What are the two categories of drilling methods?

The correct answer identifies rotary drilling and percussion drilling as the two fundamental categories of drilling methods. These methods are distinguished by the techniques utilized to penetrate the earth.

Rotary drilling involves the use of a rotating drill bit that grinds through rock and sediment. This method is common in many applications, including oil and gas drilling, as well as water well construction, due to its efficiency in penetrating hard formations. The continuous rotation of the bit allows for a continuous flow of cuttings out of the borehole, enabling deeper penetration and better control over the drilling process.

Percussion drilling, on the other hand, operates by repeatedly striking the drill bit into the ground, which is often useful in softer rock or unconsolidated materials. This method uses a hammering action to break up the material, making it effective for specific applications where rotary drilling may be less efficient.

The other choices presented represent different categorizations or aspects of drilling but do not delineate the primary methods of drilling. For instance, while surface and underground drilling address the location of the drilling operations, they do not focus on the operational methodologies. Manual and automated drilling refers to the level of human intervention involved but does not classify the drilling methods themselves. Vertical and horizontal drilling pertain to the orientation