鄂尔多斯盆地富县页岩气缝网压裂适应性研究

Study on Adaptability of Shale Gas Network Fracturing in Fuxian,Ordos Basin

页岩气开发是近几年国内外研究的热点,缝网压裂是目前页岩气开发的主要技术手段.对比分析了美国页岩气与富县延长组页岩气成藏条件,认为鄂尔多斯盆地富县区块延长组长7段具有页岩气开发的潜力.进行了富县与美国各大盆地岩石矿物组成对比分析研究,分析了石英、长石、黏土矿物等组分对缝网形成条件的影响,确定富县区块延长组长7段储层进行缝网压裂的可行性.通过杨氏模量和泊松比计算出长7段页岩脆性范围为54.3％～67.4％,对比结果表明富县延长组长7段页岩使用缝网压裂能够形成较为复杂的网状裂缝；在此基础上,针对富县区块延长组长7段的储层特征提出了缝网压裂的初步方案,即使用低黏度压裂液和低密度支撑剂,大液量、大排量、小粒径和低砂比的压裂工艺,在页岩中形成大规模的裂缝网络,提高油气动用程度,扩大可采储量,对富县区块延长组长7段页岩气改造具有一定的指导意义.

Development of shale gas is one hotspot in recent years and network fracturing is the main technology currently. The reservoir forming condition of shale gas in America and Fuxian Yanchang Formation is compared and identified the development potential of shale gas in Chang-7, Yangchang formation, Fuxian block, Ordos Basin. According to the studying of composition influence of quartz, feldspar, clay mineral to network fracture formation, network fracturing feasibility in Chang-7 formation was confirmed by analyzing comparison of rock compositions be- tween Fuxian block and basins in America. Shale brittle in Chang-7 formation were calculated by young~ modulus and poisson~ ratio with range of 54.3% -67.4%. According to the study, network fracturing in Chang-7 shale for- mation can form complicated network fracture. Preliminary plan of network fracturing in Chang-7 formation was pro- vided in this paper. It can form large scale network fracture by usage of fracturing technology with low-viscosity fracturing fluid, low-density proppant, large liquid volume, high flow rate, small particle and low sand ratio. This will help to improve producing degree of oil and gas and to increase recoverable reserves which provided guidance of stimulation in Chang-7, Yangchang formation, Fuxian block.