Following long-term waterflooding,the sandstone reserv oir has variable spontaneous poten-tial(SP)resulted from variable electrofilt ration potential which is closed with the pressure drawdown.

• 经长期注水开发的砂岩储集层,自然电位的变化主要由过滤电位的变化所引起,而过滤电位与压差密切相关,由此引出了应用自然电位解释孔隙压力方法。