Bottom Hole Assembly
Bottom Hole Assembly, commonly known as BHA refers to a set of tools between the drill bit and drill pipe. One of the main objectives of BHA is to have enough weight to transfer to the bit to enhance the bit's ability to cut hard rocks. A conventional BHA for drilling vertical wells is designed as a tapered string with a larger diameter and heavier drill collars above the bit. A well-designed BHA produces a smooth hole, minimizes vibration, maintains the intended profile of the well, and improves bit performance.