Patent ID: 8256532
Filing Date: 2012-09-04
Classification: E21B

Abstract:
1. A method of controlling drilling fluid pressures, the method comprising the steps of: for each of a plurality of longitudinally separated locations of interest within a drilling system extending within a wellbore: forming pressure volume and pressure volume time curves for the respective longitudinally separated location of interest responsive to measured fluid pressure data and measured volume data; determining a change in fluid volume for fluid circulating portions of the drilling system, the change in fluid volume attributable to at least one of the following: fluid kick and drilling system component breathing and ballooning; differentiating between fluid kick and drilling system component breathing and ballooning when performing drilling operations responsive to the respective pressure volume and pressure volume time curves and earth formation compressibility data at a respective one of the plurality of locations of interest and at each longitudinally prior one of the plurality of locations of interest; and responsive to the step of differentiating, controlling drilling system downhole pressure realtime when performing the drilling operations.