| 摘要 |
A telescoping four-sided drilling derrick (20) and method or erection that is to be positioned on a drill floor (F) over a well bore and is capable of withstanding severely adverse weather, environmental or geologic conditions. The derrick (20) is in several sections and includes a bottom section (22), a top section (30) and at least one intermediate section (26, 28) all for superpositioning over the bottom section (22) to form a vertical four-sided tower. Each of the sections is composed of vertical members positioned in each of the four corners (38a-38d) of each section to thereby form a total of four faces (40a-40d) around the perimeter of each section. A window (46) is one face sufficiently large to receive consecutively therebelow at least one section. In turn each of the intermediate sections (26, 28) is inserted within the bottom section (22) for subsequent serial telescopic raising of the intermediate sections (26, 28). |
