流变仪响应特性对含蜡原油屈服应力测试结果的影响  

The effects of rheometer response characteristics on yield stress test results of waxy crude oil

作　　者：刘刚[1] 付伟娜[1] 滕厚兴[1] 张国忠[1] 陈雷[1] LIU Gang FU Weina TENG Houxing ZHANG Guozhong CHEN Lei(China University of Petroleum （Huadong）/Shandong Key Laboratory of Oil ＆ gas Storage and Transportation Safet)

机构地区：[1]中国石油大学(华东)/山东省油气储运安全省级重点实验室

出　　处：《油气储运》2017年第4期403-408,共6页Oil & Gas Storage and Transportation

基　　金：国家自然科学基金资助项目"胶凝原油管道启动问题中关键非定常参量研究";51574274;山东省自然科学基金资助项目"含蜡原油非线性黏弹特性研究";2014BSE28055

摘　　要：含蜡原油的屈服特性对管道停输再启动起主导性作用。目前,含蜡原油屈服应力大多利用实测的流变曲线,依据某判定条件确定。利用2台同为控制应力型但不同型号的流变仪开展实验,发现在测试的初始阶段,相同剪切加载条件下不同流变仪的实际响应特性(剪切率)不同,流变曲线差别较大;分析含蜡原油在2台流变仪下的屈服响应特性,发现其屈服应力、屈服应变差别较大,即含蜡原油屈服特性与流变仪加载后的实际响应特性密切相关。因此,含蜡原油屈服应力的确定需要考虑流变仪在测试过程中的实际加载条件。基于固体力学中材料强度极限的概念,将含蜡原油黏弹-触变模型中弹性应力的最大值定义为屈服应力。新提出的确定屈服应力的方法能够考虑流变仪在测试过程中的实际加载过程,物理意义也更加明确。Yielding characteristics of waxy crude oil play a dominating role in the shutdown and restart of pipelines. At present, yield stress of waxy crude oil is mainly determined by the measured rheological curves according to a certain criteria. In this paper, theological experiments were conducted on two stress-control rheometers of different types. It is shown that in the initial stages of testing, different rheometers have different actual response characteristics （shear rate） under the same shear loading condition, and the rheological curves vary greatly. Then, yielding response characteristics of waxy crude oil in two rheometers were analyzed. It is revealed that the yield stress and yield strain vary greatly. That is to say the yield characteristics of waxy crude oil are strongly associated with the actual response characteristics of rhcometer. To determine the yield stress of waxy crude oil, therefore, it is necessary to take into consideration the actual loading condition of rheometers in the process of testing. Based on the concept of ultimate material strength in solid mechanics, the maximum value of elastic stress in the viscoelastic-thixotropic model for waxy crude oil is defined as the yield stress. This newly proposed yield stress determination method takes into consideration the actual loading process of rheometers in the process of testing, so it is more definite in physical significance.

关 键 词：含蜡原油 屈服特性 屈服应力 流变仪 

分 类 号：TE832[石油与天然气工程—油气储运工程]