Gyro Single Shots
The Gyro Single Shot is used for orienting purposes only. While drilling, Gyro Single Shot surveys shall be taken instead of magnetic surveys or MWD whenever magnetic interference may be present. Gyro Single Shot are also used for ‘tying-in’ MWD surveys.
Interference is likely to happen within 50 ft of steel fish or casing strings in adjacent wells and within 50 ft of the casing shoe or casing window in the same well.
Check Surveys
Magnetic check surveys should be taken to determine from which depth subsequent magnetic surveys shall . . .