高分辨率阵列感应测井动态响应的计算分析

Calculation and Analysis of Dynamic Responses for High Definition Induction Log

钻井泥浆滤液对地层的侵入使地层相关参量的侵入剖面随侵入时间变化,高分辨率阵列感应测井(HDIL)的响应也随测井时间的不同而异。建立在两相渗流理论基础上的动态侵入理论可以求解侵入过程地层电阻率的剖面变化,进而求出HDIL的视电阻率随侵入时间的变化。HDIL动态响应可以同时给出测井空间和时间信息。对人工储层模型的理论计算分析表明,对于不同储层和不同测井时间,6个HDIL视电阻率的大小排列有一定规律。当使用淡水泥浆钻井时,油层的视电阻率按深探测到浅探测有序排列,水层反之。对于油水同层,在侵入前沿出现的低电阻率环带对测井结果产生严重影响,在侵入初期,HDIL的各个视电阻率大小出现乱序。这些规律有助于正确了解HDIL新型测井仪器的侵入响应特性,为正确评价储层性质、确定地层真电阻率和原始含烃饱和度提供了帮助。

Since the process of drilling mud filtrate invading formation changes with time, the correlative invasion profile parameters also change with invasion time. So, the responses of high definition induction log （HDIL） change with time too. The dynamic invasion formula based on two-phase percolation theory can calculate formation resistivity profile variations in invasion process, and then, obtained are the variations of apparent resistivity with invasion time of HDIL. Dynamic HDIL responses can provide information both in coordinate and time simultaneously. The coordinate information provides radial responses for six radial depths, and the time information gives the HDIL responses at various time stages. The formation calculation and analysis model shows that the six apparent resistivity responses of HDIL tool arrange with some rules for different invasion time and various reservoirs. When fresh water mud filtrate is used, the apparent resistivity arranges from deeper detective responses to shallower detective responses for oil reservoir, and vice versa for water zone. Whereas the HDIL responses become disorder for both bearing oil and water reservoir because a low resistivity annular in the front of invasion zone effects on the logging data seriously. The present results not only provide the physical understand of invasion characters of new HDIL tool for log analysts, but also are helpful for reservoirs evaluation, determination of the true formation resistivity and initial hydrocarbon saturation.