吐哈盆地台北凹陷低电阻率环带油层阵列感应测井识别方法

Identification Method of Low Resistivity Annulus Oil Reservoirs with Array Induction Logs in Taibei Sag,Tuha Basin

吐哈盆地台北凹陷西部油田具有中高地层水矿化度(50 000～100 000mg/L)、低原油黏度(小于10MPa.s)、较高束缚水饱和度(大于40%)等特点,存在大量具有低电阻率环带的油层。该类油层电阻率增大率仅1.5左右,侧向电阻率测井在识别该类油层时具有一定的局限性。通过分析低电阻率环带的形成条件,以及低电阻率环带油层阵列感应测井响应特征,依据阵列感应测井提供的不同探测深度的6条电阻率曲线,并结合该地区低电阻率环带分布特点,建立了低电阻率环带油层识别方法。研究成果丰富了台北凹陷西部低电阻率油层的评价手段。

The reservoir is characterized by middle-high formation water salinity （50 000 100 000 mg/L）, lower oil viscosity（less than 10 MPa · s）, higher irreducible water saturation （more than 40%） in Western oilfield of the Taibei sag, Tuha basin. So, there are plentiful oil reservoirs with low resistivity annulus in this area. The resistivity increase index is about 1.5 in this oil reservoir, it is restrictive to identify such oil reservoir by laterologs. Analyzed are the ge- netic conditions of low resistivity annulus, the response characteristics of array induction logging in oil reservoir with low resistivity annulus. According to the six resistivity curves of different probing depths provided by array induction logging, and combing with distribution characteristic of low resistivity annulus in this area, proposed are identification methods for oil reservoir with low resistivity annulus. The study enriches evaluation method for low resistivity oil reservoir in the western of Taibei sag, Tuha oilfield.