| 摘要 |
The present invention is a system and method for measuring borehole conditions, in particular for verification of a final diameter of a borehole. The system includes a drill string with a drill bit and a drilling mud circulation device, an underreamer attached to the drill string above the drill bit, and a tool body attached to the drill string, having a sensor for detecting downhole conditions, such as borehole diameter. The tool body is mounted above the underreamer and has a diameter smaller than the underreamer and drill bit. The sensor can be an ultrasonic transducer with a sensor housing for adjustable distance to particular borehole size. The system may also include a calibrator for sensor data, and an auxiliary tool body with another sensor between the drill bit and the underreamer. |
| 主权项 |
1. A system for measuring borehole conditions, the system comprising:
a drill string having a bottom hole assembly with a drill bit at a terminal end thereof and a circulation means for drilling mud; an underreamer attached to the drill string above the drill bit and having a passage for flow of the drilling mud, the underreamer being comprised of a reamer body and a plurality of reaming blades, the reaming blades having cutting surfaces so as to contact and ream walls of the borehole, enlarging the borehole after drilling by the drill bit; and a tool body being mounted above the underreamer and having a set diameter smaller than the underreamer so as to avoid contact with walls of the borehole and to maintain rigidity of the drill string, the tool body comprising:
a sleeve being comprised of a tubular member;a sensor body with a means for detecting downhole conditions on an outer surface of said sensor body, said sleeve being affixed onto said sensor body and being connected to said sensor body, wherein said tool body has an inner passage for flow of the drilling mud through said sleeve and said sensor body; anda means for attachment to the drill string on said sleeve and said sensor body, wherein the tool body is rotatably and axially aligned with the drill string, the tool body being separate from the reamer body along the drill string, the flow of the drilling mud being along an outside of said sleeve and said sensor body and within the drill string through said inner passage of said tool body, wherein the circulation means for drilling mud has a mud flow line at a surface location, the system further comprising:
means for calibrating the means for detecting, the means for calibrating comprising:
a first ultrasonic transducer housed on said outer surface of said sensor body for measuring within said inner passage in fluid connection to the circulation system of the drilling mud through the drill string, the first transducer being contained in said sensor body with an orientation to measure inward toward said inner passage, the transducer oriented opposite said means for detecting downhole conditions; andprocessing means for comparing data from the first transducer so as to allow adjustment of drilling, wherein the first ultrasonic transducer measures within said inner passage for flow with a fixed gap spacing slot with a known diameter, transmitting a reading across the known diameter toward said inner passage from said outer surface of said sensor body during drilling so as to continuously record the reading across the known diameter for comparing drilling mud at the first ultrasonic transducer downhole to the drilling mud at the means for detecting downhole conditions; and wherein readings indicate need for an adjustment of readings of the means for detecting of the tool body. |
