| 摘要 |
The invention relates to a floating offshore rig (10) for drilling in a hydrocarbons containing formation below a body (B) of water, said rig (10) comprising: a deck structure (15) with a derrick (22) supporting a drill string, and a sub- structure including ballasting tanks (12) for said rig (10) and a number of leg or columns (20) for extending into said body (B) of water from said deck (15), said rig (10) including on said deck structure (15) a drilling mud pit (13) for supplying drilling mud to said drill string, at least one drilling mud holding tank (30) being located on said substructure and being connected with said drilling mud pit (13) via piping for transfer of said drilling mud between said mud holding tank (30) and said drilling mud pit (13), a vent line (32) extending from a top portion of said drilling mud holding tank (30) to a vent port (34) located at the level of said deck structure (15) at a height (H) above a bottom of said drilling mud holding tank (30), said drilling mud holding tank (30) com- prising at least one pressure sensor (S) for registering a hydrostatic pressure in said drilling mud tank (30) at or near the level of said bottom. |
