Discover a Career - What the future holds for positions in underbalanced drilling.
Despite the drilling industry’s shift toward managed pressure drilling (MPD) over the past half-decade, underbalanced drilling (UBD) continues to be a desirable option for many operations today, especially when drilling into pressure-depleted formations and/or attempting to reduce skin damage for better productivity. Because of this sustained demand, largely by operators willing to pay top dollar for skilled UBD personnel, a fundamental knowledge of the technique can benefit young petroleum engineers looking to excel in their field.
The philosophy of UBD is diametrically opposed to traditional/conventional drilling methods and MPD. Conventional drilling uses an equivalent mudweight (EMW) that results in a bottomhole pressure (BHP) greater than that of the pore pressure exposed to the open hole to prevent formation fluids (oil, gas, or water) from entering the wellbore. MPD uses equivalent circulating density—a combination of hydrostatic pressure, circulating friction pressure, and applied surface pressure—to create a BHP equal to or greater than formation pore pressure.