| 摘要 |
<p>System for drilling from a water surface, of the type having means for exerting and maintaining on the drilling tool a bearing stress, which is constant and normal to the surface to be perforated, no matter what the effect of the swell, wherein it comprises in combination: a base having a central passage for the drill pipe string of a drilling apparatus, which is intended to rest on the sea bed and is elastically connected to means for receiving a cylindrical box; a column formed by a cylindrical tubular central guide, for permitting the passage and guidance of the drill pipe string of the drilling apparatus, the column being surrounded by an external cylindrical tubular envelope, the hollow annular space formed between the central guide and the envelope being subdivided into a tight member constituting the lower ballast, a tight intermediate member of variable length determined as a function of the mean value of the section of water under which drilling takes place, a tight member constituting an upper ballast and a head member, the total height of the column exceeding the maximum depth of the section of water, the lower cylindrical part of the column being shaped so that it is placed in the reception means of the base and the head member of the column supporting a platform for installing the drilling apparatus; and a barge moored to anchor lines on the site where drilling is to take place, which is provided with an annular collar for receiving with a clearance the head member of the column in order to permit both vertical sliding and tilting with respect to vertical of the head member.</p> |
