Abstract: Capping and reconstructing old wells is the basic core work in gas storage construction. The main feature of multi-borehole old wells is that there are multiple boreholes in the same wellbore, and the capping process is very complicated, which urgently needs a fast and reliable well capping method. By systematically analyzing the technical difficulties faced by capping multi-borehole old wells, including adjacent borehole interference, unknown borehole status, inaccurate trajectory prediction, and deviation in sounding, a solution integrating rescue well anti-collision, ranging, trajectory control, and logging technology, which is based on domestic passive magnetic steering tools, was proposed. On-site tests were carried out in two old wells with different well conditions and multiple boreholes in the offshore gas storage in Jidong Oilfield, and the re-entry well capping target was successfully completed. This technical solution provides a complete solution for capping multiple boreholes in gas storage, and has good promotion and application value.