water that contain waxy crude oils faces a huge obstacle imposed by the low temperatures of the environment. When the waxy crude oil is subjected to a temperature below the Gelation Temperature, as in the case investigated in the present work, it exhibits a variety of non-Newtonian features: elasticity, plasticity, viscous effects, and time-dependency, which renders to this material a highly complex behavior. A crucial feature that is frequently ignored when the determination of the yield stress is being carried out is the timedependency nature of these materials. We demonstrate that this character has a significant impact on the measurement of the yield stress and, therefore, values obtained from a protocol that neglects time-dependency can be substantially different from a more careful procedure.

Experimental Investigation of Rheological Behaviors and Flow Improving by Chemical for Waxy Crude Oils

2006 ◽  
Author(s):  
Jiaqiang Jing ◽  
Zhongyuan Guan ◽  
Xiaoqin Xiong ◽  
Hua Tian ◽  
Liwen Tan
Keyword(s):  
Structure Formation ◽  
Pour Point ◽  
Viscosity Reduction ◽  
Crude Oils ◽  
Polarization Microscopy ◽  
Rheological Behaviors ◽  
Waxy Crude ◽  
Waxy Crude Oils ◽  
Flow Improver ◽  
Wax Crystals

It has been proved that the flow improver makes the transportation of waxy crude oils in pipeline much more economic and safe, but so far an universal flow improver for various waxy crude oils has not been found because of inadequately understanding the action mechanism of the flow improvers. Therefore it is necessary for the mechanism to be studied further. A series of synthetic waxy oils (SWOs) with or without flow improver GY1, a long chain alkyl acrylate polymer based chemical, are prepared from 25# transformer oil, 50#, 60# (macrocrystalline) and 80# (microcrystalline) wax, single or mixed, and in some cases 60# road asphalt by mixing the ingredients at 100°C for 1 hour. Characteristic temperatures, viscosity-temperature properties and rheological behaviors are studied by using rheological techniques, and microstructures of wax crystals grown from SWOs at 20 °C are analyzed by using a polarization microscopy. Some abnormal viscosity-temperature properties of SWOs are found, which mainly results from wax crystallization and network structure formed by wax crystals. The mechanisms involved in the structure formation and fluidity improved by chemical for SWOs are discussed here. Studies show that the structure formation is followed by the formation of crystal nuclei, growth and interconnection or bridging of the wax crystal particles, which is closely relevant to wax molecular dimension and content, crystalline particle size, shape, concentration and surface characteristics. GY1 added into the SWOs lowers their cloud points by 0–2.0 °C and enhances the amounts of wax precipitated at 30 °C by 10–35wt%, which might not be involved in the mechanisms of the fluidity improving under this study. The extent of pour point depression by GY1 increases with increasing the wax molecular size and decreasing the wax content in the SWOs. As long as the SWO treated by GY1 has a greater yield stress reduction at the temperature closed to its pour point, its viscosity and pour point reduction will be more obvious. The common shortcut of pour point depression and viscosity reduction is to inhibit or desintegrate the formation of paraffin crystal network. The mechanisms involved in fluidity improvement of waxy crude oils by chemicals include modifying surface properties of waxy crystals and promoting crystal particle growth with higher symmetry.

PIPELINE FLOW OF WAXY CRUDE OILS

1992 ◽  
Vol 32 (1) ◽  
pp. 405
Author(s):  
L.T. Wardhaugh ◽  
D.V. Boger
Keyword(s):  
Pour Point ◽  
Measurement Techniques ◽  
Design Methods ◽  
Crude Oils ◽  
Newtonian Viscosity ◽  
Waxy Crude ◽  
Laminar And Turbulent Flow ◽  
Waxy Crude Oils ◽  
The University ◽  
Shear History

The various methods for handling waxy crude oils at temperatures below the pour point have been difficult to assess quantitatively owing to the lack of reliable measurement techniques for properties such as the non-Newtonian viscosity and yield stress. Research undertaken at The University of Melbourne has been aimed at the development of reproducible measurement techniques for laboratory scale rheometers and, in so doing, has provided an understanding of the rheology of waxy oils that is applicable to the design and operation of waxy oil pipelines and handling systems and in understanding the startup behaviour of pipelines.The equilibrium flow properties of waxy oils are determined by the shear and thermal history applied to the oil. In particular, the very strong shear history dependence influences the behaviour of pipelines servicing declining fields, leads to an over-estimation of the flowrate when conventional design methods are used, and provides a mechanism for wall deposition of wax that depends on the oil rheology rather than mass transfer mechanisms. Modified design methods are outlined for both laminar and turbulent flow which account for the effect of shear history and enable a quantifiable measure, under steady conditions, of the return on investment of alternative handling techniques such as the use of flow improver additives.Waxy crude oil that has been statically cooled develops solid-like character at temperatures below the pour point. The complex yielding process exhibits three distinct behaviours-yield, creep and fracture, each of which influences the startup behaviour of a gelled pipeline.

LOW TEMPERATURE FLOW CHARACTERISTICS OF SOME WAXY CRUDE OILS IN RELATION TO THEIR COMPOSITION : PART I WITH AND WITHOUT POUR POINT DEPRESSANT ADDITIVES

1997 ◽  
Vol 15 (5-6) ◽  
pp. 495-502 ◽  
Author(s):  
D. Sree Lakshmi ◽  
M. Rama Krishna ◽  
M. Vanketasrrwar Rao ◽  
M. Bhagvanth Rao ◽  
R.C. Purohit ◽  
...  
Keyword(s):  
Low Temperature ◽  
Pour Point ◽  
Flow Characteristics ◽  
Crude Oils ◽  
Pour Point Depressant ◽  
Waxy Crude ◽  
Point Depressant ◽  
Waxy Crude Oils

Research Progress and Discussion of Waxy Crude Pour Point Depressants: A Mini Review

2020 ◽  
Vol 13 (4) ◽  
pp. 323-331
Author(s):  
Zhengnan Sun ◽  
Jing Zhang ◽  
Guolin Jing ◽  
Yang Liu ◽  
Shuo Liu
Keyword(s):  
Crude Oil ◽  
Pour Point ◽  
Three Dimensional ◽  
Research Progress ◽  
Crude Oils ◽  
Waxy Crude ◽  
Main Research ◽  
Oil Exploitation ◽  
Pour Point Depressants ◽  
Waxy Crude Oils

The crude oils exploited in oilfields are mainly high-wax crude oils. Paraffins precipitate, crystallize, and form a three-dimensional network structure, when the temperature falls below the Wax Appearance Temperature (WAT), which decreases crude oil fluidity. This poses huge challenges to oil exploitation and transportation, as well as cost control. To date, the addition of chemical pour point depressants has been a convenient and economical method to improve low-temperature fluidity in crude oils. This article reviews the types of pour point depressants of crude oil and their performance mechanisms, and introduces the main research methods and progress made in the study of the performance mechanisms of pour point depressants in waxy crude oils. Finally, the development direction of pour point depressants is prospected.

Polymeric Wax Inhibitors and Pour Point Depressants for Waxy Crude Oils: A Critical Review

2014 ◽  
Vol 36 (2) ◽  
pp. 213-225 ◽  
Author(s):  
Fei Yang ◽  
Yansong Zhao ◽  
Johan Sjöblom ◽  
Chuanxian Li ◽  
Kristofer G. Paso
Keyword(s):  
Critical Review ◽  
Pour Point ◽  
Crude Oils ◽  
Waxy Crude ◽  
Pour Point Depressants ◽  
Waxy Crude Oils
Sign in / Sign up

Export Citation Format

Share Document