Development of an underbalanced drilling optimization simulator (udos)
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2012
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Abstract
Drilling simulation technology has been widely applied m many drilling engineering areas to solve drilling problems, optimize drilling parameters, and to train engineers with real drilling operations as well as to handle rare applications and accidents. The rising application of Under-Balanced Drilling (UBD) especially in western Canada creates a demand for a UBD simulator tool which enables the drilling engineers to simulate the drilling operations in a pre-planning mode. UBD is a procedure used to drill oil and gas wells where the pressure in the well bore is kept lower than the pressure of the formation being drilled. This results in many advantages over conventional drilling such as higher rate of penetration (ROP), prevention of fluid losses and formation damage. The research presented in this thesis includes the development procedure a new UBD simulator. This simulator includes a procedure on how to process the drilling and reservoir data to be able to predict the reservoir influx and calculate the corresponding bottom hole pressure (BHP) and surface back pressure (BP) during the drilling of a well. The mathematical modeling in the simulator is based on a new comprehensive mechanistic steady state model. The results produced by the simulator are compared to available field drilling operational data. This new simulator is the first developed multiĀpurpose underbalanced drilling optimization simulator integrating the underbalanced drilling technique, field operational parameters and bit performance optimization. The pre-planned safe operational window is the most important output of the simulator. Also, a new correlation is developed which correlates the drilled underbalanced rock strength to the unconfined rock compressive strength (UCS). The UCS can further be used as an input into available drilling rate of penetration (ROP) optimization simulators. Using the rate of penetration models to back-calculate the UCS provides the user with the possibility of calculating the rock mechanical UCS value for any PDC bit with corresponding operating parameters and any underbalanced drilling mode. The preplanned safe pressure window any underbalanced drilling technique guarantees adequate hole cleaning. Finally, the results from the simulator are compared to and found to be in good agreement with available field data. Using the simulator can provide an inexpensive mean to assist with the design of safe and economical underbalanced drilling operations.
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Bibliography: p. 193-199
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Citation
Shirkavand, F. (2012). Development of an underbalanced drilling optimization simulator (udos) (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/4724