新疆油田砾岩油藏聚合物驱窜流特征及调剖对策

聚合物驱过程中的聚合物窜流是影响聚合物驱效果的重要因素。针对七东1区克下组砾岩油藏特殊的复模态孔隙结构，通过室内并联岩芯物理模拟实验研究了聚合物驱窜流特征及调剖对策。研究表明，砾岩油藏渗透率变异系数低于0.3时，聚合物驱不发生窜流；渗透率变异系数高于0.5时，聚合物改善剖面作用有限，发生窜流，且窜流导致聚合物驱见效后高渗岩芯含水率迅速回升；随着渗透率变异系数增大，聚合物在高渗层突破时间缩短，聚窜发生越早和越严重，聚窜后高渗层吸液百分数从52%增大到75%；聚窜后及时调剖，能有效控制聚窜和发挥聚合物驱作用，采收率提高28.75%；聚合物驱全过程调剖是治理聚窜的理想对策。

Channeling Characteristics and Profile Modification Measures for Polymer Flooding in Conglomerate Reservoirs in Xinjiang Oilfield

Polymer flooding channeling is an important factor affecting polymer flooding. Targeting the complex mode pore structure, which is special to the conglomerate reservoirs in Qidong-1 Area, crossflow characteristics and profile modification measures of polymer flooding were studied through physical simulation experiments conducted indoors in parallel with those at the rock cores. The study shows that, when the permeability variation coefficient of the conglomerate reservoirs is less than 0.3, no crossflow occurs in polymer flooding; when it is larger than 0.5, the effect of profile improvement by the polymer is limited, and channeling occur, which lead to a rapid rebound in water content of highly permeable cores after polymer flooding takes effect. As the permeability variation coefficient increases, the time taken for the polymer to break through the highly permeable layer is shortened, channeling occur earlier and more severely, and subsequently, the percentage of liquid absorption in the highly permeable layer is increased from 52% to 75%. With timely profile modification after channeling, channeling can be effectively controlled while polymer flooding takes effect, increasing the recovery rate by 28.75%.