Application of horizontal gyroscope in trona directional intersecting wells

Abstract:

Magnetic guidance is a mature intersecting method applied in solution mining of trona via directional intersecting wells. However， when pyrite susceptible to magnetization exists in strata， the pyrite will be magnetized and turn into a strong magnetic body during the well intersection stage. On one hand， prolonged exposure of non-magnetic drill strings to strong magnetic environments degrades the magnetic shielding performance， causing azimuth errors in MWD measurement. On the other hand， if the target cannot be hit at the first attempt during magnetic target hitting in the horizontal section， magnetic anomalies will completely invalidate the magnetic azimuth measurement of MWD， and no azimuth data will be available to guide sidetracking for the second target hitting. The horizontal gyroscope can be adopted to measure non-magnetic drill strings in the deflection section and calibrate the MWD azimuth data. It determines the azimuth independent of the geomagnetic field in the horizontal section， providing data support for subsequent drilling and sidetracking for secondary target hitting. In several domestic trona intersecting wells， horizontal gyroscope logging was adopted. Well interconnection was successfully achieved for multiple intersecting wells with a target width of approximately 152 mm under strong magnetic interference. The results verify the feasibility and reliability of horizontal gyroscopes under such working conditions.