Abstract: The relief well, Wen23-6J, for the Well Wen23-6X is the first relief well drilled with the aid of SDI's magnetic range correction technology, and will greatly help in building a working gas storage of 3.9×10⁸ m³ (active storage of 7.93×10⁸ m³). The Well Wen23-6X is an accidental well drilled in 2005, with 2,300 m of fish left in it. Long time of contact of borehole wall with drilling fluid makes it difficult to (even with SDI's advanced technology) detect the well path with no fish in it when drilled to 2,588m. The newly drilled hole only met with the old hole at five depths during drilling. 73 m3 of cement slurry was injected in 8 times into the hole to the meeting points. To ensure an effective sealing of the hole, a fixed direction–fixed tool face orientation perforation technology was applied the first time after the cementing of the relief well. Ultra-fine cement slurries were squeezed into #34 and #29 sandstones. Negative pressure (37.84 MPa) testing shows that the plugging of the well is successful and gas storage can be built around the relief well.