CPC E21B 43/123 (2013.01) [E21B 34/10 (2013.01); E21B 2200/02 (2020.05)] | 20 Claims |
1. A spool valve assembly for use downhole to control fluid flow into a borehole from a downhole formation, comprising:
a valve body comprising an interior; and
a spool moveable within the valve body interior from a first position wherein the spool prevents flow through the valve body, to a second position wherein the spool allows flow through the valve body at a first flow rate, and to a third position wherein the spool allows flow through the valve body at a second flow rate different than the first flow rate,
wherein the spool is moveable from the first position to the second position using hydrostatic fluid pressure acting on the spool from outside the valve body, and
wherein the spool is moveable from the second position to the third position using gas pressure from a chemical reaction producing a force sufficient to overcome the hydrostatic pressure.
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