摘要
采用长时间加载围压的方法,模拟了致密储层长时间承压的应力敏感效应。研究表明,围压加载时间越长,致密储层的应力敏感越严重。建立了基于时间尺度的致密储层应力敏感评价方法,将致密储层的应力敏感在时间尺度上划分为两个阶段,即瞬时应力敏感段和延时应力敏感段,致密储层常规应力敏感评价方法只考虑了瞬时应力敏感,而忽略了延时应力敏感。实验结果显示,两者的差值最高可达30%,说明在长时间的开发过程中,延时应力敏感不容忽视。在致密储层应力敏感评价时,有效应力加载时间应达到延时应力敏感段中的延时衰减敏感段,直到拟合出指数衰减方程为止,依据指数衰减方程和实际生产情况计算矿场生产时间尺度的延时应力敏感。新建立的评价方法能够更准确地模拟致密储层的实际应力敏感特征,对致密储层的合理开发具有重要指导意义。
Experiments about tight reservoirs are performed by confining pressure to simulate tight reservoirs under pressure for a long time during production process.The results show that the stress sensitivity is increasing with compression time extended.Evaluation method for stress sensitivity about tight reservoirs was established based on time scale.The stress sensitivity for tight reservoirs was divided into two feature segments from time scale,which were named instantaneous stress sensitivity and delayed stress sensitivity.The conventional evaluation method for stress sensitivity about tight reservoirs has only considered the instantaneous stress sensitivity,and the delayed stress sensitivity has been ignored.The difference of the two is up to 30%,which shows that the delayed stress sensitivity can not be neglected.When evaluated stress sensitivity for tight reservoir level,the load time of stress effective should continue until delayed attenuation stress sensitivity comes,and the exponential decay equation shouled be got.The exponential decay equation and the actual production conditions will leverage to caculate the dalayed stress senstitivity under in-site production time scale.The new method can more accurately simulate the stress sensitivity for tight reservoir,which has great guiding significance in rational development for tight reservoir.
出处
《非常规油气》
2016年第4期21-24,共4页
Unconventional Oil & Gas
关键词
致密储层
应力敏感
有效应力
渗透率
Tight reservoirs
stress sensitivity
effective stress
permeability
