US 12,006,789 B2
Float valve assembly for drilling and workover operations
Naif Mohsen Mosleh Alharbi, Dammam (SA); and Mohammed A. Jathmi, Dhahran (SA)
Assigned to Saudi Arabian Oil Company, Dhahran (SA)
Filed by Saudi Arabian Oil Company, Dhahran (SA)
Filed on Mar. 3, 2022, as Appl. No. 17/686,175.
Prior Publication US 2023/0279738 A1, Sep. 7, 2023
Int. Cl. E21B 34/10 (2006.01); C09D 5/00 (2006.01); C09D 7/40 (2018.01); E21B 21/10 (2006.01)
CPC E21B 34/10 (2013.01) [C09D 5/00 (2013.01); C09D 7/67 (2018.01); E21B 21/10 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A float valve assembly configured to be positioned within in a central bore of a tubular string disposed in a wellbore drilled into a subterranean zone, the float valve assembly comprising:
a valve main body comprising:
an outer surface substantially cylindrical in shape;
a valve flow passage defined in part by an inner surface of the valve main body and configured to be fluidically connected to the central bore; and
a circumferential inner sealing surface formed on a portion of the inner body surface; and
a plunger positioned within the valve main body and axially moveable therein, the plunger comprising:
a circular base;
a seal ring disposed circumferentially about the circular base; and
a plunger main body disposed on the circular base, a surface of the plunger main body comprising a plurality of substantially flat lateral faces forming a pyramid;
and wherein:
the plunger is biased, by a spring, towards a closed position in which at least a portion of the seal ring is in contact with the circumferential inner sealing surface, thereby preventing a flow of fluid in an uphole direction through the valve flow passage;
the plunger is configured to, in response to a fluid pressure in a downhole direction overcoming a biasing force of the spring, move to an open position in which the seal ring is not in contact with the circumferential inner sealing surface, thereby permitting a flow of fluid in a downhole direction through the valve flow passage; and
a hydrophilic nano-coating comprising particles with sizes of between 1 and 100 nanometers is disposed on at least a portion of the surface of the plunger main body.