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在常温或深海低温条件下,含蜡原油与水形成的W/O型乳状液易发生胶凝,容易对管道再启动安全性造成威胁。基于含蜡原油乳状液凝胶复杂的流变行为,分别探讨黏塑性和黏弹性两类含蜡原油触变模型对其乳状液凝胶的适用性。通过对比目前常用于含蜡原油的4种黏塑性触变模型,以及近期发展的黏弹性触变模型,筛选出能够准确描述乳状液凝胶加载后整个流变响应过程的模型。通过实验数据拟合发现,滕厚兴提出的黏弹性触变模型对包括屈服前蠕变和屈服后裂降的整个过程的描述最准确;在黏塑性触变模型中,滕厚兴提出的黏塑性模型对屈服点后裂降过程的描述结果偏差最小,而传统的Houska黏塑性模型对乳状液凝胶裂降过程的描述效果不佳,主要是由于该模型的速率方程与实际裂降过程不符。由于黏塑性触变模型无法描述屈服点之前的黏弹性响应,因此推荐采用滕厚兴的黏弹性触变模型进行管道再启动计算。
W / O emulsions formed from waxy crude oil and water tend to gel at room or deep sea temperatures, posing a threat to the safety of pipeline restart. Based on the complicated rheological behavior of waxy crude emulsion, the applicability of viscoelasticity and viscoelasticity two types of waxy crude thixotropic model to their emulsion gels were discussed respectively. By comparing the four kinds of visco-plastic thixotropic models commonly used in waxy crude oil and the recent development of the viscoelastic thixotropic model, a model capable of accurately describing the entire rheological response process after the emulsion gel is loaded is selected. Through the experimental data fitting, it is found that the viscoelastic thixotropy model proposed by Teng Houxing is the most accurate description of the whole process including pre-yield creep and post-yield rupture. In the viscoplastic thixotropy model, the visco-plastic model proposed by Teng Houxing However, the traditional Houska viscoplastic model is not effective in describing the destructive process of emulsion gel because the rate equation of the model does not match the actual destructive process. Since viscoelastic thixotropic model can not describe the viscoelastic response before yield point, it is recommended to use Teng Houxing viscoelastic thixotropic model for pipeline restart calculation.