Systems And Methods For Obtaining Apparent Formation Dip Using Measurements Of Different Effective Penetration Length

摘要

Systems and methods for identifying formation boundaries without necessarily obtaining an azimuthal borehole image are provided. A downhole tool may be placed in a wellbore in a geological formation that has a formation boundary. First and second measurements may be obtained at a number of depths of the wellbore. The first measurement may have a first effective penetration length into the geological formation and the second measurement may have a second effective penetration length into the geological formation different from the first effective penetration length. Thus, the first measurement may detect the formation boundary at a first depth and the second measurement may detect the formation boundary at a second depth. Using a difference between the first depth and the second depth, an apparent relative angle between the wellbore and the formation boundary or an apparent formation dip, or both, may be obtained.

主权项

1. A method comprising:
placing a downhole tool in a wellbore in a geological formation that has a formation boundary; obtaining a first measurement and a second measurement of the geological formation using the downhole tool at a plurality of depths of the wellbore, wherein the first measurement has a first effective penetration length into the geological formation and the second measurement has a second effective penetration length into the geological formation different from the first effective penetration length, such that the first measurement detects the formation boundary at a first depth and the second measurement detects the formation boundary at a second depth; and determining an apparent relative angle between the wellbore and the formation boundary or an apparent formation dip, or both, using a difference between the first depth and the second depth.