DOG drilling on gauge sub has been specifically designed to deliver at-the-bit reaming performance. Its short body design and durable cutting structure enable placement between the bit and the mud motor in directional applications. Shortening the distance from the bit to the first point of stabilization improves BHA and drilling performance. The DOG sub prolongs the effectiveness of the bit and provides an early indication when the drill bit begins to lose its gauge.
Synthetic diamond-enhanced inserts (DEIs) provide a durable cutting structure, designed for continuous reaming and capable of maintaining a full-gauge hole in soft to medium-hard formations.
Each insert is brazed into the body, and consequently, there are no moving parts to wear or fail. In directional wells where doglegs would necessitate a reaming run through the build section, the DOG sub may provide the adequate reaming and contact behind the bit, wiping out the ledges as drilling progresses. A smoother build section can reduce hole drag and facilitate drilling operations.