A Feasible Method for the Trajectory Measurement of Radial Jet Drilling Laterals

Abstract

Summary Radial jet drilling (RJD) is an unconventional drilling technology that uses high-pressure liquid jet to drill multiple radial laterals. It is a cost-effective alternative for bypassing damage zones near the wellbore, restimulating the production of old wells, and developing unconventional reservoirs. However, because of the structure of the deflector and the diameter of the radial laterals, traditional well-trajectory measuring tools cannot be applied in RJD wells, which hinders the conduct of some significant operations. The unknown trajectory is a crucial limitation to further development and field application of RJD technology. In this paper, along with an introduction to RJD technology, a measuring system and a mini-tool are proposed for attitude measurement and motion-state recognition. With an extra tripping stage, the tool is tripped down to the bottom of the RJD laterals after the jet drilling is completed, and then tripped out at a constant speed. The measured data stored in memory media could be downloaded after the measurement. On the basis of navigation theory, a reckoning method was proposed to obtain the trajectory parameters by using the recorded data of the tool and the operational data of the coiled tubing (CT). After that, an experimental study was carried out to test the performance of the measuring tool and the reckoning method. As results of the experiments demonstrate, the average errors of the measured length, inclination, and azimuth are 3.94, 2.62, and 4.54%, respectively.