Important Considerations in Geosteering

Important Considerations in Geosteering

1)      Avoid over-reacting to short-term changes in apparent dip. Apparent dip changes are often simply the result of thickness difference relative to the type log.

2)      Know the nuances of the target interval in areas with significant HZ control.

3)      Be as accurate as possible with correlations when first drilling through the target interval because that is what one will be correlating against as the bit moves through it.

4)      Do not neglect data from parallel offset horizontal wells. There may be differences but theses other wells are generally very good guides

5)      Be wary of interpreting faults without drilling more section. Sometimes a re-interpretation of previous data is required.

6)      Limestone % interpreted by mudloggers is good confirmation of a lime stringer or undesirable lime zone as is ROP.

7)      Anticipate and prepare for expected dip changes as much as is possible.

8)      Geosteerers who watch the well on real time WITS systems are better prepared to react quickly to changes in dip.

9)      Sometimes it is better to utilize a constructed offset horizontal TVD log as a type log to land the curve rather than a vertical well that is either too far away or has been found to have irregularities in the section. This is not always the case as sometimes offset HZ wells are and need to be landed at high dips which can also skew the section. An acceptable vertical well log is generally better if available.
10)   Generally speaking, the correlation that favors a more constant dip is more likely to be correct.

I may update these in the future as I think of more.