A number of parameters influence the development of gas kicks in oil based drilling muds. The dynamic effects of operating conditions (drilling rate, pump flowrate, well depth and casing depth), reservoir characteristics (permeability and formation pressure) and control methods (drillers and wait and weight methods) have been studied with a dynamic simulator for gas kicks in oil based muds. The model accounts for the effect of pressure, temperature and gas solubility on the mud density, and the mass and momentum balance equations are solved to give the detailed pressure and flowrate distribution in the well as a function of time.
The control phase is studied in two kick cases; a distributed kick and a concentrated kick. A perfect control is performed using wait and weight and drillers methods, and the corresponding surface and casing shoe pressures are analyzed.
The study also identifies the most sensitive parameters for kick development, and gives guidelines on how to optimize the drilling operations related to well control.
The simulations are also analyzed with relation to early surface detection of kicks, and the most sensitive detection parameters are identified.