聚合物MO-4000与油藏渗透率的配伍性研究

A Study on Conformity of HPAM Polymer MO-4000 to Reservoir Permeability in EOR

研究了超高相对分子质量聚合物（HPAM）MO-4000与胜利高温高盐油藏的配伍性。用动态激光光散射法，在30℃、矿化度19334mg／L的胜利Ⅱ型盐水中，测得该聚合物水化分子线团的水动力学半径Rh主要分布在20～100nm范围，其平均值为39．1nm。用不同渗透率的12支石英砂胶结岩心，在80℃测定了水驱之后注入0．3PV的1500mg／LMO-4000盐水溶液得到的提高采收率值，当岩心渗透率由0．092μm^2逐步增至1．302μm^2时，聚驱提高采收率由12．61％增至16．63％，渗透率继续增至5．266时时，聚驱提高采收率则减至9，97％，MO-4000提高采收率的最适渗透率为0.2～2.0μm^2时。按经验公式由K、φ计算的实验岩心孔喉半径均值在1．78-10．78μm。根据颗粒堵塞多孔介质孔喉的架桥学说，颗粒半径小于孔喉半径的0．46倍时不造成堵塞，因此注入MO-40000盐水溶液不会堵塞目标油藏，根据岩心驱油实验结果，孔喉半径均值在2～6．5μm的油藏，与MO-4000的匹配性最好。图6表1参20。

The conformity of a commercial ultrahigh molar mass HPAM, Mitsubishi＇s MO-4000, to higher temperature and higher salinity oil reservoirs in Shengli is investigated experimentally. The hydrodynamic radius of hydrated molecular coils of MO-4000 at 30℃ in standard Shengli brine Ⅱ is determined by using dynamic laser light scattering and is distributed mainly in range 20-100 nm with an average value 39.1 nm. On 12 cemented quartz sand cores of varying permeability, having been water flooded, the enhancement in oil recovery by 0.3 PV of 1500 mg/L solution of MO-4000 in Shengli brine Ⅱ at 80℃ increases from 12.61% to 16.63% with increasing core permeability from 0. 092 μm^2 to 1. 302 μm^2 and then decreases down to 9.97 % with increasing core permeability further to 5. 266 μm^2 and the optimal core permeability for MO-4000 to enhance oil recovery is in range 0.2-2.0/μm^2. The pore throat radius mean of these cores calculated from the values of core permeability and porosity by using an empirical equation is in range 1.78-10.78 μm. According to a bridging concept for solid partifcles to blockage a pore theoat in a porous medium, the particles having a radius less than 0.46 times of a pore throat radius do not blockage the pore and hence MO-4000 in brine solution does not create blockages in aimed reservoirs and conforms best to the reservoirs with pore throat radius mean in range 2--6.5 μm, as shown above in core flooding tests.