孔隙型小层间强非均质碳酸盐岩油 藏注水优化方法

为改善伊拉克AHDEB复杂孔隙型碳酸盐岩油藏Khasib层小层间强非均质性导致水平井注水水窜、波及体积较小等问题,在油藏注水突破机理研究基础上,进行了注采评价优化方法研究。依据水平井井轨迹纵向穿行储层及生产特征情况,划分了3类特征井,并根据其不同生产阶段的生产特征定义了5个评价指标：历史生产因子(IDH)、剩余储量因子(IDR)、生产潜力因子(IDF)、注水需求因子(IDI)和提液生产因子(IDE),建立了单井注水生产分级雷达综合评价图版,定量表征了水平井在不同生产阶段的生产能力,结合地层压力变化数据可实时指导油藏注水优化。结果表明,该图版可以合理评价Khasib层单井注水开发效果,单井调整后生产效果良好,研究结果为实施“一井一策”的差异化精细注水提供有力支持。

Water Injection Evaluation and Optimization of Horizontal Wells in Pored Carbonate Oil Reservoir with Strong Vertical Heterogeneity

In view of the rapid water channeling and low coverage rate of horizontal wells caused by strong vertical heterogeneity in pored carbonate oil reservoir in AHDEB of Iraq, the study of injection-production evaluation and optimization have been done based on the study of water break through mechanism. Producers have been characterized into 3 types depending on the horizontal well trajectory through the reservoir. Meanwhile 5 evaluation indexes have been defined of different production phase (historical reserves utilization index(ID_H), remaining reservoir potential index(ID_R), future productivity index(ID_F), water-injection demand index(ID_I) and liquid production potential index(ID_E)). These indexes would be presented as evaluation charts by the gradational radar chart to characterized the productivity capacity of horizontal wells quantitatively. It shows that this method can also give guidance to water injection optimization and rapid reservoir regulation combined with formation pressure data. The method have a good application to Khasib formation of Ahdeb oilfield in Iraq, which can reasonably evaluate the single well water-flooding development capacity. Adjusted production efficiency was accordance to prediction data, the results would give a technical support to reservoir fine differential water-flooding.