초록 ▼

A stabilized spar buoy construction for deep sea operations including an elongated submerged hull having a selected volume and a selected water plane area, mooring lines connecting the bottom portions of the hull with the sea bottom, said hull having oil storage chambers and variable ballast chamber

A stabilized spar buoy construction for deep sea operations including an elongated submerged hull having a selected volume and a selected water plane area, mooring lines connecting the bottom portions of the hull with the sea bottom, said hull having oil storage chambers and variable ballast chambers to establish and maintain a constant center of gravity of the spar buoy at a selected distance below the center of buoyancy of the spar buoy, a riser system extending through a through passage-way in the hull, a riser float chamber having pitch oscillations of the same amplitude as the hull and maintaining tension on the riser system and minimizing pitch motions therein, the bending stresses in the riser system between the sea floor and the riser float chamber being minimized by maintaining a selected constant distance between the center of gravity and the center of buoyancy under different load conditions of the spar buoy, said variable ballast chambers in the hull extending above the oil storage chambers. A method of maintaining constant draft and constant selected distance between the center of gravity and center of buoyancy of a spar buoy.

대표청구항 ▼

In a floating structure including oil storage capacity and production facilities and adapted to be anchored by catenary mooring lines at a subsea well location, the combination of: a vertical elongated hull means having means to maintain the hull means in vertical position; said hull means including

In a floating structure including oil storage capacity and production facilities and adapted to be anchored by catenary mooring lines at a subsea well location, the combination of: a vertical elongated hull means having means to maintain the hull means in vertical position; said hull means including a vertical oil storage chamber means for storing oil and extending for a major portion of the height of the floating structure; a plurality of vertical variable ballast chamber means extending from the bottom of the storage chamber means to above the top of the oil storage chamber means and selectively filled with ballast to maintain the center of gravity of the structure a selected distance from the center of buoyancy of the structure; work chamber means in said hull means above said oil storage chamber means; means in the work chamber means and in the variable ballast chamber means for controlling the amount of ballast in the variable ballast means; means in the oil storage chamber means and in the work chamber means for feeding oil to said oil storage chamber means and for removing water therefrom as oil is introduced therein; a central longitudinal passageway through the hull means; a riser means extending into said passageway from said subsea well location and terminating at said work chamber means; said riser means including buoyant tank means carried at the upper end thereof to maintain said riser means under tension; means on said riser buoyant tank means and on said hull means in said central passageway for guiding relative movement between said hull means and said riser means; said controlling means for said variable ballast chamber means being operable to maintain said floating structure under conditions of constant draft and constant distance between center of gravity and center of buoyancy to stabilize such relative movement.