页岩储层Ⅰ型和Ⅱ型断裂韧性评价方法研究  

DETERMINATION OF FRACTURE TOUGHNESS OF MODES Ⅰ AND Ⅱ OF SHALE FORMATION

作　　者：陈建国[1] 邓金根[1] 袁俊亮 闫伟[1] 蔚宝华[1] 谭强[1] 

机构地区：[1]中国石油大学油气资源与探测国家重点实验室,北京102249 [2]中海油研究总院,北京100027

出　　处：《岩石力学与工程学报》2015年第6期1101-1105,共5页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51174219)

摘　　要：岩石断裂韧性对于定量评价页岩储层可压裂性具有重要意义。基于此,根据直缝切槽巴西圆盘实验(SNBD),测定了14块龙马溪组储层页岩的Ⅰ型(张开型)、Ⅱ型(划开型)断裂韧性。并利用上述实验结果,结合岩心所处深度处的测井数据,选择密度、声波时差、GR测井数据回归了页岩的断裂韧性。与前人基于抗拉强度建立的断裂韧性预测模型相比,建立断裂韧性与地球物理测井数据的直接联系。由预测模型可以看出,富有机质页岩Ⅰ型和Ⅱ型断裂韧性均与岩石密度、声波时差成正比,与页岩泥质含量成反比。即页岩中有机质(TOC)含量或黏土矿物越多,页岩断裂韧性越小,页岩起裂后越容易向前延伸。结果表明,计算断裂韧性与实测断裂韧性相关性较好。模型的建立可以为工程设计过程中找出"甜点"提供重要理论依据。Fracture toughness of rock is one of the most important factors for evaluating the fracturing of shale reservoir quantitatively. The fracture toughness of modes Ⅰ and Ⅱ of fourteen shale samples from Longmaxi formation were measured based on the straight seam grooving Brazilian disc test(SNBD). Based on the above results and the logging data, an analysis of regression of the shale fracture toughness was made in terms of the density,the acoustic time and GR logging. Compared with the prediction model based on the tensile strength,a direct relationship between the fracture toughness and the geophysical logging data was established. According to the prediction model,the fracture toughness of the organic-rich shale is proportional to the density and the phase difference of the acoustic time of rock and is inversely proportional to its shale contents. The more the total organic carbon(TOC) or clay mineral, the smaller the fracture toughness and the easier crack extension. The results indicated that the fracture toughness of predication model had a good correlation with the measured data from SNBD.

关 键 词：岩石力学 直缝切槽巴西圆盘 Ⅰ型和Ⅱ型断裂韧性 地球物理测井 水力压裂 

分 类 号：TE311[石油与天然气工程—油气田开发工程]