| 摘要 |
In the process of recovering minerals, such as hydrocarbons from shallow tar sands, and the like, one method is to create a shallow horizontal fracture within the tar sand. The size and shape of the perimeter is determined, and one or more secondary boreholes are drilled to the formation inside of the perimeter of the fracture. Pressurized air is injected into the fracture and the hydrocarbons are ignited. After a selected period of burning is carried out, the radius to the burn front, surrounding the recovery area, from which the hydrocarbons have been removed, is determined by placing a source of seismic waves at a selected point over the fracture, and a long array of seismic sensors colinear with the source. The source is energized for different conditions of pressurization in the formation and fracture. The reflected seismic waves are converted to electrical signals, which are compared for all sensors. By comparison of the character and/or energy of the reflections, the geometry of the burn zone can be determined.
|
