DOM

Weatherford’s Depth Orientation Marker (DOM) is a device used to provide long-term, downhole reference points. This is done by focusing a magnetic field inside the casing that affects the casing collar locator (CCL) tool as it passes through the string. The magnetic field generated by the DOM distorts the CCL field, creating an induction current in the tool and a “blip” on the log that is at least 50% stronger than the normal casing collar “blip.” On flush-joint casings, the DOM often appears as the only clear “blip” on the CCL log.