摘要
为了认清致密砂岩气运移特征,选取人工岩心以及川西地区须四段致密储层岩心样品,利用核磁共振在线测试平台,建立一套适用于气体驱替实验的核磁共振研究方法,并开展致密砂岩内气体运移模拟实验。实验结果显示:当充注压力大于临界注入压力时才能发生气体的充注,且临界注入压力随渗透率的减小而成指数倍数增加。致密岩心中气体仍以较大孔隙为主要的运移路径,当渗透率降低至0.1×10^(-3)μm^2以下时,注入压力较大,气体优势运移的现象不十分明显,部分小孔隙中也发生气体运移,近于表现为"弥漫式"或"活塞式"的运移路径特征。在持续低速供气的条件下最终含气饱和度与ΔP/K成正比。
In order to understand the migration characteristics of tight sandstone gas, through the selection of artificial core samples and tight reservoir core samples of the four member of Xujiahe Formation in West Sichuan, using nuclear magnetic resonance online test platform,a set of NMR methods suitable for gas displacement experiments was established, and simulation experiments of gas migration in tight sandstone were carried out.Experimental results showed that gas injection could be implemented only when the injection pressure was greater than the critical injection pressure,and the critical injection pressure increased exponentially with the decrease of permeability.Larger pore was still the main migration pathway for gas in dense rock core,when the permeability was decreased to below 0.1 ×10^-3μm^2 ,injection pressure was higher,gas migration phenomenon was not very obvious, gas migration also occurred in some small pores, closed to the performance as the characteristics of ＂diffuse＂ or ＂piston＂ migration path. Under the condition of continuous low velocity gas supply, the final gas saturation was proportional to AP/K.
出处
《甘肃科学学报》
2017年第4期22-27,共6页
Journal of Gansu Sciences
基金
国家自然科学基金"典型致密砂岩天然气运移机理及成藏机制研究"(41372151)
关键词
致密砂岩
核磁共振
气驱水实验
天然气运移
临界注入压力
Tight sandstone
NMR
Gas drive water experiment
Natural gas migration
Critical injection pressure
