大庆低渗透砂岩储层矿物组成对油层改造的影响

INFLUENCE TO OIL HORIZON REFORMATION BY MINERAL COMPOSITION OF DAQING LOW──PERMEABLE SANDSTONE RESERVOIR1)

针对大庆油田低渗透砂岩储层的特点 ,研究了陆相砂岩矿物的组成特征与海相砂岩的区别及对油层改造的影响 ,认为 :在酸化过程中 ,骨架颗粒组分溶解造成大量粘土微粒的释放和各种新生的化学沉淀 ,它们对孔隙喉道的堵塞是导致严重油层污染的最主要根源 ,也是导致目前低渗透砂岩储层酸化效果较差和油层减产的一个重要原因。寻找一种既能保持骨架颗粒稳定 ,又能溶解孔隙中的粘土矿物 ,改善低渗透砂岩的渗滤性能和油层产能的酸化技术 ,是大庆低渗透砂岩进行酸化改造的关键。

Countering the peculiarity of low-permeable sandstone reservoir of Daqing oil field, having studied the compositional feature of continental facies sandstone minerals different from that of marine facies sandstone, and its influence to oil-horizon reformation; it is deemed that in the process of acidization, the solution of skeletal grain component makes the release of large amount of clay particles and various new-generated chemical precipitates, their plugging pore-throats is the chiefest origin leading to oil horizon severely contaminated, and is also an important cause resulting in worse acidization effect and oil-horizon yield reduction of low-permeable sandstone reservoir currently. Finding out an acidization technique that can both keep the skeletal grain stable and solve clay minerals in pores, improving the permeable performance and oil-horizon productivity of low-permeable sandstone is the key of conducting acidization reformation for Daqing low-permeable sandstone.