Chapter Two – Rig Calculations

This chapter presents the basic calculations used in drilling operations. It illustrates the equations needed to calculate the accumulator capacity including usable volume per bottle, surface application, deepwater applications, and accumulator precharge pressure. It also provides an understanding of calculating the bulk density of the cuttings using the mud scale balance. It provides a detailed procedure that can be used to design and select the drill string for drilling the well. This includes determining the maximum length of drill pipe that can be used based on maximum overpull and slip-crushing calculations. This leads to finding the depth of a washout in the string and calculating the depth of stuck pipe. Stuck pipe overbalance guideline calculations are shown with examples ending with calculations required for spotting treatment pills to free stuck pipe.