CLEAN OUT SUB

摘要

A clean out sub for use in a drill string having a tool body with a cavity for passage of drilling fluid and annular fluid circulation ports extending through the tool body, a valve spool is positioned within the tool body cavity having a reduced diameter orifice, a compression spring is located within the tool body cavity adjacent the valve spool, wherein a drop in fluid pressure created by the orifice imparts a downhole force on the valve spool and at a predetermined force overcomes a set resistive force of the compression spring thereby moving the valve spool to open the annular fluid circulation ports.

主权项

1. A clean out sub for use in a drill string comprising:
a tool body having a tool body cavity for passage of drilling fluid through the clean out sub; a plurality of annular fluid circulation ports extending through the tool body to vent drilling fluid out of the tool body cavity; a valve spool positioned within the tool body cavity having an uphole end with a reduced diameter orifice; a compression spring located within a spring cavity positioned between the tool body cavity and the valve spool; spring cavity pressure supply ports extending through the valve spool; and spring cavity bleed ports extending through the tool body;
wherein a drop in drilling fluid pressure created by the orifice imparts a downhole force on the valve spool and at a predetermined force overcomes a set resistive force of the compression spring thereby moving the valve spool downhole to close the spring cavity pressure supply ports, vent the spring cavity through the spring cavity bleed ports and open the annular fluid circulation ports.