稠油冷采降黏剂分散机理与驱替实验评价

高效分散降黏剂是稠油冷采的关键,不仅具有静态洗油能力,而且能够扩散进入稠油胶质与沥青质之间,具有打散稠油结构的作用.在微观降黏机理研究的基础上,开展了L-A型稠油冷采吞吐降黏剂静态洗油、微观驱油、单砂层驱油和双层合采与分采驱油实验.L-A型降黏剂在稠油冷采中具有很好的使用效果,其主要机理为降黏剂分子间能形成很强的氢键,...

Dispersion Mechanism of Viscosity Reducer and Evaluation of Displacement Experiment for Cold Production of Heavy Oil

Efficiently dispersed viscosity reducer is the key to cold production of heavy oil. Viscosity reducer not only has a static oil washing ability, but also can diffuse into the spaces between colloid and asphaltenes in heavy oil, and break the structure of heavy oil. Based on the research of microscopic viscosity reduction mechanism, experiments on static oil washing, microscopic oil displacement, single sand-layer displacement, double-layer commingling production and separate oil displacement were carried out with L-A viscosity reducer which is suitable for cold huff and puff production of heavy oil. L-A viscosity reducer has a good effect on cold production of heavy oil. The main mechanism is that the viscosity reducer can form strong hydrogen bonds among its molecules. After intercalating into the molecules of heavy oil, the viscosity reducer filtrates and diffuses into the space between the lamellate colloid molecules and the lamellate asphaltenes molecules, reducing the hydrogen bonding force among the heavy oil molecules. The static oil washing efficiency of the L-A viscosity reducer at a mass fraction of 3% can reach 11.3%, and on microscopic displacement level, the L-A viscosity reducer can peel the heavy oil from particle surface. Single-layer displacement experiments show that the optimum viscosity-reducing mass fraction is 2%-3%, and the oil displacement efficiency reaches 48% at a lower flooding rate (1 mL/min). Double-layer experiments show that if the permeability ratio is not greater than 2, the maximum oil displacement efficiency at a low flooding rate can reach 40%, and the overall oil displacement efficiency decreases with the increase of the flooding rate and the increase of the permeability ratio between layers.