Application of electromagnetic detection and location system in the design of relief well

Due to uncertainties of wellbore track, appropriate detection and location tools must be used to connect the relief well and the accident well. Thus, the research of electromagnetic detection and location system is important to the design and operation of relief wells. This paper studies the basic principle of electromagnetic detection and location system (EDLS) and analyzes the calculation method of casing collection current in accident wells using the EDLS and its distribution characteristics; the paper also investigates the calculation methods of relative distance and relative direction between the relief well and the accident well; in combination with the practical applications of the EDLS, the effects of casing parameters, cutting angle, hole drift angle, and formation and other parameters in the accident well on the measurement effects and applications of the EDLS are analyzed; building on the analysis of the EDLS, the distance measurement and connection in the design of a super deepwater relief well in the South China Sea is finished. This paper can provide a theoretical basis for the development of EDLS for relief wells and offer a reference for the application of EDLS in the design and operations of relief wells.