低渗气藏启动压力梯度研究与分析

The study and analysis of starting pressure gradient in low permeability gas reservoirs

依呷 唐海 吕栋梁

Yi Ga Tang Hal Lv Dongliang

西南石油大学研究生院, 四川成都 610500

Southwest Petroleum University, Chengdu 610500, China

在低渗透气藏中,气体渗流是否存在启动压力梯度以及启动压力梯度存在条件一直是石油工作者研究和争论的焦点之一。通过一系列实验,研究了低渗透气藏中气体渗流存在启动压力梯度的条件,获得了气藏有效渗透率大于0.1×10-3μm2或束缚水饱和度低于20%时,不存在启动压力梯度;并定量化了启动压力梯度与束缚水饱和度之间的关系。

In the gas reservoirs with low permeability, whether there is starting pressure gradient or not and the qualification of starting pressure gradient appearance in the gas seepage is always one of the debate focus among the petroleum researchers. This article presents a series of experiments to obtain the qualification of starting pressure gradient appearance in the gas reservoirs with low permeability, and concludes that when the permeability of gas reservoirs is bigger than 0.1×10-3μm2 or the irreducible water saturation is less than 20%, there isn't starting pressure gradient. This paper also presents the formula between the starting pressure gradient and irreducible water saturation.