冀中坳陷高凝油录井识别方法探讨

Discussion on the method of mud logging identification for high-pour point oil in Jizhong Depression

冀中坳陷存在一种特殊的中质油,其含蜡量一般为21%~35%,凝固点为35~67℃,析蜡温度为60~74℃,属于高凝油。此类原油在低于其凝固点时以固态形式存在,当井筒温度低于析蜡温度时原油流动性变差,常规的试采工艺难以有效地将原油采出。在以往的解释评价过程中,因未能识别高凝油,导致解释与试油结果矛盾突出。利用岩石热解气相色谱分析技术对高凝油进行有效识别,同时建立相应的识别图板,可为提高此类油层的解释符合率及试油工艺优选提供依据,有效解决了随钻快速识别高凝油的难题,提高了勘探成功率。

There is a special intermediate oil in Jizhong Depression,its wax content is generally 21%~35%,the freezing point is 35~67℃,and the wax precipitation temperature is 60~74℃,which is a high-pour point oil.This type of crude oil,whose fluidity weakens when the wellbore temperature is lower than wax precipitation temperature,exists in a solid form below its freezing point,making it difficult to effectively produce crude oil with conventional well test and production techniques.In previous interpretation and evaluation,the high-pour point oil was not identified,resulting in salient contradictions between interpretation and oil test results.Rock pyrolysis gas chromatography analysis was used to effectively identify high-pour point oil,meanwhile,a corresponding identification chart was established,providing a basis for improving interpretation coincidence rate of this type of oil layer and the optimization of oil test techniques.It effectively solved problems in rapid identification of high-pour point while drilling,and increased exploration success ratio.