疏松砂岩出砂临界流量试验研究

Experimental study on sand production critical flowrate for unconsolidated sandstone

疏松砂岩地层出砂的危害极大,出砂临界流量的准确确定尤为重要。利用自行研制的出砂模拟试验装置,对青海油田N21储层进行了不同流体和覆压下的小岩心出砂模拟试验。结果表明:由不同压差的流量和渗透率变化、开始出砂的时间和出砂量的多少确定了不同小层的出砂临界流量;不同流体(非极性油和地层水)的出砂临界流量有很大差别,水驱临界流量明显大于油驱临界流量,储层的应力状态对出砂临界流速有很大的影响,试验结果指导了现场生产。

Because there is enormous hazard for the sand production in unconsolidated sandstone reservoir,accurate determination of critical flowrate is particularly important.Sand production simulation experiment of small cores with different fluid types and confining pressures is conducted for the N21 reservoir in Qinghai Oilfield by utilizing self-developed sand production simulation experimental device.The study results show that the sand production critical flowrate of different layers can be determined based on the variation of flowrate and permeability at different pressure differences,the time of initial sand production and the amount of produced sand;that the sand production critical flowrate of different fluid types（non-polar oil and formation water） is very different and the waterflooding critical flowrate is obviously greater than that of oil displacement;that the stress condition of reservoir has a great effect on sand production critical flowrate.The experiment result provides the direction for field production.