低渗气藏特殊渗流机理实验研究

EXPERIMENTAL STUDY ON SPECIAL PERCOLATION MECHANISM OF LOW-PERMEABILITY GAS RESERVOIR

通过实验研究不同含水饱和度下岩心的渗流特性,解决了滑脱效应与启动压力相矛盾的问题,结果表明:在低含水饱和度下,岩心中气体渗流主要受滑脱效应的影响;而在高含水饱和度下,则主要受启动压差的影响。用误差更小的回归法计算出不同含水饱和度下的启动压力,并在其它条件不变的前提下,按比例改变岩心的长度,结果启动压力(梯度)的改变却不成比例,由此认为仅利用启动压力梯度计算井距这一方法并不合理。

The contradictory problem between start-up pressure and slippage effect is solved by experimentally studying the percolation behavior of core at different water saturation. The results show that the gas percolation in core is mainly affected by slippage effect at low water saturation whereas it is mainly affected by start-up pressure difference at high water saturation. Start-up pressure at different water saturation can be calculated by regression method with less error. When the other conditions are constant,start-up pressure (gradient) varies disproportionally with the change of core length. It is therefore believed that one method which uses just start-up pressure gradient to calculate well spacing is unreasonable.