Abstract：Professor Amos M. Nur thinks that raise of oil recovery ratio in an old oil field is increasingly more important than the discovery of new oil field because of the facts that 10% raise of oil recovery ratio in present American ail fields means the discovery of new fields whose oil reserves are equal to those in present American oilfields, and that only limited oil reserve in sand reservoir can be taken out, about 80% oil reserve remaining undeveloped. In order to promote improvement of oil recovery ratio, the author detailedly describes the professor's research results relating to reservoir lithology interpretation and seismic monitor of oil recovery ratio. Professor Amos M. Nur believes that seismic monitor shouldn't only involve heat ail recovery because not only CO2 injecting great changes wave velocity but also water injecting causes wave velocity anomaly which can be found by 3D seismic survey. Water injection is the widest used method far raising oil recovery ratio. Seismic monitor of water injection will bring great economic benefit to oil industries.
