重新认识河道砂体储层层内非均质性——从注水开发高含水阶段挖掘层内剩余油潜力谈起

Recognition of reservoir intraformational heterogeneity in channel sandbodies——To tap potential of remaining oil at high water-cut stage of waterflooding oilfields

根据我国东部主力油田储层绝大多数都属于河道砂体,注水开发进入高含水阶段后,层内剩余油超过层间剩余油,层内矛盾上升为主要矛盾这一特点,从挖掘层内剩余油潜力出发,提出要重新认识河流砂体储层层内非均质性,并指出高含水期河流砂体储层改善采油(IOR)目标主要有:①封堵强水洗段,控制注入水无效循环;②加大中水洗段注水冲洗强度,达到目标水驱效率,并有可能超过目标效率;③提高未、弱水洗段的注采对应程度和注采井数比,达到有效驱替,提高波及程度。围绕这些目标,通过例证提出重新认识河流砂体层内非均质性设想建议和研究方向。

In view of the fact that most of reservoirs of major oilfields in eastern China are composed of channel sandbodies and at high water-cut stage, waterflood development aggravates the intraformational contradiction by leading to more intraformational remaining oil than intefformational ones. Therefore, tapping potencial of remaining oil to improving oil recovery （IOR） , the recognition of reservoir intraformational heterogeneity in channel sandbodies is proposed and the main targets of reservoir IOR in channel sandbodies of mature oilfields are pointed out as follows： ①shutting off strongly-waterflooded intervals to control ineffective circulation of injected water; ②strengthening water washing in medium-waterflooded intervals in order to achieve the aimed waterflood efficiency and even to exceed it; ③enhancing injection-production consistency and injector-producer ratio of non-waterflooded or weakly-waterflooded intervals for the propose of realizing effective displacement and imporving conformance. Around these targets mentioned above, the research orientation and tentative recommendations about recognition of intraformational heterogeneity in channel sandbodies are proposed by exemplification.