Development of a Novel Hybrid-Type Rotary Steerable System for Directional Drilling
Unlike conventional resources, unconventional resources, such as shale gas and coal bed methane, are situated horizontally under geological formations. To exploit these resources, directional drilling and hydraulic fracturing technologies are required. In directional drilling, the dog leg severity (DLS), which indicates how much the angle changes while drilling 100 ft, is a major issue with respect to the cost and time of drilling. In this paper, we briefly review different types of directional drilling methods and propose a new hybrid-type rotary steerable system (RSS). DLS calculations based on three-point geometry for these systems are suggested. This hybrid RSS combining two conventional types of RSSs: point-the-bit and push-the-bit systems, achieves better steerability. The hybrid mechanism is implemented using hybrid pads with hydraulic cylinders and a spherical joint. The advantages of the proposed system are demonstrated by performing small-scale prototype and cement block drilling tests.
Toolface Control Method for a Dynamic Point-the-Bit Rotary Steerable Drilling System
In the dynamic point-the-bit rotary steerable system (DPRSS), a high dynamic stiffness toolface control method is desired to ensure the stabilized platform traces the directional command accurately and quickly. A three-loop compound toolface control method using the Model-based Active Disturbance Rejection Control (MADRC) algorithm is presented, and a load torque estimator and an outer housing speed estimator are designed based on system model to obtain the external disturbances. The proposed toolface control method was verified by numerical simulation and DPRSS prototype testing, and its speed loop frequency responses are analyzed. The results reveal that this method is effective in disturbance rejection and robust against parameter uncertainties, and the MADRC shows better performance compared with the conventional ADRC and the proportional-integral (PI) controller. The proposed method has the potential to be used in harsh drilling conditions.
Byron: Augustan and Romantic
The impact of Byron's writings - an evaluative approach, William St Clair "My brain is feminine" - Byron and the poetry of deception, Jerome J. McGann Byron and the romantic heroine, Malcolm Kelsall Byron and the Empire in the East, Marilyn Butler Byron Augustan - mutations of mock-heroic in "Don Juan" and Shelley's "Peter Bell the Third", Claude Rawson continuities and discontinuities of language and voice in Dryden, Pope, and Byron, Bernard Beatty Augustan satires and Panegyrics on London and Byron's image of the city, Michael Gassermeier Byron, Pope, and the Grand Tour, Michael G. Cooke Byron in Italy - the return of Augustus, Donald H. Reiman "Don Juan" transformed, Anne Barton Byron's "Wrong Revolutionary System" and romanticism, Hermann Fischer the quintessential Byron, Leslie A. Marchand.