摘要
借助实际岩心夹片方法,利用显微观察技术,通过实验对油驱水、气驱水的微观运移过程进行分析.研究结果表明,油驱水和气驱水排驱压力均随孔隙度的降低而呈明显增加趋势,统计规律服从幂函数变化规律,但两者之差与孔隙度具有复杂变化关系,形成了代表不同成藏意义的3段曲线.当孔隙度大于10%～12%时,油驱水、气驱水的排驱压力差值较小,形成气藏和油藏的概率几乎均等;当孔隙度大于5%,小于10%～12%时,油驱水、气驱水的排驱压力差值较大,表现为油驱水排驱压力明显大于气驱水,说明储层对石油主要是起封闭遮挡作用,对其运移可能无效,即不能作为油的储层,但可以作为天然气的储层;孔隙度小于5%时,油驱水、气驱水的排驱压力差值较小,毛细管排驱压力对油、气运移具有相同的阻挡作用,油藏和气藏形成难度均较大.实验结果合理地解释了根缘气与根缘油在成藏概率上的差异性,以及致密砂岩作为盖层的机理问题.
Micro-migration process of oil/gas-drive-water has been studied with actual core clip and micro-experiment technology.Research shows that entry pressures of both oil-drive-water and gas-drive-water increase obviously according to porosity decrease.The statistical regularity submits to power function variation regularity.However,there is complex changing relationship between porosity and oil/gas-drive-water entry pressure difference,forming 3 fragment curves with different accumulation significance.When porosity is over 10%-12%,the difference between oil/gas-drive-water entry pressures is small and the probabilities of oil and gas reservoir formation are nearly equal.When porosity is between 5% and 10%-12%,the difference is big,indicating that reservoir can seal hydrocarbon.It is the reservoir for not oil but gas.When porosity is less than 5%,the difference is small and the entry pressures of capillary show the same sealing function for oil and gas.Oil and gas pools are both difficult to form.Experimental results have given rational explanation for the difference of accumulation probability between source-contacting gas and source-contacting oil,and for the mechanism problem of tight sand as cap rock,too.
出处
《石油实验地质》
CAS
CSCD
北大核心
2007年第5期531-534,共4页
Petroleum Geology & Experiment
基金
国家自然科学基金(40472073
40272062)
关键词
油气驱水
排驱压力
显微实验
成藏意义
oil/gas-drive-water
entry pressure
micro-experiment
accumulation significance
