Abstract: A mandrel housing for permanently deploying a seismic sensor or sensor apparatus down a well is disclosed. The mandrel is formed integral with or attached to a pipe and is incorporatable into the production piping string. The outer diameter of the mandrel is designed to be slightly smaller than the inside diameter of the well casing which allows the mandrel to naturally come into contact with the well casing at points of deviation, non-linearity, or non-verticality in the casing. This mechanical coupling of the mandrel to the well casing, and hence the earth formation, improves the resolution and type of seismic signals to be detected by the sensor apparatus. The sensor apparatus fits into a groove on the mandrel and is preferably clamped or welded into place or placed within a tunnel formed in the mandrel. The mandrel further preferably contains channels on its side to allow materials within the annulus to flow around the mandrel even when the mandrel is in contact with the casing.