Position determining and dynamic positioning method and system for floating marine well drill platforms and the like
US4205379A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 9, 1978 |
| Grant date | May 27, 1980 |
| Priority date | — |
| Expiry date | May 9, 1998 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02B2075/027
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The relative horizontal positions of a floating marine platform and the lower end of a flexible connecting line, such as a cable, drill string, or well bore riser, suspended from the platform are determined by generating angle signals representing the instantaneous vertical slope angles of the connecting line at or near its upper and lower ends, filtering these signals to remove higher order frequencies resulting from variable forcing functions, such as surface wave induced motion of the platform, which produce no net change in the platform position, whereby the filtered angle signals represent the mean terminal slope angles of the envelope of the undulating connecting line, and combining these filtered angle signals in accordance with a predetermined position equation which compensates for phase lag between the sensor measured and true positions of the platform due to the transit time of platform motion induced stress waves or undulations along the connecting line to the lower angle sensor. The invention is described in the context of positioning a floating oil well drilling or producing platform relative to an ocean floor well head.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.