注水压降试井结合吸水剖面测井精准识别大孔道

Accurate Identification of Large Channels Through Water Injection Pressure Drop Well Test and Water Absorption Profile Logging

为解决多年注水开发油田地层非均质性严重,大孔道占比增加,注水形成无效或低效循环等问题,进行了大孔道的识别方法研究。利用注水压降试井曲线近似90°弯曲和双对数曲线大开口、低径向流线的“异常”特征,进行大孔道预警。然后结合吸水剖面测井显示的窄幅吸水,佐证大孔道的存在。再以吸水剖面测井给出的实际吸水厚度重新计算渗透率,若渗流能力与相邻区域相比呈强烈突变关系,可精准识别大孔道。该方法将两种常用的动态监测手段有效结合,互为佐证,可靠性增强,可定量描述大孔道,为后续调剖调驱等措施提供依据。

After years of water injection development,the problem of formation heterogeneity becomes serious and the proportion of large channels rises,which leads to invalid or inefficient circulation of water injection.To solve these problems,many methods are studied to identify large channels.First,the“abnormal”characteristics,which includes water injection pressure drop well test curve with approximate 90°bending and double log curve with large opening and low radial flow line,are used for large channel warning.Next,the existence of large channel can be proved by combining the narrow range of water absorption indicated by the water absorption profile logging.Then,the actual water absorption thickness given by the water absorption profile logging is used to recalculate the permeability.If the seepage capacity presents a strong mutation relation with the adjacent area,the large channel can be accurately identified.This method combines two common dynamic monitoring methods effectively,which can be used as evidence for each other.Thus,this new method enhances the reliability and puts forward a quantitative description of large channels,providing a basis for subsequent profile control,flooding and other measures.