Abstract: Horizontal well is an important technology to develop oil reservoir with bottom water, delay the water breakthrough of oil well and improve the oil recovery rate. However, it is diffi-cult to control and forecast the production performance of oil well after water breakthrough. In this paper we present a sim-plified physical model to develop oil reservoir with bottom water by drilling horizontal wells. On the basis of the previous model,we’ve put forward a practical approach to forecast the produc-tion performance of a horizontal well after water breakthrough in oil reservoir with bottom water and have developed the corre-sponding application software. The prediction data of Renqiu oil
field goes well with the real production data. It shows that the approach presented in this paper is both satisfactory and practi-cal.

Key words: horizontal well, oil reservoir with bottom wa-ter, performance survey, approach