US 11,987,443 B2
Subsea fluid storage unit
Morten Saeterdal, Klepp St. (NO); and Sigbjorn Daasvatn, Hornnes (NO)
Assigned to SUBSEA 7 NORWAY AS, Stavanger (NO)
Filed by Subsea 7 Norway AS, Stavanger (NO)
Filed on Oct. 15, 2021, as Appl. No. 17/502,858.
Application 17/502,858 is a division of application No. 17/259,039, previously published as PCT/EP2019/068294, filed on Jul. 8, 2019.
Claims priority of application No. 1811237 (GB), filed on Jul. 9, 2018.
Prior Publication US 2022/0033177 A1, Feb. 3, 2022
Int. Cl. B65D 88/78 (2006.01); B63B 25/16 (2006.01); B63G 8/42 (2006.01); B65D 88/00 (2006.01); B65D 88/18 (2006.01); B65D 88/74 (2006.01); B65D 90/04 (2006.01); B65D 90/24 (2006.01); E21B 43/01 (2006.01); E21B 43/017 (2006.01)
CPC B65D 88/78 (2013.01) [B63B 25/16 (2013.01); B63G 8/42 (2013.01); B65D 88/005 (2013.01); B65D 88/18 (2013.01); B65D 88/744 (2013.01); B65D 90/24 (2013.01); B63G 2008/425 (2013.01); B65D 90/046 (2013.01); E21B 43/0122 (2013.01); E21B 43/017 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A subsea fluid storage unit, comprising:
a variable volume inner tank having a rigid top panel and a peripheral wall that is extensible and retractable in a vertical direction to vary a height dimension of the tank while the tank remains of substantially unchanged width in a horizontal direction; and
a side wall surrounding and spaced from the peripheral wall of the inner tank in the horizontal direction to define a floodable gap that surrounds the tank between the peripheral wall and the side wall and that has a closed top, wherein the side wall is contiguous with a base to define a floodable enclosure extending beneath the inner tank, and the rigid top panel of the inner tank is supported by the side wall, wherein the side wall is surmounted by a support flange, wherein the support flange of the side wall supports a hanging flange of the rigid top panel that projects beyond the peripheral wall in the horizontal direction and wherein the hanging flange of the rigid top panel is fixed to the support flange of the side wall with ROV-accessible clamps or locking pins;
wherein the inner tank closes an open top of the enclosure and is closed by a bottom plate that extends in the horizontal direction along a bottom edge of the peripheral wall, wherein the bottom plate projects beyond the peripheral wall in the horizontal direction such that a clearance between the bottom plate and the side wall is narrower horizontally than the floodable gap.