SMA强凝胶封堵裂缝性砂岩性能研究

SMA强凝胶封堵剂由主剂、交联剂和延缓剂组成,调节延缓剂用量可以控制其成胶时间(12~144 h).用人造岩心进行凝胶性能实验,50℃时成胶时间为72 h,岩心封堵率大于99.9%,注水50 PV后仍不低于99.8%,突破压力梯度一般不低于3.4 MPa/m.在玻璃填砂裂缝模型封堵实验中,可以清楚地看到SMA强凝胶可以有效地封堵裂缝,后续注入水液流改向,波及面积明显扩大.最后在SMA强凝胶封堵裂缝性长岩心驱油实验中,可以大剂量地注入SMA溶液,成胶后可以长时间地封堵裂缝,增加后续注水的利用效率,在初始水驱的基础上提高原油采收率31.7%.

Experimental study on sealing fractured sandstone using SMA hard-gel

SMA hard-gel sealing agent is made up of host-compound,cross-linking agent and delay agent.The gelation time of the hard-gel sealing agent can be controlled by adjusting the dose of the delay agent.The performance experiments of the gel are made with man-made cores,and the results show that the gelation time is 72 h at 50℃;The sealing ratio of the gel sealing agent is greater than 99.9%,and it is not also lower than 99.8% after the water of 50 PV is injected;The breakthrough pressure gradient is not lower than 3.4 MPa/m usually.The visual fracture-sealing experiment is made with glass sandpack column,and it is obviously observed that SMA hard-gel can effectively sealing the fractures,the sequential injected water changes its direction,and its swept area evidently increases.In the sealing experiments with long man-made cores, a great amount of SMA solution is injected,and fractures can be blocked for a long time,which improves the utilization efficiency of the sequential injected water and oil recovery factor can been enhanced by 31.76% based on the recovery factor of initial water flooding.