Optimum drilling conditions have to date been determined using either trial and error at the rigsite or by repetitive and time consuming calculations, generally involving a number of different PC based programs. Calculating optimum drilling fluid flowrate conditions to ensure the highest possible penetration rate for example, involves manipulating variables such as drillstring configuration, nozzle diameters and mud properties to satisfy constraints such as the ability to clean the hole, bit specific energy, system pressure distribution and rig capability. This optimization process is ideally suited to automation, however, the number of variables and constraints on the problem requires careful design of the user interface.
This paper describes the development of a Hydraulics and Hole Cleaning Application which combines the use of X-window graphical features in an interface with engineering models that faithfully describe hydraulics and hole cleaning. The application uses the engineering models, derived from extensive research, to provide a rapid assessment of operating parameters such as pump pressure, pressure at the previous casing shoe and cuttings cleaning capacity and provides a graphical summary of this information for comparison with drilling constraints. It thus provides an environment for rapid determination of optimum operating conditions.
Described in the paper are the processes employed to translate the routine drilling engineering task into an application oriented to the drilling engineer in the field. This was largely achieved through the design of the user interface. The paper describes the evolution of a number of the features of the interface from original concepts and specifications which were modified as feedback from field use became available. The structure of the current application is described together with examples of typical field output.