Study on a Ranging System Based on Dual Solenoid Assemblies, for Determining the Relative Position of Two Adjacent Wells

Abstract

The measurement of the relative position of two adjacent wells is one of the key technologies in the directional drilling of twin parallel horizontal wells, and the downhole intersection of two adjacent wells. A new electromagnetic ranging system and a guidance method are introduced for determining the relative position of two adjacent wells. The system mainly consists of two solenoid assemblies, improved surveying instrument for measurement while drilling (MWD), and a computational procedure for guidance. Also, the distribution of the magnetic field of each energized solenoid assembly is discussed, by regarding the solenoid assembly as two independent oscillating magnetic dipoles. Through a case study, it is shown that the accuracy of computation of the ranging, and method of guidance of the system can meet the requirements of implementation in the field. It is shown that the solenoid assemblies should be placed near the target point for the two intersecting wells, or under the improved MWD survey instrument for the twin parallel horizontal wells. During the measurement while drilling, the solenoid assemblies can be motionless, and avoid absorbing too many iron filings. Therefore, the system has a higher precision and less operational time, during the measurement while drilling.