摘要
针对海上平台寿命有限、平台空间狭小、聚驱产出液处理困难等特点，提出应用非均相调驱技术提高采收率的思路。利用纵向三层非均质物理模型，考察了水驱后、聚驱后、二元复合驱后不同非均相体系驱油效果，结合驱替后岩心剩余油分布情况，分析非均相调驱与常规聚合物驱在驱油机理上的差异。研究结果表明：无论是水驱后、聚驱后、二元复合驱后，非均相调驱都能大幅度提高采收率，采收率增加值分别在6.95%、9.57%、11.46% 以上；在相同浓度非均相体系条件下，先溶胀后注入和先注入后溶胀2 种不同注入方式驱油效果基本一致，说明体系在岩心内可以达到与室内静态评价溶胀相同的效果；分散相粒径大小对于驱油效果的影响至关重要，大颗粒偏重于“调”，小粒径偏重于“驱”。聚驱后油藏剩余油分布更加零散，进一步提高采收率的潜力主要在低渗透层，单纯依靠提高驱油体系的洗油效率不足以提高其动用程度，需要进一步扩大驱油体系的波及体积。
Abstract
In view of limited offshore platform life, small space of platform and difficulty in treating the polymer flooding produced fluids, this paper introduces the idea of EOR using heterogeneous profile control and flooding technology. Using longitudinally 3-layer heterogeneous physical model, the oil displacement effects by different heterogeneous systems were investigated after water flooding,polymer flooding and SP flooding; in combination with remaining oil distribution in cores after displacement, the difference of heterogeneous profile control and flooding and conventional polymer flooding was analyzed in oil displacement mechanism. Research results show that, the heterogeneous profile control and flooding can greatly enhance oil recovery after water flooding, polymer flooding and SP flooding, which enhance values are over 6.95%, 9.57% and 11.46% respectively. Under the heterogeneous system of the same concentration,two injection methods –injection after swelling and swelling after injection – are almost the same in oil displacement effect,indicating that the system can achieve the same effect in cores as in indoor static evaluation swelling and that the particle size of dispersion phase has a very critical effect on oil displacement, where large particles are more meant to “profile control” while the small particles to “flooding”. Reservoir remaining oil distribution after polymer flooding is more scattered, so the potential for further EOP lies mainly in low permeability layer; simply depending on increasing the displacement efficiency of oil displacement systems is not sufficient to improve its production degree, so it is necessary to further expand the swept volume of oil displacement systems.
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