1. Instrument calibration: must be strictly calibrated for the FOG before use to ensure the accuracy of measurement. 2. Environment assessment: understand the temperature, pressure, humidity and other environment conditions of the oil well to ensure FOG can work normally under these conditions.

1.Measurement accuracy: according to the accuracy requirements of the oil well survey to choose.If the measurement accuracy is required, FOG with high resolution and low error should be selected. 2.Operating temperature range: the temperature conditions in the oil well may be harsh, it’s need to choose a FOG that can work stably in the range of high temperature or large temperature changes.