With the development of the Bohai oilfield, the proportion of "low production, marginal and viscous" oilfield increases, and the implementation of infill adjustment wells becomes more difficult. Meanwhile, the complex reservoir is easy to lead to landing failure, low drilling rate and downhole accidents. Due to its own limitations, conventional edge detection logging technology can not meet the development and adjustment needs of complex oil and gas reservoirs. It is necessary to introduce the new detection while drilling technology to improve the depth, accuracy and efficiency of edge detection. Along the long⁃distance drilling technology, Schlumberger's high⁃definition multilateral exploration technology and ultra⁃deep multilateral exploration technology are combined in an innovative way. The detection distance is greatly increased to 76.2 meters, with higher resolution, more accurate landing guidance and more precise reservoir description. Through the actual data acquisition, analysis and comprehensive comparison of the adjustment wells C13H1 and P6H1 in the Bohai oilfield, the technology successfully guided the landing, and clearly explored the reservoir boundary more than 20 meters ahead, which greatly improved the reservoir drilling rate，development and production effect.