Magnetic Ranging Method for Horizontal Section Spacing Control of Cluster Wells

Abstract

Summary Interwell fracture interactions are becoming an increasing problem with the large-scale exploitation of shale gas. High precision ranging technology is required for controlling the horizontal section spacing in cluster horizontal well drilling projects. The existing magnetic ranging technology has achieved remarkable application effects in the drilling engineering of twin horizontal wells, connected wells, and relief wells. But the maximum detection range cannot meet the needs of cluster horizontal well drilling engineering. A magnetic orientation sub connected to the nonmagnetic drill collar was designed to mark the position of the wellbore being drilled. Compared with the conventional magnetic sub connected to the drill bit, the magnetic orientation sub has a higher magnetic moment, is closer to the inclinometer, and has less effect on the build-up ability of the drilling tool. Although the effect of the magnetic orientation sub on the azimuth measurement is small when the azimuth angle is equal to 90° or 270°, the effect cannot be neglected in most cases. Therefore, we develop a computational model of the azimuth that considers the influence of the magnetic orientation sub. A new calculation model of distance and direction from the wellbore being drilled to the existing wellbore is developed to realize the ranging every 30 m or so. And the simulation experiment shows that the calculation accuracy of the distance and direction can meet the field needs of cluster horizontal well drilling engineering.