| 摘要 |
<p>The rate of penetration of a drill bit and associated drill string used in drilling oil and gas wells is monitored and the resulting output signal activates an alarm whenever the rate of penetration exceeds a predetermined level. The depth of penetration is also monitored during the time that the rate of penetration is excessive and when the depth interval during such time exceeds a given number of feet, a second alarm is sounded. When the depth interval during the excessive rate of penetration is greater than a second predetermined number of feet, a signal is sent to the drawworks which takes the weight off the bit. Means are also provided for resetting the depth counting mechanisms whenever either of the depth interval circuits have counted to less than their predetermined capacity whenever the rate of penetration has diminished to a point which is less than the predetermined excessive level. In an alternative embodiment, predetermined time intervals are used instead of depth intervals.</p> |
