A油田致密油储层驱替介质优选

Optimization of Displacement Media for Tight Oil Reservoir in Oilfield A

致密油藏目前主要利用水平井压裂进行开发,初期产量较高,地层能量衰减后产量迅速递减,未能实现致密油的长期经济有效动用。针对此问题涌现出了同井缝间注采、拉链式分布驱替等新的技术手段,为了验证此类技术在A油田应用的可行性,在A油田致密油A区块选取天然岩心,进行表面活性剂驱、二氧化碳驱、天然气驱及氮气驱室内岩心驱替实验,明确了不同介质的增油潜力与驱替难度。根据实验结果分析,水驱后使用上述介质能进一步提高驱油效率,提高幅度为9.79%~31.06%,其中二氧化碳驱增幅最大。数据表明,以目前的注入能力及水平井裂缝分布情况来看,要实现致密油驱替,动用储层内的剩余油,只有通过注入气态介质才具备实施的可行性,液压介质受过高的驱替压差制约,暂不具备实施的可行性。

At present,tight oil reservoirs are mainly developed by horizontal well fracturing.The initial production is high,and the production declines rapidly after the formation energy decay,which fails to realize the long-term economic and effective use of tight oil.To solve this problem,new technical means such as injection-production between fractures in the same well and zipper distributed displacement have emerged.In order to verify the feasibility of the application of such technologies in oilfield A,natural cores were selected in tight oil block A of oilfield A,and core displacement experiments were carried out in surfactant flooding,carbon dioxide flooding,natural gas flooding and nitrogen flooding to determine the oil increase potential and displacement difficulty of different media.According to the analysis of the experimental results,the oil displacement efficiency can be further improved by using the above medium after water flooding,with the increase range of 9.79%~31.06%,and the increase rate of carbon dioxide is the largest.The data show that,based on the current injection capacity and fracture distribution of horizontal Wells,the implementation of tight oil displacement and the use of remaining oil in the reservoir is feasible only by injecting gas media,and the implementation of hydraulic media is not feasible due to the high displacement differential pressure.