用方位密度成像测井资料计算水平井钻遇地层倾角的方法

Formation Dip Calculation by Azimuthal Density Image Data

Schlumberger公司的随钻方位密度测井(ADN)可以提供井周16个方位的密度成像资料,为过井眼的地质界面产状的计算提供了方便。对于垂直井或大斜井,当井眼穿过一个有明显电测响应变化的地质界面时,利用井壁成像资料可以方便地描述地质界面的产状;对于水平井,由于井眼轨迹基本与地层平行,井眼轨迹常常只能穿越地层界面。传统的对界面产状的描述方法已不再适用。提出了一种利用方位密度成像测井计算水平井井旁地层产状的方法。希望随着测井新技术的出现不断完善新的解释方法,以提高随钻方位密度测井的使用范围和精度。

Schlumberger LWD Azimuthal Density Neutron （AND）tool can measure the wellbore formation density in 16 sectors and provide the well bore formation density image. This azimuthal density measurement may be used to calculate the formation dip. For the vertical well or slant well,when the well bore penetrates through the formation boundary with different logging responses, the formation image may be used easily to caculate the formaton dip; however, for the horizontal well, the well trajetory may be parall to the formation layers and the well bore might just touch instead of penetrating the formation layers. Then the traditional method of dip calculation may not be available in such case any more. Here the new method of dip caculation by using azimuthal density image data is developed and illustrated in this article. It is open for comments and discussion with experts in all fields. With the continuous new logging technology introduction and improvement of logging interpretation analysis, hopefully it would help to improve the accuracy and scope of azimuthal density application.