边底水油藏化学驱提高采收率实验研究

Experimental Study on Enhanced Oil Recovery by Chemical Flooding in Reservoir with Edge and Bottom Water

为探索冀东油田高浅南油藏化学驱提高采收率技术,研制适应油藏条件的驱油用表面活性剂,利用均质岩心模型和3层非均质岩心模型开展化学驱驱油实验,对该油藏化学驱提高采收率的可行性进行综合评价。实验结果表明:研制的表面活性剂降低油水间界面张力的能力较强,浓度为0.3%时油水界面张力即可达到10^(-3)mN/m数量级,拥有很强的提高驱油效率的能力;该表面活性剂对高浅南油藏具有较好的驱油效果,可在水驱基础上继续提高采收率15.00个百分点。研究认为,对于冀东油田高浅南油藏,采用单一表面活性剂驱采收率提高幅度较小,而采用调剖堵水+表面活性剂驱技术对提高采收率有明显效果。建议对于非均质性较弱的油藏,提高采收率应以提高驱油效率为主,对于非均质性较强的油藏,提高采收率应以提高波及效率为先。该研究结果对同类油藏提高采收率具有一定的借鉴意义。

In order to explore enhanced oil recovery technology by chemical flooding in Gaoqiannan reservoir of Ji- dong Oihqeld, a surfactant for oil displacement adapted to reservoir conditions is developed, chemical flooding ex- periments are carried out by using homogeneous core model and 3 layer heterogeneous core model, and the feasibili- ty of enhancing recovery by chemical flooding is comprehensively evaluated. Experimental results show that： the of developed surfactaut has strong ability to reduce the interfacial tension between nil and water, when the concentra- tion is 0.3%, the interfacial tension can reach 10-3 mN/m orders of magnitude, which display a very strong en- hanced oil recovery efficiency; this surfactant has good oil displacement effect for Gaoqiannan reservoir, and can in- crease the recovery by 15 percentage points on the basis of water flooding. Research shows that for the Gaoqiannan reservoir in Jidong Oilfield, the recovery was increased slightly with single surfactant flooding, while profile control and water shutoff ＋ surfactant flooding technology has obvious effect on enhancing oil recovery. It is suggested that, for the reservoir with weak heterogeneity, to improve the recovery rate should be mainly to improve oil displacement efficiency, and for the reservoir with strong heterogeneity, mainly to improve sweep efficiency first. The research re- suits have certain significance to improve the recovery of similar reservoirs.