四川盆地威远地区龙马溪组页岩储层上下亚段脆性差异

Brittleness comparison between upper and lower sub-sections of Longmaxi Formation shale reservoir in Weiyuan Area, Sichuan Basin

 陆益祥¹ 潘仁芳¹ 唐小玲² 武文竞¹ 鄢杰¹

油气资源与勘查技术教育部重点实验室（长江大学），湖北 武汉 430100 中国石油华北油田公司勘探开发研究院，河北 任丘 062552）

MOE Key Laboratory of Exploration Technologies for Oil and Gas Resources, Yangtze University, Wuhan 430100, China Research Institute of Exploration and Development, Huabei Oilfield Company, PetroChina, Renqiu 062552, China)

页岩气的开发对于页岩储层的脆性有一定要求。现今,我国页岩气的重点勘探开发层位位于四川盆地下志留统龙马溪组。前人研究表明，龙马溪组具有明显的二分性，其上段和下段页岩储层脆性存在差异。目前，针对这方面的研究还比较少,笔者拟从矿物组分含量分析、脆性指数、弹性模量、泊松比、三轴压力实验等方面来比较龙一段和龙二段的储层脆性差异。结果表明：龙一段比龙二段的脆性矿物含量更高，且脆性指数较大；相比龙二段,龙一段的岩石物理特征是弹性模量更高,泊松比更低；岩心的三轴压力实验表明, 龙一段的应力—应变负坡曲线的斜率的绝对值较大。综合以上结论可以得出,龙一段的脆性要比龙二段好，开发压裂效果更好。

 The development of shale gas has a certain demand for the brittleness of shale reservoir. Today, shale gas exploration and development focuses on the Lower Silurian Longmaxi Formation in Sichuan Basin, China. Previous studies showed that the Longmaxi Formation has two different properties obviously, and the brittleness of the upper and lower sections of Longmaxi Formation shale reservoirs are different. At present, few researches are focused on this aspect. The author intends to analyze the composition of the mineral, the brittleness index, Young′s modulus, Poisson′s ratio, and the three axis pressure to compare the difference of brittleness between the Long 1 and Long 2. The results show that the content of brittle mineral of Long 1 is higher than that of Long 2, so is the brittle index; comparing with Long 2, Young′s modulus of the Long 1 is higher and Poisson′s ratio is lower; three axis pressure test shows that the absolute value of the slope of stress-strain curve for Long 1 is larger. Comprehensive conclusion is that the brittleness of Long 1 is better than that of Long 2, which has a better fracturing effect.

10.6056/dkyqt201604005