不同熟化程度的聚合物在多孔介质中的渗流规律及驱油性能

Seepage and Oil Displacement Rules of Polymers with Different Curing Degrees in Porous Media

元福卿 宋 倩 季岩峰 李海涛

YUAN Fuqing SONG Qian JI Yanfeng LI Haitao

聚合物在注入地层过程中受到的物理、化学降解严重，黏度损失大。为了减少聚合物注入过程产生的黏度 损失，提出不完全熟化聚合物驱油技术。在70 ℃下，通过改变机械搅拌器的搅拌时间，制得具有不同黏度和熟 化程度为60%～100%的聚合物体系；基于宏观和微观模型对不同熟化程度聚合物在多孔介质中的渗流规律及 驱油性能进行研究。结果表明，相较于完全熟化聚合物，不完全熟化聚合物体系具有更好的黏弹性，可更好地动 用残余油、提高微观驱油效率；不完全熟化聚合物体系可以建立更高的阻力系数和残余阻力系数，经多孔介质剪 切后可以保留更高的有效驱替黏度；聚合物熟化程度过低不利于聚合物进入油藏深部，60%熟化程度聚合物体 系堵塞主要发生在靠近填砂管注入端0—1/5处，而80%和100%熟化程度聚合物体系堵塞主要发生在靠近填砂 管注入端1/5—2/5处；相对于水驱，60%、80%及100%熟化程度聚合物宏观驱油的采收率增幅分别为26.2百分 点、29.0百分点和23.3百分点，微观驱油的采收率增幅分别为37.3百分点、44.9百分点和36.0百分点。对于非均 质油藏，由于不完全熟化聚合物残留的未溶解胶团颗粒具有良好的封堵调驱性能，提高了低渗透层的吸液量，扩 大了波及体积，从而提高了低渗透层的采收率。研究结果可为不完全熟化聚合物驱油现场试验提供一定的理论 指导。

During the injection process into the formation，polymers undergo severe physical and chemical degradation，resulting in significant viscosity loss. In order to reduce the viscosity loss during the polymer injection process，the concept of partially cured polymer oil displacement technology is proposed. At 70 ℃，polymer systems with different viscosities and curing degrees ranging from 60% to 100% were prepared by varying the stirring time of mechanical stirrer. The study investigated the seepage characteristics and oil displacement performance of polymers with different curing degrees in porous media based on macroscopic and microscopic models. The results showed that compared to fully cured polymers，partially cured polymer systems exhibited better viscoelastic properties，enabled better mobilization of residual oil and improved microscopic oil displacement efficiency. Partially cured polymer systems could establish higher resistance coefficients and residual resistance coefficients，and then could retain higher effective displacement viscosities after shearing through porous media. The degree of polymer curing was too low to facilitate the entry of polymers into the deep part of reservoir. In polymer system with curing degree of 60%，the blockage mainly occurred near the injection end of sand-filled tube at 0—1/5 distance，while in polymer systems with curing degrees of 80% and 100%，the blockage mainly occurred near the injection end of sand-filled tube at 1/5—2/5 distance. Compared to water flooding，the incremental oil recovery rates of macroscopic oil displacement for polymer systems with curing degrees of 60%，80% and 100% were 26.2 percentage points，29.0 percentage points，and 23.3 percentage points，respectively. Meanwhile，the incremental oil recovery rates of microscopic oil displacement were 37.3 percentage points，44.9 percentage points，and 36.0 percentage points，respectively. For heterogeneous reservoirs，the residual undissolved polymer particles in partially cured polymers exhibited good plugging and conformance control properties. As a result，the liquid absorption in low-permeability layers was increased，the affected volume was expanded，and thus the recovery rate of low-permeability layers was enhanced. The research results could provide theoretical guidance for field tests of partially cured polymer oil displacement.

10.19346/j.cnki.1000-4092.2024.02.014