Abstract:

The intrinsic difference between horizontal well and vertical well is that media don′t show radial symmetry around the wellbore.Therefore，such situations as aeolotropism，thin bed and inclined layer will become more difficulty in log interpretation of horizontal well.Stratum data acquired from LWD（loggingwhile drilling），because of the two characteristics of immediacy and uthenticity，have favorabe dominance in log evaluation of horizontal well，and can be used to effectively distinguish stratum，oil and gas reservoir（gas reservoir especially）.The text describes some oftenused methods in layer interfaces recognition，reservoir evaluation and fluid contact recongnition，which can be used in log evaluation of horizontal well.In addition，taking a carbonate horizontal well drilling in Sichuan oil province as example，application of LWD data in this well is evaluated，to take a step further，some problems how LWD data will be better used in log evaluation of horizontal well are proposed.

Key words: horizontal well, logging while drilling, reservoir evaluation, layer interfaces, gas water interface