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The Effect of Structure of Viscosity Reducer to Viscosity Reducing Effect for Heavy Oils

ZHU Jing,LI Chuan-xian,XIN Pei-gang

Abstract （685）

PDF （253KB）（532）

The high viscosity of heavy oil and studies the effect of construct and combination of oil-soluble viscosity reducer on viscosity reducing effect were discussed. The results show that unary-polymer has viscosity action and poor viscosity reducing effect, binary-polymer has definite raise and viscosity reducing rate exceeds 30% in 20 ℃, terpolymer containing twain or more polar functional group researches has preferable effect and viscosity reducing rate is concordant with 70% in 20 ℃, and advisable combination in difference viscosity reducer can display synergism and raise the viscosity reducing effect obviously.

2011, 24 (3): 39-42. DOI: 10.3696/j.issn.1006-396X.2011.03.010

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Analysis of Viscosity-Temperature Characteristics and Rheology Behavior for Heavy Oil

ZHU Jing,LI Chuan-xian,XIN Pei-gang

Abstract （958）

PDF （229KB）（776）

Viscosity-temperature characteristics and rheology behavior for heavy oil were measured and researched by using RS75 rotary viscosimeter. The results show that viscosity-temperature characteristics are according with Arrhenius equation in temperature interval (80~20 ℃), viscosity is more sensitive to temperature changes in lower temperature, the activation energy rises 40% in lower temperature interval （36.5~20.3 ℃）more than in higher temperature interval（80.0~55.9 ℃）, and heavy oil is Newtonian fluid above anomalistic point（35 ℃）, non-newtonian fluid and without thixotropic property below anomalistic point.

2011, 24 (2): 66-68. DOI: 10.3696/j.issn.1006-396X.2011.02.017

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Effects of Emulsification Conditions on the Rheological Properties of Heavy Oil－in－Water Emulsions

YANG Fei,LI Chuan-xian, LIN Ming-zhen,GUO Gang

Abstract （1302）

PDF （290KB）（1163）

The effects of emulsification conditions (including oil/water volume ratio, emulsifier concentration, emulsifying temperature, emulsifying time and stirrer rotation speed) on the rheological properties of heavy oil-in-water emulsions were studied by using polarized-light microscope and control-stress rheometer. The results show that the droplet size and viscosity of heavy oil-in-water emulsions are increased by increasing oil/water volume ratio (1∶9~7∶3); however, when the oil/water volume ratio is high (8∶2), an emulsion inversion (from O/W to W/O) occurs, leading to a sharp increase of emulsion viscosity. With the increase of emulsifier concentration (0.5%~5%), the emulsion droplet size decreases while the emulsion viscosity decreases first, and then increases. When emulsifier concentrations are not reach to 4%, the emulsions are Newtonian fluids; the emulsion changes into non-Newtonian fluid when the emulsifier concentration reaches 5%. The emulsion droplet size and viscosity are decreased by increasing emulsifying temperature (40~70 ℃). When emulsifying temperatures is above 70 ℃, an emulsion inversion occurs due to the invalidation of emulsifier, causing a sharp increase of emulsion viscosity. With the increase of emulsifying time and stirrer rotation speed, the emulsion droplet size decreases while the emulsion viscosity increases. The non-Newtonian characteristics of the emulsions become obvious with increasing emulsifying time and stirrer rotation speed.

2009, 22 (3): 51-54. DOI: 10.3696/j.issn.1006-396X.2009.03.013

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Depressive Effect of Polyacrylate （PA） Pour Point Depressant on Waxy Crude Oils

YANG Fei, LI Chuan-xian, LIN Ming-zhen, LI Zhi-yan, YU Tao

Abstract （1830）

PDF （464KB）（706）

Using differential scanning calorimeter （DSC ）， the crystallization abilities of polyacrylate （PA） pour point depressant and waxy crude oils doped/undoped with PA were studied；then the morphology of wax crystals in the waxy crude
oils doped/undoped with PA was investigated through a polarized light microscope and the depressive effect of PA on Changqing and Qinghai waxy crude oils was evaluated by the pour point tests and rheological experiments．The results show that the crystallization ability of PA improved greatly by increasing the alkyl side chain length of PA but kept unchanged with the increase of average molecular weight of PA．The addition of PA can inhibit the wax precipitation and decrease the wax appearance temperature of waxy crude oils．The size of wax crystals become larger and the structure of them become compact after PA addition，leading to the great improvement of the low temperature rheology of waxy crude oils．The depressive effect of PA on waxy crude oils are related to the crude oil composition and the molecular structure of PA．With the increasing of wax content and the fraction of wax with large carbon number， the depressive effect greatly decreased． The average molecular
weight of PA affected its depressive effect by controlling the solubility of PA in waxy crude oils：the solubility of PA in crude oils decreased with increasing the average molecular weight of PA， thus reducing the interactions between waxes and PA molecules and inhibiting the depressive effect of PA．The better matching the alkyl side chain of PA with the carbon number ofwax in crude oils，the better depressive effect of PA．

2009, 22 (2): 20-25.

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Effect of Buried Depth on Thermodynamic Properties of Hot Oil Pipeline in Steady Operation

LIN Ming-zhen， LI Chuan-xian， YANG Fei

Abstract （384）

PDF （1833KB）（318）

Based on impact of buried depth on thermodynamic properties of hot oil pipeline, the method that pipe sections with different buried depths were treated with different radius of heat influence. Heat differential equation of hot oil pipeline in steady operation was solved by means of finite element method, and calculation software was programmed to calculate the axial and transverse temperature field of pipeline. It was found that the result calculated by the software was more accurate. The effect of buried depth on the thermodynamic properties of pipeline in different seasons was also discussed in detail. The results indicate that if the calculated depth is larger than the actual value in winter, the calculated result of temperature field is larger than actual value, which is adverse for safety of pipeline operation. Otherwise, a smaller calculated buried depth would generate a smaller calculated result of temperature field, which would lead to costly pipeline operation. In summer, the situation is the opposite.

2008, 21 (3): 63-67.