| 摘要 |
A method and apparatus for erecting a vertical mast 10 on a drill platform 15 with minimal reliance on existing cranes. An elevator guide section 20 is first constructed on the platform 15. The elevator guide section 20 has one open side for receiving the mast top section 40, mast bottom section 70, and one or more mast intermediate sections 58A-D, all of which, have approximately the same horizontal cross section. A pair of mast elevators 28A-B are slidably coupled to the elevator guide section 20. By means of the existing platform crane, the top section 40, which has a prestrung crown block 45 and travelling block 46, is placed within the elevator guide section 20 and on the elevators 28A-B. Lifting power is transmitted to the elevators 28A-B by the existing drawworks 52 via the travelling block 46. Through a series of vertical movements of the elevators 28A-B, the top section 40 is raised and one more intermediate sections 58A-D are stacked thereunder. After the last of the intermediate sections 58A-D is positioned under the top section 40, the bottom section 70 is lifted within the elevator guide section 20, and the top and intermediate sections 40, 58A-D are lowered thereon to form a complete mast 10 with sections of approximately the same horizontal cross section. |
