含聚合物疏松砂岩岩心出砂形态微观模拟实验

Microscopic simulation experiments on sand production morphology of polymer-bearing unconsolidated sandstone cores

周博,董长银,王力智,刘晨枫,赵益忠,魏彩霞,宋洋

中国石油大学（华东）石油工程学院，山东 青岛 266580 中国石化胜利油田分公司石油工程技术研究院，山东 东营 257000

聚合物驱的疏松砂岩油藏中，生产井近井地带聚合物衍生物聚集会造成储层堵塞，同时也会对储层出砂产生影响。为探究聚合物驱油藏注聚井和油井聚合物赋存条件下的出砂机理和出砂形态，利用可视化微观出砂模拟实验装置，使用粒径中值为0.3 mm的地层砂，固化胶结得到聚合物赋存条件下的弱胶结岩心薄片；分别使用清水和新鲜聚合物进行出砂驱替实验，并借助光学显微镜观察实验过程中岩心薄片颗粒微观运移过程和出砂形态，分析新鲜聚合物及聚合物衍生物对弱胶结储层出砂形态的影响。结果表明：新鲜聚合物因黏性流体的拖曳作用增大了出砂风险，亏空区域面积是无聚合物条件下的7~10倍；聚合物衍生物聚团会阻挡出砂的类蚯蚓洞延伸，边界绕流加剧聚合物堵塞区边缘出砂，在近井高流速区尤为严重，亏空区域面积是无聚合物条件下的2~5倍。利用岩心微观模拟方法，可实现对不同聚合物赋存状态下出砂形态的刻画，可开展储层出砂形态微观模拟实验的研究，对聚合物驱防控砂和聚合物驱储层开采优化具有一定的指导意义。

In unconsolidated sandstone reservoir with polymer flooding, the accumulation of polymer derivatives in the near-well zone of the production well will cause blockage and also affect the sand production of the reservoir. In order to explore the sand production mechanism and morphology of polymer injection wells and oil wells under polymer occurrence states, the formation sand with a median particle size of 0.3 mm was solidified and cemented to obtain weakly cemented core slices with polymer presence by using the visual micro sand production simulation experiment device. Clean water and fresh polymer were used for sand production displacement experiment. We use optical microscope to observe the microscopic particle migration process and sand morphology during the experiment, and analyze the influence of fresh polymer and polymer derivatives on the sand production morphology of weakly cemented reservoirs. The results show that the fresh polymer increases the risk of sand production due to the drag effect of the viscous fluid, and the deficit area is 7 to 10 times that of the polymer-free condition. The polymer derivatives compound micelles will block the extension of the sandy earthworm hole and boundary flow mechanism increases sand production at the edge of polymer blockage zone which is particularly serious in the high-velocity area near the well, and the area of the deficit area is 2 to 5 times that of the polymer-free condition. The core microscopic simulation method can realize the characterization of the sand production morphology under different polymer occurrence state, and carry out the microscopic simulation experiment of the reservoir sand production morphology. It has certain guiding significance for optimizing sand control technology and production in polymer flooding reservoir.

10.6056/dkyqt202106023