Abstract: A means of investigating the quality and/or nature of perforations in a downhole environment is disclosed. A ‘pecking’ finger and depth measuring probe that can be axially and radially displaced enables the perforation to be located and its depth determined, through sequentially pecking around the wall lining in patterns such as radial, axial, and spiral sequences. By swinging a pecking finger that supports a depth measuring probe or cable with a bullet or conically shaped tip and measuring the displacement of the finger, the edge and centre of the hole can be determined with the largest displacement being when the tip is fully in the hole. When this position has been determined, the depth measuring cable is deployed and the depth of the perforation can be established by both an increase in the force required to push the cable and by the displacement of the pecking finger as it is pushed back by the reaction forces on the cable.