非均质稠油油藏聚合物驱吸液剖面变化规律研究

通过建立基于Buckley-Leverett方程的非均质油藏聚合物驱吸液剖面数学模型,研究了海上多层稠油油藏聚合物驱剖面变化规律。结果发现:稠油聚合物驱的吸液剖面有别于稀油,返转形态呈现倒"V"形,更易造成聚合物在高渗层低效循环,不利于聚合物驱开发;随着级差升高或聚合物浓度降低,返转高峰值与返转幅度降低,返转时机推迟,低渗层吸液量降低,聚合物改善纵向波及能力降低;随着注聚时机提前,返转幅度先小幅上升后明显下降,返转时机先提前后推迟,合理的注入时机有助于聚合物在各层的均衡推进。该研究成果对海上稠油油田聚合物驱持续高效开发具有重要的指导意义。

Polymer Flood Injection Conformance Behavior of Heterogeneous Heavy-Oil Reservoirs

An analytical mathematical model to predicate injection conformance behavior is constructed in this study for heterogeneous reservoirs based on the Buckley-Leverett function, thereby allowing to conduct research on heavy-oil polymer flood injection conformance behavior. Heavy-oil reservoir usually displays V type injection profile in comparison with light-oil reservoir, which indicates that less polymer is injected into the oil-rich low-permeability zone and it compromises EOR results. The conformance reversion scope significantly decreases with increasing permeability contrast, which weaken conformance improving capacity of polymer. The reversion scope first increases slightly and then decreases with earlier polymer flood, and the corresponding reversion timing first becomes earlier and then later, so proper polymer injection timing helps to create balance propagation in each layers. As porosity of low-permeability zone decreases, the conformance reversion timing delays and its injection amount increases, and the profile reversion phenomena can even disappear when porosity ratio of layers reaches to permeability contrast. In addition, the conformance reversion scope and polymer amount injected to low-permeability zone increases with increasing polymer concentration.