| 摘要 |
A ground fracturing probe to form fractures in subsurface formations includes an elongate, hollow body with a conical penetrating tip at its distal end. A threaded tool joint is at the other end of the body to allow the probe to be coupled to the drill string of a drilling rig. A helical flight is on the exterior surface of the body and extends along a portion of the body length between the tool joint and the penetrating tip. The helical flight varies in diameter over its length to define a cutting zone adjacent the penetrating tip, an injection zone above the cutting zone and a sealing zone above the injection zone. The helical flight increases in diameter in the cutting zone from the tip to the injection zone but decreases abruptly in diameter at the injection zone. The diameter of the flight remains constant in the injection zone and increases in diameter at the interface between the injection zone and the sealing zone. The diameter of the flight remains constant over the length of the sealing zone but is greater in diameter in the sealing zone than in the cutting zone. Orifices are provided in the body within the injection zone and communicate with the interior of the body to allow fluid pumped into the body under pressure to be discharged. The increased diameter of the flight in the sealing zone inhibits discharged fluid from travelling to the ground surface along the probe. |
