To figure out if the well is considered an ERW, calculate the ratio of horizontal departure to vertical depth. If the depth ratio is greater than 2, the well is considered an Extended Reach Well (ERW). An ERW can be relatively long and deep, short and shallow, or something in between. The benefit of Extended Reach Drilling is the increase in efficiency by exposing the open hole to long sections of the reservoir rock, or by crossing through multiple reservoirs in one long well-bore. It is expensive and risky but it is sometimes the best option available. With advances in technology, these wells are getting longer and longer as we get better at overcoming the challenges of managing down-hole pressure, managing and controlling the mechanical loads on the drill string, and hole cleaning.