Comparing vertical and horizontal drilling in well control in oil and gas

Abstract

A brief introduction is given to a range of well control procedures. It was found that many of the procedures rely on a set of simplifying assumptions. This is particularly true in the hand calculations for designing a well kill. This set of assumptions was used to define an analytical model. The premises of the analytical model and some of the procedures were tested in a well control simulator. The main objective of this thesis was to verify some of the well control procedures, and to shed light on their limitations. Particular attention was given to well control methods for a vertical and horizontal well. The aim of the project is using the well control simulator to compare the vertical and horizontal drilling operation in oil and gas exploration. The study involves drilling technology, well design and construction, with reference to collating and comparing data when the two-drilling simulation were performed. Further modifications deemed necessary: • Improved accuracy in reading of bottom hole and choke pressures. • Implementation of additional topside parameters (pit gain, drill pipe pressure) • A more realistic friction model. • Changing the liquid component of the system from water to drilling fluid (altering the liquid density). The results obtained by the kick simulator were compared to hand calculations. The main discovery was that although the hand calculations produce slight errors, the errors exclusively functions as additional safety margins with respect to downhole pressure differential. It was also found that a gas bubble migrating in a shut-in annulus subjects the well to higher loads than the gas filled well scenario.