岩性突变体对水力裂缝延伸影响的实验研究  

Experimental study on the effects of salutatory barrier on hydraulic fracture propagation of cement blocks

作　　者：金衍[1] 陈勉[1] 周健[1] 耿宇迪[1] 

机构地区：[1]中国石油大学石油工程教育部重点实验室,北京102249

出　　处：《石油学报》2008年第2期300-303,共4页Acta Petrolei Sinica

基　　金：国家自然科学基金项目(No.50304010和No.9051005)资助

摘　　要：产层水平方向常夹杂着岩性突变体,并且会阻碍水力裂缝在缝长方向的扩展或改变水力裂缝的扩展方向,从而影响水力压裂的效果。室内物理模拟实验研究发现,突变体法向应力对水力裂缝能否穿过突变体起着决定性作用,约4MPa的法向应力差可以促使水力裂缝穿透突变体,继续沿原来的方向延伸。产层与突变体之间的弹性模量差异、断裂韧性差异以及缝内净压力无因次量是影响裂缝走向的重要因素。水力裂缝穿过突变体需要比较大的能量积累,泵压会有显著波动。There are some salutatory barriers in the horizontal direction of pay zone, which maybe hinder the propagation of hydraulic fracture or change the propagation direction of hydraulic fracture,as a result, the effect of hydraulic fracturing may be discounted. The physical experiment on hydraulic fracturing propagation in laboratory showed that the penetration of hydraulic fracture into the salutatory barrier mainly depended on the normal stress difference between salutatory barrier and pay zone. The hydraulic fracture could penetrate into the salutatory barrier and propagate in original direction under the normal stress difference of about 4 MPa. The dimensionless net pressure, difference of Yang＇s modulus and fracture toughness between reservoir and salutatory barrier also affected the behaviors of hydraulic fracture. The hydraulic fractures crossing the salutatory barrier need a lot of energy accumulation, which can lead to a notable fluctuation of pressure curve.

关 键 词：水力压裂 突变体 裂缝延伸 法向应力差 产层 断裂韧性 实验研究 

分 类 号：TE357.11[石油与天然气工程—油气田开发工程]