西区延_9储层注水过程中敏感性伤害因素分析

陕北延长油田西区采油厂的作业区块存在注水压力升高、渗透率降低和采收率降低等问题。分析该区块延安组的储层物性特征、粘土矿物含量、注入水和地层水组成性质,并进行了储层敏感性流动实验。实验结果表明:该区块储层具有弱速敏和强水敏性,注入水的矿化度明显低于地层水的矿化度,与地层配伍性较差。较低的注水矿化度是造成储层强水敏的主要因素,而强水敏又会导致注水压力迅速升高和渗透率大幅降低。因此,建议在注入淡水时加入粘土稳定剂或者对地层采出水处理后回注。

Damage reasons analysis of sensitivity on waterflood of reservoir of xiqu Yan 9 formation

There are some problems like increased injected water pressure,decreased permeability,decreased recovery in Xiqu oilfield which is in the Yanchang oilfield in Shanbei.Analyze the physical properties characteristics,clay mineral content,composition and properties of injection water and formation water of this formation,and apply the reservoir sensitivity flowing experiment.The result is this reservoir is belonged to weak velocity sensitivity and strong water sensitivity reservoir.Moreover,the injected water salinity of Xiqu is obviously lower than the formation salinity,and the compatibility with formation is much worse.The low salinity of injection water is the main reason that makes strong water sensitivity of this formation,and the strong water sensitivity make the injection pressure ascend faster and the permeability of formation fluid decrease obviously.So,this article supposes to add to clay stabilizers when injecting freshwater or reinject formation produced water after treating.