泥页岩气层脆性特征的地球物理测井研究方法

The Interpretation Methods of Geophysical Well Logging for the Brittle Characteristics of Shale Gas Reservoirs

页岩气作为清洁能源在国际上勘探开发技术较成熟,研究手段也很丰富,页岩气层岩石物理特性研究就是其中的关键技术之一。就中国页岩气勘探区块而言,以中国石化焦石坝、高邮凹陷区块较为成功。笔者利用高邮凹陷区块泥页岩气层钻井获得的岩心,在实验室钻取直径2.5cm、长度4-6cm的样本。将饱和水岩样置入HR2500-2高速冷冻离心机,分8种转速脱水模拟岩样不同含水饱和度,再利用CTS-45型非金属超声波检测分析仪模拟地层条件测定泥页岩样的纵横波速度;并利用实验数据得到了泥页岩储层的泊松比、杨氏模量、脆性指数等参数。处理高邮凹陷区块5口井的测井资料,得到ElF4层位的脆性指数,结果发现：泥页岩的杨氏模量越高,泊松比越低;脆性越高,可压裂性越强。总结出E1F4层段各小层可压裂性级别,科学指导了该区压裂设计。

Shale gas as a clean energy development technology is relatively mature in worldwide and its research methods are also abundant. Now rock physical properties of Shale gas reservoirs are one of the key technologies. In terms of Chinese shale gas exploration blocks, Sinopec focal darn and Oaoyou sag block are more successful. Firstly, in the laboratory 5 samples（2.5 cm in diameter, length of 4-6 cm）from the cores are drilled in shale gas layer. Secondly, the saturated water sample is put into HR2500-2 high-speed refrigerated centrifuge, and then 8 kinds of speed dehydration are used to simulate samples in different water saturation. Thirdly, it is placed at simulated conditions of formation to determine p-and s-wave velocity of samples by using the CTS-45 nonmetal ultrasonic testing analyzer. Finally, combining experimental data with the calculation method of rock mechanics param- eters, a series of parameters can be obtained such as Poisson ratio, Young＇s modulus and brittleness index. The results, which get from the above mentioned methods for 5 wells of Gaoyou sag block, show that the higher the Young＇s modulus is, the lower Poisson ratio is. And the higher the brittleness is, the stronger the fracturing performance is. E1F4 inter- val of each small layer fracturing level is summarized, which has scientific guidance on the fracturing design.