The application of managed pressure drilling (MPD) is becoming more widely spread throughout the world. It is well known that MPD has less hydrostatic head during drilling therefore the rate of penetration (ROP) is increased. This is due to the reduced rock confinement and chip hold down effects. By simulating the conventional drilling and MPD of a well in advance the benefits of MPD can be quantified in terms of increase in ROP and therefore the economical benefits. Applying a commercially available drilling simulator (1)meter by meter drilling performance is analyzed, first simulating and optimizing a conventional drilling operation and then performing the same procedure for a MPD operation in Western Canada. The additional costs of the MPD operation are integrated into the economical analysis. The analysis shows that the ROP during MPD in the higher mud weight regime of the well is improved from 60 to 80 percent. In addition to the faster drilling during MPD the drill bits last longer due to the lesser hardness of the rock being less confined and therefore also reducing the amount of bit wear and the number of bits required and tripping time. Overall the results indicate that the MPD operation reduce the drilling cost of gas wells in Central Alberta more then 20 percent and due to the reduced time at the location less environmental impact is seen.
The first objective of this exercise was to develop a "base case" drilling simulation from which subsequent optimization simulations could be run. An apparent rock strength log (ARSL) was developed based on actual drilling data and formed the backbone of all subsequent calculations. The second objective of the exercise was to compare the non-optimized base case (as above) with an optimized base case. Based on previous experience, drilling economics should improve by approximately 25%. The third and primary objective of this exercise was to compare the optimized base case with an optimized Managed Pressure drilling (MPD) case and, if possible, to justify the additional cost of implementing MPD technology.
