Geomechanics and hydraulics modeling are commonly used to optimize drilling performance and to reduce non-productive time (NPT). The geomechanics model indicates safe mud weight parameters, optimum casing points, and wellbore stability analyses. The hydraulics model simulates the wellbore and drilling fluid parameters to optimize the flow rate and rate of penetration (ROP) within equivalent circulating density (ECD) constraints. Real-time drilling data are used to update the models: the pore-pressure/shear-failure gradient and fracture gradient boundaries for geomechanics; and ECD, circulating system pressure drops, and annular cuttings load parameters for hydraulics. Each real-time model strives to ensure that operations are optimal, safe, and cost effective, as well as to provide updated models for future planning purposes.
This paper focuses on collaboration between geomechanics and hydraulics analysts in the planning, drilling, and postdrilling phases of the well. A geomechanics model determines the safe mud weight operating window and casing points, whereas the hydraulics model simulates ECD for defined mud properties, drilling parameters, and wellbore geometry. A synthesis of the two models enables the previously mentioned information to be compared and merged before spudding the well. Real-time collaboration between models enables each model to be updated with pertinent information from the other, ensuring that drilling operations are performed within optimum mud weight and ECD constraints. The geomechanics model can use real-time ECD data from the hydraulics model when a pressure-while-drilling (PWD) tool is not being used. In turn, the hydraulics model requires updating when the safe mud weight limits are being exceeded. The two models can each use information from the other when performing the post-well analysis and planning for the next well. Both models are valuable tools when used individually, but they become powerful, superior companions when used in conjunction with one another.