Patent ID: 7134511
Filing Date: 2006-11-14
Classification: E21B

Abstract:
1. A method for working a soil area comprising the steps of: providing a drilling rod fitted with at least one tool; providing a hydraulic rotary motor for providing a rotary drive for rotating the drilling rod about a rotation axis; lowering the drilling rod into the soil area in the direction of the rotation axis by way of a feed drive having a feed rate; measuring, by use of a pressure sensor, the pressure of a hydraulic fluid supplied to the hydraulic rotary motor; calculating the rotation speed of the drilling rod by applying calculation instructions from a control device to the measured pressure, the calculating instructions responding to conditions that change the relationship between the rotation speed of the drilling rod and the pressure measured by the pressure sensor; and reducing the feed rate when the control device determines that there is a decrease in the rotation speed of the drilling rod.