摘要
通过对湘西北地区实地勘察及采样分析,对湘西北下寒武统牛蹄塘组页岩储层的宏观和微观参数对可压裂性的影响进行评价;基于SEM技术与Image J软件相结合的方法,实现页岩孔裂隙率的定量评价;采用组合赋权法建立可定量评价研究区页岩储层可压裂性的可压裂系数数学模型。研究结果表明:研究区下寒武统牛蹄塘组页岩具有脆性矿物质量分数高、脆性系数高、热演化程度高、微孔裂隙较发育的特点,具备页岩储层压裂的有利条件;运用可压裂系数模型计算研究区页岩储层的可压裂系数为0.504 0,咸丰、龙山、桑植和慈利的可压裂系数较高,是研究区页岩较理想的压裂区域;基于储层各参数特征,将研究区的页岩可压裂性分为3个级别,即可压裂性差(可压裂系数小于0.277 4,压裂效果差)、可压裂性中等(可压裂系数为[0.277 4,0.436 3],压裂效果一般)和可压裂性好(可压裂系数为(0.436 3,0.653 8],缝网压裂效果较理想),应选择可压裂系数大于0.436 3的页岩层进行水力压裂。
The effect of macro and micro parameters on fracability of Lower Cambrian Niutitang shale of northwestern Hunan was evaluated based on field investigations and sample analysis. The quantitative evaluation of fractured rate of shale was achieved by combining SEM technique and Image J. A mathematical model based on the combination weight method was established to quantitatively evaluate the shale fracability. The results show that the Lower Cambrian Niutitang formation shale in the study area has great content of brittle mineral, high brittleness index, high degree of thermal evolution and well developed micro-fractures and pores, possession of advantageous conditions for the fracturing of shale gas reservoir. The fracability of the shale Lower Cambrian Niutitang is 0.504 0. And the optimum area for fracturing in the Niutitang Formation shale is Xianfeng, Longshan, Sangzhi and Cili due to their relatively higher fracability indexes. Besides, shale fracability can be divided into three levels according to the reservoir parameters. The shale with low fracability（fracability index is less than 0.277 4） cannot be stimulated effectively. Shale with the medium fracability（fracability index range is [0.277 4, 0.436 3] can be stimulated effectively but the effect is actually modest. Shale with high fracability（fracability index range（0.436 3, 0.653 8] is the best interval to be fractured. It is better to choose shale with fracability index above 0.436 3.
作者
吴晶晶
张绍和
曹函
孙平贺
WU Jingjing1, 2, 3, ZHANG Shaohe1, 2, 3, CAO Han1, 2, 3, SUN Pinghe1, 2, 3(1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Ministry of Education （Central South University）, Changsha 410083, China; 2. Key Laboratory of Non-ferrous Resources and Geological Hazard Detection, Changsha 410083, China; 3. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2018年第5期1160-1168,共9页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(41302124)
有色金属成矿预测与地质环境监测教育部重点实验室(中南大学)开放基金资助项目(2016YSJS009)~~
关键词
湘西北
页岩气储层
下寒武统牛蹄塘组
组合赋权法
可压裂性评价
northwestern Hunan
shale gas reservoir
Lower Cambrian Niutitang
combination weight method
fracability evaluation
