What is a primary disadvantage of bucket rigs?

Bucket rigs are primarily designed for freestanding or unconsolidated formations, making them less effective when working with consolidated shale. In consolidated formations, the rock is tightly bound, which makes it difficult for bucket rigs to efficiently excavate and remove material. These rigs rely on the mechanical action of the bucket to scoop up soil or rock, and this action is significantly hindered in harder, more solid formations where more robust equipment might be necessary.

While factors such as speed, workforce requirements, and operational costs are also important considerations in drilling operations, the distinguishing characteristic that limits the effectiveness of bucket rigs is their lack of suitability for consolidated materials. Thus, their operational efficiency is greatly compromised in such conditions, emphasizing the point of their primary disadvantage.