大庆油田MD膜驱提高采收率室内实验研究

Laboratory Experimental Studies on Enhancing Oil Recovery by Molecular Deposition Filming/Flooding at Daqing

在大庆主力砂岩油藏岩心上 ,考察了膜驱剂MD 1在不同开发阶段的驱油效果 (4 5℃ )。膜驱剂MD 1为含2 5 %单分子双季铵盐的工业品 ,用矿化度 5 2 10mg/L的油田采出水配制驱替液。注入 0 .5 7PV的 5 0 0mg/LMD 1溶液使未洗油、含束缚水的岩心表面由亲油变弱亲油 ,由弱亲油变中性。在洗油后饱和水 ,再用油驱替至束缚水状态的若干组岩心上 ,膜剂驱的采收率如下 :直接用 5 0 0mg/L溶液间歇驱油 ,采收率 6 0 .8%和 6 4 .1%;水驱后提高采收率 2 .2 3%(5 0 0mg/L× 0 .5PV) ,3.0 9%(10 0 0× 0 .5 ) ,9.10 %(5 0 0× 2 .0 ) ,8.2 0 (5 0 0× 10 .0 ) ,最终采收率略低于直接膜剂驱 ;水驱、聚合物驱 (提高采收率 6 .4 8%～ 8.6 1%)之后提高采收率 1.96 %(5 0 0× 0 .5 ) ,2 .4 4 %(10 0 0×0 .5 ) ,6 .4 8%(5 0 0× 5 .0 ) ,6 .4 6 %(5 0 0× 10 .0 ) ;水驱、三元复合驱 (提高采收率 14 .89%～ 15 .89%)之后提高采收率1.4 5 %(5 0 0× 0 .5 ) ,0 .6 5 %(10 0 0× 0 .5 ) ,5 .98%(5 0 0× 5 .0 ) ,5 .13%(5 0 0× 10 .0 )。在大庆油田 ,聚合物驱和三元复合驱之后采用膜驱技术可进一步提高采收率。表 4参

The oil displacing efficiency of molecular deposition filming/flooding (MDFF) agent MD 1, a commercial organic diammonium salt in 25% aqueous solution, is studied on the cores of Daqing main sandstone reservoirs at 45℃. The MD 1 flooding solution used is prepared in produced water of TSD =5 210 mg/L. Injecting 0.57 PV of 500 mg/L MD 1 solution into oily cores with irreducible water changes the core surfaces from oil wet to weak oil wet or from weak oil wet to neutrally wet. For several groups of reservoir cores deoiled, water saturated and flooded with oil to irreducible water state, MDFF gives rise to enhancement in oil recovery as follows: 60.8% and 64.1% in the case of injecting 500 mg/L solution discontinuously; 2.23% (500 mg/L×0.5 PV), 3.09%(1 000×0.5), 9.10% (500×2.0), and 8.25% (500×10.0) after water flood to 98% water cut with ultimate oil recovery slightly lower than that in the case of direct MDFF; 1.96% (500×0.5), 2.44% (1 000×0.5), 6.48% (500×5.0), and 6.46% (500×10.0) after water flood followed by polymer flood with enhancement in oil recovery of 6.48-8.61%; 1.45% (500×0.5), 0.65% (1 000×0.5), 5.98% (500×5.0), and 5.13% (500×10.0) after water flood followed by ASP combinational flood with enhancement in oil recovery of 14.89-15.89%. It is ascertained that the oil recovery might be further enhanced by using MDFF after polymer or ASP combinational flood at Daqing oil fields.