稠油分散性降黏剂的降黏效果及其微观驱油机理*

Viscosity Reduction Effect Evaluation and Micro-flooding Mechanism of Dispersive Viscosity Reducer for Heavy Oil

李洪毅

LI Hongyi

为解决胜利油田稠油热采开发成本高的问题，考察了一种分散性降黏剂L-A对胜利油田稠油的降黏效果， 分析了稠油降黏前后的分子结构和黏附力变化，利用微观可视化驱油实验模型研究了微观驱油机理。研究结果 表明，在地层温度56 ℃下，分散性降黏剂L-A溶液最佳质量分数为2.0%，降黏剂溶液与稠油最佳体积比为1∶6， 降黏率达到94.58%。降黏剂与稠油混合后，降黏剂中的磷羟基P—OH基团与羧酸根—COOH等极性基团插层 进入稠油分子间，拆散胶质沥青质的复杂片状分子结构，破坏胶体分散体系与胶质沥青质空间网络结构，分子结 构变得松散，缔合作用减弱，黏附力降低，分子间内摩擦力下降，导致原油黏度降低。分散性降黏剂L-A分子微 观上能够将吼道盲端、并联喉道以及低渗通道小孔喉区域的剩余油分散携带并剥离，具有洗油和调驱能力。

In order to solve the problem of high development cost of heavy oil thermal recovery in Shengli oilfield，the viscosity reduction effect of a dispersive viscosity reducer L-A was investigated，the changes of molecular structure and adhesion force of heavy oil before and after viscosity reduction were analyzed. The micro-flooding mechanism was studied with microscopic visual oil displacement experimental model. The results showed that when the optimal concentration of dispersive viscosity reducer solution was 2% at formation temperature of 56 ℃，and the optimal volume ratio of viscosity reducer solution to heavy oil was 1∶6， the viscosity reduction rate reached up to 94.58%. When the viscosity reducer was mixed with heavy oil，the P—OH group and carboxylic acid —COOH in the viscosity reducer intercalated into the heavy oil molecules，as a result，the complex sheet molecular structure of gum and asphaltene was broken，and the space network structure of colloidal asphaltene was destroyed. The molecular structure became loose，the association effect was weakened，the adhesion force decreased，and the internal friction between molecules declined，which led to the viscosity of crude oil decreased obviously. On the microscopic level，the dispersive viscosity reducer L-A could disperse and separate the remaining oil from the blind end of the throat，parallel throat and small hole throat of the low permeability channel，demonstrating the ability of oil displacement efficiency and profile control.

10.19346/j.cnki.1000-4092.2021.04.023