用储能模量表征含蜡原油的屈服值

含蜡原油的屈服性能直接影响其管输安全，当温度降低时，含蜡原油析出的蜡晶与其中的胶质、沥青质相互作用形成具有一定强度的三维空间网络结构，在外剪切力作用下，该结构屈服裂降，存在一个屈服值，即屈服应力。通过应变扫描实验法对长庆、大庆、环江、冀东4种含蜡原油进行流变性测试，结果表明：含蜡原油在线性黏弹区内储能模量基本不变，应力与应变呈线性递增关系，其线性黏弹区随着温度的升高而增大；含蜡原油的储能模量与屈服值在双对数坐标图上呈现线性递增关系，可以用结构屈服系数表示含蜡原油屈服时结构的强弱，该系数等于储能模量和屈服值的对数比值。与其他方法相比，该方法获得的屈服值结果更加稳定，易于形成相关标准。（图2，表2，参9）

Characterization of yield value of waxy crude oil with storage modulus

The yield behavior of waxy crude oil directly affects the safety of pipeline transportation. When the temperature decreases, wax crystals precipitated from waxy crude oil interact with the resin and asphaltene present in the oil, forming a three-dimensional network structure with a certain strength. Under the external shearing force, this structure is yielded and fractured, at a yield value, i.e., yield stress. Rheology tests of Changqing, Daqing, Huanjiang River and Jidong waxy crude oil were carried out through strain sweep experiments. Results show that the storage modulus of the crude oil have remained basically unchanged in linear viscoelasticity region which increases with the increase of temperature, and stress increases linearly with strain. Storage modulus and yield value of waxy crude oil present a linear increase relationship in the log- log graph. The structural yield coefficient, which is equal to the log ratio of storage modulus to yield value, is introduced to represent the strength of the structure when waxy crude oil yields. Compared with other methods, the yield value obtained by this method is more stable, making it easier to form relevant standards. （2 Figures, 2 Tables, 9 References）