构造物理模拟和PIV有限应变分析对构造裂缝预测的启示  

Structural Analogue Modeling and PIV Finite Strain Analysis:Implications to Tectonic Fracture Prediction

作　　者：沈礼[1,2] 贾东[1] 尹宏伟[1] 魏东涛[2,3] 陈竹新[4] 孙闯[1] 崔键[1] 

机构地区：[1]南京大学能源科学研究院地球科学与工程学院,南京210023 [2]中国石油天然气集团公司油藏描述重点实验室,兰州730020 [3]中国石油勘探开发研究院西北分院,兰州730020 [4]中国石油勘探开发研究院,北京100083

出　　处：《高校地质学报》2016年第1期171-182,共12页Geological Journal of China Universities

基　　金：江苏省科技项目(BE2013115);国家科技重大专项(2011ZX05009-001;2011ZX05003-002)联合资助

摘　　要：油气储层中构造裂缝发育与有限应变状态关系密切,为了探索有限应变分析与构造裂缝预测的新技术方法,此次研究设计完成了一组单侧挤压收敛模型的物理模拟实验,并引入粒子图像测速（PIV,Particle Image Velocimetry） 技术对实验过程进行了定量化分析.实验模型在垂向上为含粘性层的多层结构,实验结果形成了一个肉眼可见的箱状褶皱.通过PIV技术可以获取实验模型变形演化过程中各阶段的位移场数据,计算出各阶段的增量应变,实现从初始状态到褶皱形成之后整个变形过程的有限应变分析,探讨构造裂缝成因机制和分布规律,进行定量化裂缝预测.挤压变形过程初期,应变分布范围很广,有限应变较弱（约4%-8 %）,在挤压方向上的线应变表现为弱压应变,在垂向上的线应变表现为弱张应变,这种现象是褶皱和断层产生前平行层缩短和层增厚的纯剪变形结果,也是区域型张裂缝和剪裂缝形成的主要机制.褶皱和断层即将发育之时至发育之后,应变局限在断层发育的剪切带及附近区域,有限应变表现为较强（达20%） 的剪切应变和剪切张应变,是断层面附近简单剪切变形作用的结果,也是局部型剪裂缝和张剪裂缝形成的主要机制.The development of structural fractures and finite strain state are closely related in the oil and gas reservoir. In order to explore a new method of finite strain analysis and structural fracture prediction, this study designed and performed a set of sandbox experiments. The particle image velocimetry (PIV) technique was applied to quantitatively analyze the experimental process. The experimental model was a unilateral indentation model with a viscous layer in the vertical direction, and the results represent a macroscopic box fold. Using the PIV technique, we can obtain the displacement field data during the deformation process in each stage of the experiments, calculate the incremental strain in each step, and analyze the finite strain state during the whole deformation process from the initial stage to the time after the fold was formed. Furthermore, the genesis mechanism and distribution can be discussed to quantiatively predict the fractures. At the beginning of the deformation, the finite strain was weak (about 4-8%) and widely distributed. Weak compressive linear strain was represented in the direction of indentation and weak tensile linear strain in the vertical direction. These phenomena were interpreted as the results of the pure shear deformation, such as the thickening and parallel shortening of the layers before the folding and faulting initiated. It is also the main mechanism of the formation of the regional tension fissures and shear cracks. The finite strain was localized in the fault zone and the adjacent area when the fold and fault formed. Strong shear and tensile shear strain (up to 20%) was revealed. These were the results of the simple shear deformation along the fault plane. It is also the main mechanism of the formation of the local shear fractures and tensile shear cracks.

关 键 词：物理模拟 粒子图像测速(PIV) 有限应变分析 构造裂缝预测 

分 类 号：P618.13[天文地球—矿床学]