气顶油藏水平井最优垂向位置研究

Study on optimal vertical position of horizontal well in gas-cap reservoir

吕爱民 姚军

Lv Ai-min YAO Jun

中国石油大学石油工程学院, 山东 东营 257061

College of Petroleum Engineering, China University of Petroleum, Dongying 257061, Shandong, China

水平井开发油藏是避免气顶油藏过早见气的有效手段,而确定水平井最优垂向位置是获得最佳开发效果的关键。针对这一问题,从水平井垂向位置对气顶油藏临界产量和见气时间的影响入手,得出了临界产量和见气时间与水平井垂向位置的关系曲线;在综合考虑临界产量和见气时间的基础上,得到了水平井垂向位置与临界产量和见气时间乘积的关系曲线,由曲线趋势得到了气顶油藏水平井最优垂向位置的范围。研究表明,水平井越靠近气顶,临界产量越大,而见气时间越短;水平井距油气界面的距离为含油厚度的80%~90%时开发效果最优。该研究结果为气顶油藏水平井的油藏工程设计提供了依据。

The horizontal well is an effective way to avoid early gas breakthrough of gas cap reservoir and the identification of its optimal vertical location is the key to obtain the best development result.Through analyzing the effect of the vertical locations of horizontal wells on the critical output and gas breakthrough time of the gas cap reservoir,the curve showing the relationship between the vertical locations of horizontal wells and the critical output as well as the gas breakthrough time is obtained in this paper.After taking both critical output and gas breakthrough time into consideration,the obtains the curve showing the relationship between the vertical locations of horizontal wells and the arithmetic product of critical output and gas breakthrough time.According to the curve tendency,the range of the optimal vertical locations of horizontal wells in gas cap reservoirs is obtained as well.The research shows that the critical output will increase and the gas breakthrough time will become shorter if the horizontal well gets closer to the gas cap.The best development effect will be achieved if the distance between the horizontal well and the oil-gas interface accounts for 80% to 90% of the oil bearing thickness.This can supply basis for reservoir engineering design of the horizontal wells in gas cap reservoir.

10.3969/j.issn.1000-7393.2007.01.029