CT扫描技术在水敏伤害评价中的应用

Application of CT Scanning Technology in Water- sensitivity Damage Evaluation

常规储层敏感性评价方法无法准确反映发生伤害的具体区域,同时也缺少对敏感性伤害程度的定量评价。以2块采自老君庙油田同一层位的岩心为例,利用CT扫描技术开展储层水敏伤害评价实验研究,分别开展水驱和＂设计＂水驱实验,同时基于CT扫描原理建立相应的水敏伤害评价方法。水驱实验中注入压力和CT值的变化表明,实验用水与岩心接触时存在很强的水敏伤害。在＂设计＂水驱实验中,分析CT扫描孔隙度分布可确定水敏伤害主要发生在注入端附近,并可估算出平均孔隙度降低10%～15%;同时通过对比水敏伤害切片孔隙度图像前后变化,可准确反映出岩心中发生水敏伤害的具体区域。

Conventional reservoir sensitivity evaluations are unable to accurately identify specific damage area and quantitatively evaluate the damage extent. Two core samples which collected from a same layer and CT scanning are used to evaluate reservoir water- sensitivity damage. Waterflooding and'design'waterflooding experiments are carried out,and a water- sensitivity damage evaluation is established based on CT scanning principles. The test injection pressures and CT values indicate that serious water- sensitivity damage is generated in case of the contact between experiment water and core samples. Water- sensitivity damage mainly generates in the vicinity of the injection side,which can be determined by the CT porosity distribution in the'design'waterflooding experiments,and the average porosity is estimated to be decreased by 10%- 15%. In addition,the specific water- sensitivity areacan be accurately identified through comparing the section porosity images before and after water- sensitivity damage experiment.