利用动态侵入测井响应识别低电阻油气层

Identifying low-resistivity reservoirs by means of dynamic invasion logging data

高矿化度钻井液侵入是造成油气层低电阻的主要因素之一,泥浆浸泡时间愈长,测井结果对地层真值的偏离愈甚,测井解释难度越大.钻井泥浆侵入地层的动态测井模型是基于多相渗流理论、岩电关系和测井理论建立起来的,它为识别由于高矿化度泥浆侵入形成的低电阻油气层提供了一个有效手段.介绍了根据按时间记录的电阻率测井响应,利用试错法对测井响应进行模拟计算,从而反推得到原状地层的真电阻率的方法.该方法为低电阻油气层的识别提供了可靠的依据.

The invasion of high-salinity mud is one of the reasons why the formation resistivity is low. The longer the time when the reservoir soaks in the mud, the more the logging responses deviate from the true formation resistivity, and the more difficult the logging interpretation becomes. The dynamic logging model for describing drilling fluid invading formation is established based on multi-phase seepage flow theory, the formula of the electric property of rock and logging theory, which provides a effective method for identifying the low-resistivity oil/gas reservoirs caused by the invasion of high-salinity mud. The trial-and-error method is used to simulate the resistivity record from logging data, and then the true formation resistivity is obtained by inversion.