| 摘要 |
<p>1,033,051. Wells, &c. F. WHITTLE. Jan. 18, 1963 [Jan. 22, 1962], No. 2280/62. Heading E1F. An assembly enables plugging material carried by drilling mud to pass from a drill string to the walls of a borehole, and drilling mud to enter the string without the passage of the material or the mud through the bit. The assembly is interposed between the string and the bit, or between the string and the mud operated bit drive motor when the motor is adjacent the bit. Fig. 1 shows the assembly telescopically contracted for drilling when the bit takes the weight, and Fig. 2 shows the assembly telescopically extended for returning to the borehole filled with mud or for supplying the plugging material to the walls. The assembly comprises telescopic casing parts 1, 2 connected to transmit torque and having ports 12, 17 respectively for discharge of the plugging material and entry of the mud; a valve 5 for closing the ports 12 when the casing is contracted; a valve 26 for stopping flow of drilling mud outwardly through the ports 17 during drilling; means 18-21 for preventing rock debris entering the ports 17 with the mud; a valve 14 for closing the bore of the casing on extension of the casing; a valve 23 closing the bore to prevent mud from the ports 12 entering the string but opening the bore during drilling to permit mud to flow to the bit and during pumping of plugging material. In a modification the ports 12 are closed by an internal sleeve when drilling, and the ports 17 are closed by the lower part of the casing when drilling and by an internal sleeve attached to the valve 23 during pumping of the plugging material which comprises fibrous material, nut shells or flakes of cellulose film.</p> |
