APPLICATION OF A NOVEL MAGNETIC GUIDANCE DRILLING TECHNOLOGY IN COALBED METHANE PRODUCTION BASED ON ENERGY SAVING AND ENVIRONMENTAL PROTECTION CONCEPT

摘要

Coalbed methane is a kind of efficient and clean energy.Magnetic guidance drilling technology is use of magnetic guidance instrument measuring the distance between the signal source and the location of the instrument,and it is used to control the well trajectory to connect or parallel the target layer.And it is an effective supplement of the existing steering drilling technology.And magnetic guidance technology is the key of drilling coalbed methane well successfully.It plays an important role in drilling of parallel horizontal wells and connected wells.In this paper,the components,structures and functions of the magnet ranging system are described,and then the design is discussed on underground system of target-side,strong magnetism sub on source and other key down-hole structures.By analyzing the principle of the algorithm of RMRS and characteristics of the magnetic field strength based on Hilbert transform method,a high precision guide positioning method suitable for dynamic alternating magnetic field is proposed.Surface simulation tests show the rationality of the RMRS and correctness of the positioning algorithm.With the shortening of distance between source side and the target decreases,higher accuracy and smaller error can be obtained to enable accurate ranging within 40 m.At present,the magnetic guidance drilling technology is mainly applied to drill horizontal wells in pairs for the super heavy recovery,CBM horizontal connected wells,underground soluble minerals,relief well and so on.Research results may provide solid technical supports for the development of domestic magnetic orientation instruments and the technical improvement of magnetic guided drilling techniques in China.