Method for Selecting Bed Boundaries and Log Squaring Using Electromagnetic Measurements

摘要

Techniques for log squaring using both directional and non-directional electromagnetic measurements are disclosed. The techniques described herein can be used for determining bed boundary locations and assigning resistivity values to each layer in a layered earth model, regardless of well deviation. Potential bed boundary locations can be derived from both directional and non-directional electromagnetic measurement data. The bed boundary locations from the directional and non-directional measurements can then be consolidated using a weighted averaging scheme, where weight can be dependent based on apparent formation dip. By combining the results from both directional and non-directional measurements, the log squaring techniques described herein can be used in most wells regardless of the well angle (the angle can be arbitrary). Once bed boundaries are selected, formation properties, such as horizontal resistivity (Rh) and vertical resistivity (Rv) can be assigned to the model layers.

主权项

1. A method comprising:
using an electromagnetic logging tool to acquire directional and non-directional resistivity measurements in a wellbore formed through a subsurface formation; applying filtering to the directional and non-directional resistivity measurements; identify peaks in the directional and non-directional resistivity measurement curves as potential bed boundary locations; constructing a bed boundary curve by combining the identified peaks and their corresponding magnitudes using a weighting function based at least partially upon the apparent formation dip; consolidating the peaks on the bed boundary curve to define individual bed boundaries; and assigning resistivity values to each layer, as defined by the individual bed boundaries.