断块油藏层系组合与液流转向措施对开发效果的影响

Development Effect Study on Layer Combination and Fluid Diversion Measure of Fault Block Reservoir

利用现代油藏工程理论、仪器检测和物理模拟方法,研究了合层模型渗透率级差、小层数和液流转向措施对开发效果的影响。转向剂最佳配方为:1.2 g/L部分水解聚丙烯酰胺、聚铬质量比180∶1、6 g/L氯化钠、污水;驱油剂为弱碱三元复合体系,由1.2 g/L部分水解聚丙烯酰胺、2 g/L重烷基苯磺酸盐、8 g/L Na2CO3、污水组成。结果表明,合层模型渗透率级差和小层数对水驱开发效果的影响较大。当渗透率级差由3倍增至30倍时,模型水驱采收率从40.4%降至35.4%;采取液流转向措施后,采收率增幅从5.3%增至8.5%。当模型小层数为2、3、4、5时,模型水驱采收率分别为37.5%、32.1%、33.2%和36.0%;采取液流转向措施后,采收率增幅分别为5.8%、7.2%、5.5%和4.7%。渗透率级差愈大,低渗透层分流率愈小。在渗透率级差和转向剂注入量相同时,随转向剂的不断注入,高渗透层分流率逐渐下降,中、低渗透层分流率逐渐增加。

The effect of permeability grading, stratum number, and fluid diversion measure on the development effect was carried out by modern reservoir engineering theory, instrument detection and physical analogue. The optimum formula of diversion agent was established： 1.2 g/L partially hydrolyzed polyacrylamide （HPAM）, 180：1 mass ratio of HPAM and chromium, 6 g/L sodium chloride and prepared sewage. Displacing agent was weak base ASP system which was composed of 1.2 g/L HPAM, 2 g/L heavy alkybenzene sulfonate （HABS）, 8 g/L NthCO3 and prepared sewage. The results showed that the permeability grading and stratum number of model influenced the development effect. When the permeability grading increased from 3 to 30, the recovery efficiency of water flooding decreased from 40.4% to 35.4%. The increment of recovery efficiency increased from 5.3% to 8.5% after fluid diversion measure. When the stratum number was 2, 3, 4 and 5, the recovery efficiency of water flooding was of 37.5% ,32.1% ,33.2% and 36. 0%, respectively. The increment of recovery efficiency was of 5.8% ,7.2% ,5.5% and 4.7% after fluid diversion measure. The permeability grading became larger, the diversion rate of low permeability layer was lower. The diversion rate of high permeability layer decreased, while that of middle and low permeability layers increased, with the same permeability grading and diversion agent injection.