薄油层火驱开发井网形式选择及注气策略优化

Well pattern selection and gas injection strategy optimization for the fire flooding of thin reservoirs

宋清新

SONG Qingxin

胜利油田滨南采油厂

Binnan Oil Production Plant, Shengli Oilfield Company, Binzhou 256600, Shandong, China

火烧油层是薄层油藏开发的有效技术之一。结合某低渗薄层区块的实际地层情况，采用数值模拟方法探究了多种因素对低渗薄层油藏火驱开发的影响，给出了油墙掠过生产井时刻的判别方案，并优化出了最优生产参数。研究结果表明，排状井网相比于左起井网和反九点井网采收率更高、生产更平稳，但热联通更慢；井距在70~141 m区间变动时，采收率随井距增加而降低；单侧生产井数量多于一排时，选择生产井产气中氧气含量突增的时刻关井较为合理；对低渗薄层油藏而言，注气开孔位置对采收率的影响并不明显，在注气量达到25 000 m³/d后，继续增加注气量对采收率的改善效果不明显。推荐最优生产参数为70 m中央排状井网，注气井上部开孔，注气量25 000 m³/d。

In-situ combustion is one of the effective technologies for the development of thin reservoirs. In this paper, the influences of different factors on the fire flooding of low-permeability thin reservoir were discussed by means of numerical simulation, based on the actual formation conditions in one certain low-permeability thin layer block. In addition, the scheme for discriminating the moment when the oil bank sweeps past the production well was prepared, and the optimal production parameters were determined. It is indicated that compared with nine-spot well pattern and inverted nine-spot well pattern, row well pattern provides higher recovery factor and more stable production, but its thermal communication is slower. When the well spacing is in the range of 70-141 m, the recovery factor decreases with the increase of well spacing. When the number of production wells on one side is greater than that in one row, it is more rational to shut down the well the moment the oxygen content of produced gas of production well rises suddenly. For low-permeability thin reservoirs, the recovery factor is less influenced by the hole opening position of gas injection. After the gas injection rate reaches 25 000 m/d, the recovery factor will not be improved greatly with the further increase of gas injection rate. The optimal production parameters are recommended as 70 m central row well pattern, hole opening in the upper part of gas injection well and gas injection rate of 25 000 m/d.

10.13639/j.odpt.2021.05.011