高含水期油藏储集层物性变化特征模拟研究

在华北油区的5个主力高含水期砂岩油田不同沉积微相带上选取了具有可对比性的292块岩样,采用室内模拟实验技术、密闭取心井分析技术和示踪剂监测技术,对储集层物理特征的变化进行了研究。结果表明,曲流河道和水下分流河道储集层物性相对较好,长期水驱后变化幅度较大,其渗透率和孔喉半径分别升高了38%和17%,排驱压力和粘土矿物含量分别约降低了23%和24%.河口坝和近岸滩坝储集层物性较差,长期水驱后其变化幅度相对较小,渗透率和孔喉半径分别升高了17%和12%,排驱压力和粘土矿物含量分别约降低了11%和17%.各种储集层敏感性减弱,油水相对渗透率曲线发生了一定程度的变化,油层润湿性主要从弱亲水变为强亲水。该研究成果在制定高含水期油田开发调整方案、选择注采调整措施及设计三次采油方案中得到较好的应用。

Simulation on variation of physical properties in high water-cut reservoir

Two hundreds and ninety two blocks of rock samples were selected from different micro*$-sedimentary facies in five main sandstone reservoirs during high water-cut production period in Huabei Oilfield. The changes of physical properties of reservoir in Huabei Oilfield were quantitatively studied,by using techniques of simulation tests in laboratory,sealed coring well analyses and tracer monitors. After long-term water flooding,the reservoir physical properties of meandering channels and the subaqueous channels were better. The permeability and the radius of porous throat were raised by 38 percent and 17 percent respectively. The drainage pressure and content of clay mineral were reduced by 23 percent and 24 percent respectively. The reservoir physical properties of the mouth bar and inshore beach bar have less changes after a long-term water flooding. The oil-water relative permeability curve changed,and the reservoir wettability changed from weak hydrophile to strong hydrophile.The permeability and radius of porous throat increased by 17 percent and 12 percent respectively,and the drainage pressure and content of clay mineral reduced by 11 percent and 17 percent respectively. The study result has been successfully applied to make the development and adjustment projects,select routine measures and design project for enhancing oil recovery of an oilfield during high water cut production stage.