【摘要】 同时考虑应力敏感与启动压力梯度的影响,推导出拟稳态流动阶段致密砂岩油井产能公式;并在研究井底脱气基础上,对产能方程进行了修正。实例计算结果表明:在相同的生产压差下,生产井产能向压力轴弯曲,产能低于常规Vogel方程;且应力敏感系数越大,产能曲线弯曲度越大。当井底存在脱气现象时,油井存在一个极限生产压差,并当极限生产压差低于实际生产压差时,油井产量随着生产压差增大反而下降;应力敏感系数越大,产能曲线弯曲越早且弯曲度越大,极限生产压差减小。受到启动压力梯度影响,生产井极限生产压差变大,而受到应力敏感效应影响,极限生产压差减小。在实际生产过程中需要合理优化生产压差。地层压力下降后,生产井受到应力敏感效应影响减弱,受到启动压力梯度影响增强。更多还原

【Abstract】 A new productivity equation was presented in pseudo-steady state in tight reservoir,considering the effect of stress sensitivity and threshold pressure gradient. And the equation has been modified with taking bottom hole degassing into consideration. The computation result of an example showed that: the IPR curve of producer bended to pressure axis and the productivity was lower than Vogel equation. The bigger the stress sensitive coefficient was,the greater the bend degree of IPR curve became. When it took bottom hole degassing into account,there was a critical producing pressure drop in the well,when the actual producing pressure drop exceed the critical producing pressure drop,the productivity would decrease. The larger stress sensitive coefficient was,the earlier and heavier IPR curve bended,and the lower the critical producing pressure drop was. Due to threshold pressure gradient,the critical producing pressure drop would increase,however it would decrease for stress sensitivity. So it was necessary to optimize producing pressure drop during production process. With the decrease of reservoir pressure,the effect of stress sensitivity would be decreased and the effect of threshold pressure gradient would be increased.更多还原