定边特低渗油田储层伤害研究

Study on Reservoir Damage in Dingbian Special Low Permeability Oilfield

定边低渗油田是低孔隙低渗透油田,面临注水压力高,其他各种作业对储层伤害大等问题,严重影响油井产量。通过X衍射,扫描电镜等分析储层孔隙结构和粘土矿物含量,敏感性矿物含量高,并通过岩心伤害实验评价得出了该区块伤害程度,阐明伤害机理。实验结果表明：储层速敏伤害在中等偏弱至强,盐敏临界矿化度在40 000-2 000 mg/L。酸敏伤害在中等偏强至强酸敏,以及水锁伤害在18%-52%之间等。对此,提出了针对储层保护的建议,从而减少储层伤害,提高油田采收率。

Dianbian oilfield has the characteristic of low porosity,poor permeability and high content of sensitivity mineral.Dainbian oilfield faces the problem of high pressure of the injected water and damaging oil reservoir greatly.In this paper,pore texture and clay mineral content in oil reservoir were analyzed by X-ray diffraction and scanning electron microscope.Meanwhile,damage degree of the block was evaluated by the core damage experiment,and damage mechanism was discussed.The results show that damage from the velocity sensitivity is in the range of medium（-） to strong,critical salinity is in the range of 40 000-2 000 mg/L,damage from acid susceptivity is in the range of medium（＋） to strong,and water-lock damage is 18%-52%.At last,reasonable advices to protect oil reservoir were put forward to reduce damage of reservoir and improve oil recovery.