基于潜力预测模型的聚合物驱参数敏感性分析

Sensibility Analysis of Polymer Flood Parameters by Using a Novel Potential Predictive Mathematical Model

采用流线方法建立了一种新的预测聚合物驱提高采收率潜力的数学模型.给出了该模型的假设条件和基本数学式,讨论了纳入该模型的聚合物驱物理物化参数.利用该模型预测了一个拟三维油藏五点式井网井组模型(5层10 m厚油层,平均渗透率2 μm2,渗透率变异系数0.7,孔隙度20%,原始含水饱和度30%,原始地层压力10MPa,温度50℃,地层原油粘度60mPa·s),以80m3/d流量依次注水0.4PV、注1700 mg/L聚合物溶液0.3PV、后续注水,所得采出程度～含水率曲线与国外数值模拟软件VIP-POLYMER的计算结果一致.利用该模型考察并分析了地层原油粘度(10～90 mPa·s),地层温度(30～80℃),地层水矿化度(5×103～3×104mg/L),渗透率变异系数(0.1～0.9),聚合物溶液粘度(5、10、15 mPa·s),渗透率下降系数(1.5、2.0、2.5),不可及孔隙体积分数(0.5～0.0),吸附性质(无吸附、不可逆吸附、可逆吸附)、聚合物浓度(500～2500mg/L),聚合物段塞尺寸(0.1～0.6PV),聚驱时含水率(60%～95%)等油藏参数、聚合物性质参数、注入工艺参数对聚合物驱效果(提高采收率或含水率曲线)的影响.图13表3参3.

A novel mathematical model （MM） for predicting polymer flood potential is established by using a streamline method. The conditional assumptions and the mathematical expression of this model are presented and the physical and physicochemical parameters in polymer flood taken into consideration are discussed. Applying this MM to a physical model of five-spot well group in a quasi 3D reservoir of total thickness 10 m per 5 layers, permeability 2 μm^2 in average, permeability variance coefficient 0.7, porosity 20%, initial water satuation 30%, initial formation pressure 10 MPa, formation tamperature 50℃, viscosity of oil in-place 60 mPa·s, and TSD in formation water 10 g/ L in a simulation flood according to following injection procedure at flow rate 80 m^3/d： 0.4 PV of water under initial reservoir conditions -0.3 PV of 1700 mg/L polymer solution-water up to 98% water cut, the curve of oil recovery vz water cut obtained agrees fair good with that computerized by using digital simulation software VIP-POLYMER. The effects upon the oil displacement efficiency by polymer flood are investigated, analyzed and discussed for various parameters characterizing the aimed reservoir, the polymer performance, and the injection technology such as viscosity of oil in-place （ 10--90 mPa· s）, reservoir temperature （30--80℃）, TSD） in formation water （5--30 g/L）, permeability variance factor （0.1--0.9）, viscosity of polymer solution （ 5,10, and 15 mPa· s）, permeability reduction factor （1.5, 2.0, and 2.5）, inaccessible piore volume fraction （0.5--0.0）, adsorption nature （non-adsorption ,irreversible and reversible adsorption ） and concentration （500--2500 mg/L） of polymer, polymer slug size （0.1-0.6 PV）, and water cut at the beginning of polymer flood （60---95%）.