摘要
深层致密砂岩结构面的力学行为易被忽视。通过岩心物性资料、岩石力学实验分析了孔隙影响岩石破裂的基本特征,确定了岩石破裂的孔隙度下限为2.21%,与研究区储层孔隙度下限2%基本吻合,而物性下限对应的临界抗张强度为6.46 MPa,也与研究区砂岩平均抗张强度基本一致。加载方向平行于纹层时,岩石更易发生破裂。微裂隙力学变形实验表明,存在微裂隙的岩石首次加载-卸载后,平均形变恢复比小于35%,张开度明显减小。该研究从微观角度揭示了岩石结构面对岩石破裂和变形的基本力学行为,可为裂缝控制因素分析、预测及其有效性评价提供重要依据。
The mechanical behavior of structure surface for deep tight sandstone is easily overlooked. Based on core physical property data and rock mechanical experiment, this paper analyzes the basic characteristics of the effect of pore on rock rupture and determines the physical property lower limit of rock rupture to be 2.21%, which is basic consistent with the lower limit of reservoir porosity of 2% in this study area. Its corresponding critical tensile strength is 6.46 MPa, which is also consistent with the average tensile strength of sandstone. When stress loading direction is parallel to the lamina, rock is more likely to rupture. The micro fracture deformation experiments results show that after the first loading-unloading of rock, the average deformation recovery is less than 35% and the degree of opening reduces obviously. The study reveals the basic mechanical behavior of rock structure surface on rock rupture and deformation from microscopic point of view, which can provide important microscopic evaluation basis for the control factor analysis, prediction and effectiveness evaluation of fracture.
出处
《断块油气田》
CAS
2014年第5期560-563,共4页
Fault-Block Oil & Gas Field
基金
中国石化重点科技攻关项目"新场气田须二气藏裂缝特征与分布评价"(G110-10-2S-0038)
关键词
力学结构面
岩石微观力学特征
纹层
微裂纹
孔隙度
mechanical structure surface
micro-mechanical characteristics of reck
lamina
microcrack
porosity
