底水油藏高含水水平井注N2实验与参数优化

Experiment research and parameter optimization of N2 huff and puff for watered-out horizontal well in bottom water reservoir

 李亮¹ 张建军¹ 林森² 汪国琴²

中国石化西北油田分公司石油工程技术研究院，新疆 乌鲁木齐 830011 长江大学石油工程学院，湖北 武汉 430100）

Engineering Research Institute, Northwest Oilfield Company, SINOPEC, Urumqi 830011, China Petroleum Engineering College, Yangtze University, Wuhan 430100, China)

 在深入调研N₂吞吐工艺的基础上，针对塔河油田实际情况建立了塔河9区TK907井模型，最大程度地还原了储层的真实情况。首先，进行衰竭式生产，当压力降到20 MPa时，进行底水驱形成底水脊进；当底水侵入到水平段、含水率上升到一定程度后，注入N₂进行吞吐。实验结果表明，对底水油藏中高含水水平井进行N2吞吐后，能使采收率提高10.0~20.0百分点。同时得到以下认识：1）N₂吞吐具有良好的压脊作用；2）吞吐中有明显的毛细管力滞后现象；3）含水率为80%时，是注入N₂的最佳时期；4）在不超过地层破裂压力的情况下，注气量、注气速度和焖井时间这3个参数越大越好；5）影响N₂吞吐效果的因素从大到小排序为注气量、焖井时间、注入速度、注气时机、地层压力恢复水平。

In this paper, based on the in-depth research of N2 huff and puff technology and actual situation of the Tahe Oilfield, the model of TK907 well was built to show the maximum actual circumstance of the reservoir. The experiment process is that: depletion production is carried out before the pressure drops to 20 MPa, then the bottom water drive is performed to form a bottom water coning. When water invades the horizontal section and the water rate increases to a certain extent, N2 is injected into the well. Experimental results show that N2 huff and puff will increase recovery rate about 10.0%-20.0% for high water-cut wells in bottom water reservoir. The following understanding can also be obtained: good function of reducing the level of water back, the phenomenon of the capillary force hysteresis; the water content of 80% is the optimal period for N2 injection; within the limit of formation fracture pressure, the more gas injection volume, the bigger gas injection rate, longer soak time are appreciable; the sequence of N2 huff and puff influencing factors is gas injection volume, soak time, gas injection rate, gas injection time, and recovery level of formation pressure.

10.6056/dkyqt201603018