摘要
为了优选出一种适合室内测定启动压力梯度的围压控制方法,应用先进的ASF300TM设备分别开展了恒定围压和恒定净围压2种控制模式下的实验。每种控制模式分别以恒定注入压力和恒定注入流量的方式向实验岩心注入实验流体,最终将实验测试结果进行回归拟合计算,得到4种不同的启动压力梯度值,并根据不同实验条件对实验结果进行详细分析,结合应力敏感实验和有效应力理论的结论,对上述4种结果进行综合评价。经分析可知:在恒定围压模式下测得2组启动压力,但数值都偏大;为降低实验误差,可将净围压控制在11 MPa以上,在恒定净围压模式下,测试结果准确。因此,在恒定注入压力方式下,以恒定净围压模式开展实验是室内测试致密岩心启动压力梯度比较理想的方法。
In order to optimize and obtain a method for control of confining pressure suitable for lab determination of starting pressure gradient,an experiment at two control modes – constant confining pressure and constant net confining pressure was made respectively by use of advanced ASF 300TM equipment. At each mode,experimental fluid was injected into the experimental core at constant injection rate under constant injection pressure,finally,the experimental results were regressed for fitting calculation to get 4 types of starting pressure gradient value,which were analyzed in detail under different experimental conditions and analyzed comprehensively in combination with stress sensitivity experiment and effective stress theory. It is known from analysis that,two sets of starting pressure value measured at constant confining pressure are equivalent,but greater; to reduce the experimental error,the net confining pressure can be controlled greater than 11 MPa,and the tested result is precise at constant net confining pressure mode. Therefore,at constant injection pressure,experiment at constant net confining pressure mode is a desirable method to perform a test of starting pressure gradient of tight core in lab.
出处
《特种油气藏》
CAS
CSCD
北大核心
2014年第2期107-110,156,共4页
Special Oil & Gas Reservoirs
基金
教育部专项"多孔介质中油水细观流动理论和动力学机制研究"(FRF-MP-B12006B)
关键词
启动压力
围压控制
净围压
应力敏感
有效应力
实验
starting pressure
control of confining pressure
net confining pressure
pressure sensitivity
effective stress
experiment
