特稠油油藏注氮气可行性分析

Feasibility analysis of nitrogen-assisted steam stimulation in super-heavy oil reservoir

杜殿发 郭青 王青 张亮 石达友 姜林

DU Dianfa GUO Qing WANG Qing ZHANG Liang SHI Dayou JIANG Lin

中国石油大学，山东青岛　266555

China University of Petroleum, Qingdao 266555, China

蒸汽吞吐是特稠油油藏开采的主要方法，但随着吞吐轮次增加，地层能量下降，周期产油减少，开采效果变差。结合新疆九7+8 区地质特征，建立理论模型，通过数值模拟对蒸汽吞吐后期采取注氮气改善吞吐效果进行可行性分析，对混氮比、注入时机、注入方式、注入速度等注氮参数进行优选。模拟结果表明，注氮气后单井周期产油量平均提高6146.9 t，含水率平均降低15%。注汽过程中注氮气的方法可在很大程度上改善超稠油的开发效果，为有效开发此类难动用储量提供借鉴。

Steam soak is mainly used to develop super-heavy oil reservoir. With the increase of circulation turns, formationpressure and periodic oil production decrease rapidly, and production effect is poor. This paper builds a theoretical model withintegration of geological characteristics of Jiu 7+8 block in Xinjiang. Then by numerical simulation, it analyzes the feasibility to injectnitrogen at late stage of steam soaking and optimizes the key parameters of mixed nitrogen ratio, injection timing, injection mode,injection rate and so on. Simulation results show that average periodic oil production of single well after nitrogen injection increases6146.9 ton，water cut decreases 15%. To inject nitrogen during steam soaking can improve development effect of super heavy oilreservoirs to a great extent, and provide reference for development of similar difficult-to-produce reserves.