文留油田低渗透砂岩裂缝储层压力敏感性研究

对于文留油田低（特低）渗透砂岩裂缝性储层来说,其独特的孔渗性有别于一般的砂岩或砾岩储层,压敏机理也有所区别。对于一般的砂岩或砾岩储层来说,其所呈现的压敏效应主要是因为喉道趋于闭合或因为泥质挤入造成的渗透率下降。而对于本地区裂缝性储层来说,基质一般较为致密,孔隙度、渗透率极低,其受压力而引起的孔隙度、渗透率性能改变甚为有限。由于压力的改变而引起的储层物性的改变,主要是储层裂缝的开启闭合决定的。进一步研究表明,在裂缝储层中渗透率随压力的变化尤为明显。有效应力变化速度越快,其对岩心渗透率的损害就越强。

Research on pressure sensitivity of fractured sandstone reservoir with low permeability in Wenliu Oilfield

The unique porosity and permeability of the fractured sandstone reservoir with low permeability in Wenliu Oilfield are different from that of common sandstone and conglomerate reservoir.The mechanism of pressure sensitivity is also different.The pressure sensitivity effect of common sandstone and conglomerate reservoir is the result of pore throat closure or permeability drop caused by mud squeezing.For the fractured reservoir in this area,the matrix is generally dense,and the porosity and permeability are low,so the performance change of porosity and permeability by pressure is very limited.The change of reservoir physical property is caused by pressure change,which is determined by fracture open and closure.Further studies show that the changes in permeability with pressure are particularly obvious in fractured reservoir.The faster the change of effective stress is,the stronger its damage to core permeability is.