Dual-gradient drilling (DGD) provides the same bottomhole pressure as a single mud weight from the surface to total depth (TD) with a combination of two fluid gradients: slightly heavier mud from the mudline to TD and seawater from the mudline back up to the rig floor. With DGD, margins between fracture gradient and pore pressure are significantly greater while drilling the well. Lower-cost wells can be drilled by use of DGD more safely and with more completion flexibility than with single-gradient systems.