缩小井距结合聚合物驱提高边际油层采收率研究

陆相、多层、非均质砂岩油田部分油层因发育连续性差、渗透率低、层间渗透性差异大,造成现井网水驱控制程度低和层间干扰严重,致使水驱采收率低。由于进一步加密井网进行水驱开采经济上不可行,为此提出了井网加密和聚合物驱结合的方法,并开展了先导性矿场试验。室内聚合物注入参数研究、方案设计优化、聚合物驱动态特征、分层注入工艺以及增产、增注措施的研究表明,在井距缩小到100 m的条件下,将厚度小于1 m、渗透率界于5×10-3~100×10-3μm2的油层组合,通过分层注聚、分质周期注聚,可提高采收率10%以上。结果表明,井网加密和聚合物驱技术结合经济可行。

Combining small well spacing with polymer flooding to improve oil recovery of marginal reservoirs

The recovery factor of water flooding is very low in some continental and heterogeneous sandstone oil fields,especially when the reservoir continuity is poor,permeability low and high permeability variation between different zones.Because the amount of incremental producible oil is not large enough to further drill infill wells economically,drilling infill wells and performing polymer flooding simultaneously was proposed and a pilot test has been conducted.This paper introduces the laboratory studies on selection of polymer injection parameters and project design optimization.Under well spacing of 100 m,the zones with a thickness of less than 1m and with a permeability range of 5 to 100 md were combined together and put on development.Both lab studies and pilot results show that the recovery factor has over 10% increase,especially after applying separate zone injection measures in polymer injectors.The pilot test indicates that the technique of combining infill wells with polymer flooding is economically feasible.