渤海LD5-2稠油油藏非均质性较强、岩石胶结强度较低,长期注水开发已经形成了优势通道。目前,单一调剖、调驱或驱油措施很难满足大幅度提高采收率的要求,将调剖、调驱和驱油等措施联合使用成为解决这一瓶颈的新思路。为满足LD5-2油藏的实际需求,该实验利用纵向三层非均质岩心及“分注分采”新型模型,借助电极测量等手段,开展了“调剖+调驱+驱油”复合调驱室内实验研究。结果表明,与直井井网相比较,水平井井网调剖后中低渗透层吸液压差较大,扩大波及体积效果较好,采收率增幅28.50 %。对于非均质岩心,调驱后剩余油纵向上主要分布在中低渗透层。平面上,直井井网主要分布在远离主流线的两翼部位,水平井井网油水界面则平行于井眼轨迹。“复合凝胶+微球/高效驱油剂”段塞组合中,复合凝胶在高渗透层内滞留作用较强,液流转向效果较好,使得后续“微球/高效驱油剂”2者之间的协同效应得以较好发挥,这兼顾了扩大波及体积和提高洗油效率技术需求,因而增油降水效果明显,采收率增幅26.50 %。复合调驱是大幅度提高采收率的关键。

Bohai LD5-2 heavy oil reservoir has strong heterogeneity and low rock cementation strength. It has formed a dominant channel due to long-term water injection. At present, it is difficult to meet the requirements of greatly improving oil recovery by single profile control, flooding or oil displacement measures. The combined use of profile control, displacement and other measures has become a new way to solve this bottleneck. In order to meet the actual demands of LD5-2 reservoir, in-room experimental study of profile modification measure of “profile control+profile modify+oil displacement” is carried out by the longitudinal three-layer heterogeneous core and a new model of “injection and production separately” and the means of electrode measurement. The results show that, compared with the vertical well network, the hydraulic pressure difference of the mid-low permeability layer is larger after the horizontal well network profile adjustment, the effect of expanding the spreading volume is better, and the recovery rate increases by 28.50 %. For the heterogeneous cores, the remaining oil in the longitudinal direction is mainly distributed in the mid-low permeability layers. On the plane, the vertical well pattern is mainly distributed in the two wings away from the main stream line, while the horizontal well network oil-water interface is parallel to the well trajectory. The composite gel in the slug combination of “composite gel+microsphere/high efficiency oil displacing agent” has a strong retention effect in the high permeability layers. The liquid flow steering effect is better, which makes the synergistic effect in the subsequent “microsphere/high efficiency oil displacing agent” composite system better. It takes into account the technical requirements of expanding the volume and improving the washing efficiency, and the effect of increasing oil and precipitation is obvious, with the increase of recovery rate by 26.50 %. Profile modification is the key to increase oil recovery greatly.