Offshore drilling platforms are exposed to wind, waves, currents, and other unknown disturbances. Accurately estimating and rejecting these disturbances is the key to ensuring reliable station-keeping of the platforms. In this study, a novel dynamic positioning method using an improved equivalent-input-disturbance (EID) approach is proposed for offshore drilling platforms. An improved EID estimator is employed to estimate and suppress unknown disturbances, significantly enhancing the disturbance-rejection performance of the dynamic positioning system. The input channels are decoupled through linear transformation, and the parameter tuning process of the observer and controller is optimized, thus improving system performance. The bounded-input bounded-output stability of the closed-loop system is proved. This study provides insights into the design of dynamic positioning systems for offshore drilling platforms.
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http://dx.doi.org/10.1016/j.isatra.2024.02.012 | DOI Listing |
Sci Rep
January 2025
Geophysics Department, FacultyofScience, Cairo University, Giza, 12613, Egypt.
The Nile Delta, North Africa's leading gas-producing region, was the focus of this study aimed at delineating gas-bearing sandstone reservoirs from the Pleistocene to Pliocene formations using a combination of pre-stack inversion and rock physics analysis. This research employed seismic inversion techniques, including full-angle stack seismic volumes, well logs, and 3-D with rock physics modeling to refine volumes of P-wave velocity (Vp), S-wave velocity (Vs), and density. Traditional seismic attributes, such as far amplitude, proved insufficient for confirming gas presence, highlighting partial angle stacks, integrated the need for advanced methods.
View Article and Find Full Text PDFMar Pollut Bull
December 2024
Danish Offshore Technology Centre (DTU), - Elektrovej 375, 2800 Kgs. Lyngby, Denmark.
The offshore oilfields in the North Sea area are increasingly employed for projects beyond oil production, like carbon capture and storage (CCS). Still, the fossil fuel production from mature fields is significant. It has raised environmental concerns associated with discharging produced waters (PW) and drilling mud into the sea.
View Article and Find Full Text PDFAnn Work Expo Health
December 2024
STAMI, National Institute of Occupational Health, Gydas Vei 8, 0363 Oslo, Norway.
Objectives: Exposure to microorganisms is a known contributor to occupational disease. This study assessed drilling waste workers' health status and investigated the potential of inhalable bioaerosols to elicit an immune response in vitro and in vivo.
Methods: Venous blood and self-reported health data were collected from 56 and 73 Norwegian drilling waste workers, respectively.
ACS Omega
December 2024
PetroChina Dagang Oilfield Company, Tianjin 300280, China.
The Chenghai area is a secondary structural unit within the Qikou sag of the Bohai Bay Basin, located in the southern part of the Dagang offshore area, known for its abundant oil and gas resources. Influenced by multiple episodes of tectonic activity, the Chenghai area exhibits a highly developed fault system, which significantly impacts oil and gas exploration in the region. To investigate the structural characteristics of fault zones in the Chenghai area and their petroleum geological significance, this study builds upon previous research by utilizing oilfield drilling data and relevant seismic information.
View Article and Find Full Text PDFPLoS One
December 2024
School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing, China.
Characterizing anisotropy remains challenging in rock mechanics. Particularly, the strengths and failure patterns of layered shales under shear load are significantly anisotropic mainly because of the bedding planes. Meanwhile, understanding the creation and propagation of shear fractures is critical for drilling, mining, tunnelling, exploitation of shale gas, etc.
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