关键词: 油基泥浆, 岩石, 润湿性, 驱油效率, 地层损害

Abstract: Using natural sandstone core samples,the effect of wettahlity alteration of reservoirrocks caused by oil-based mud on water flood behavior was studied through establishingmodels of reservoir rocks and simulating the processes of the mud filtrate invasion,displace-ment restoration and water flooding.The test results showed that the increased rate of watercut raised,and both the recovery efficiency and oil production are substantially reduced afterthe sandstOne core were altered from water-wet to oil-wet.It was found that oil-based mudwith stronger oil-wet behavior had more significant effect on recovery efficiency,indicatingthat wettability reversal is an important mechanism of formation damage induced by oil-based completion fluids,Meanwhile,a comparison study on water-based mud and their com-ponets of water flood behavior has been conducted.

Key words: oi-based mud, rock, wettability, oil displacement efficiency, formation damage