| 摘要 |
<p>A downhole tractor is provided that includes a housing and a first wheel assembly (20a) coupled to the housing that is operable to translate away from the housing in a first direction. The first wheel assembly has a first electric motor, a first wheel, and a first reduction gear assembly coupled between the first electric motor and the first wheel. A second wheel assembly (20b) is coupled to the housing and is operable to translate away from the housing in a second direction that is opposite to the first direction. The second wheel assembly has a second electric motor, a second wheel, and a second reduction gear assembly coupled between the second electric motor and the second wheel. A fluid ram (364) is coupled to the first and second wheel assemblies for selectively translating the first and second wheel assemblies toward and away from the housing.</p> |
