Tender Barge for Drillship Operating in Environmentally Sensitive Areas

Abstract

A tender barge for a drill ship includes a hull internally segmented into compartments. The compartments are for storing wellbore drilling consumables and wellbore drilling waste. The hull has an opening therein for positioning under a moon pool of a drill ship. The barge hull further includes a support structure for contacting a bottom of a hull of a drill ship when the drill ship is positioned over the barge hull. The barge has a mooring system having capacity to either hold the barge in position or hold both the barge and the drill ship when the drill ship is fully supported by the barge out of the water over a wellbore location.

What is claimed is: 
     
         1 . A tender barge for a drill ship, comprising:
 a hull internally segmented into compartments, the compartments for storing wellbore drilling consumables and wellbore drilling waste, the hull comprising an opening therein for positioning under a moon pool of a drill ship;   a support structure for contacting a bottom of a hull of a drill ship when the drill ship is positioned over the barge hull; and   a mooring system having capacity to at least one of holding the barge in position and holding the barge and the drill ship supported thereon over a wellbore location.   
     
     
         2 . The tender barge of  claim 1  further comprising ballast compartments having sufficient volume such that when deballasted provide sufficient buoyant force to support the weight of the drill ship completely out of a body of water. 
     
     
         3 . A method for drilling a wellbore using a drill ship and a tender barge, comprising:
 moving the tender barge to a well drilling location;   mooring the tender barge;   moving the drill ship so that a moon pool therein is positioned over a corresponding opening in a hull of the tender barge; and   deballasting the tender barge until a support structure on the hull thereof contacts a corresponding structure on a bottom of the drill ship.   
     
     
         4 . The method of  claim 3  wherein the deballasting provides sufficient buoyant force to support the drill ship completely out of a body of water. 
     
     
         5 . The method of  claim 3  further comprising drilling the wellbore, ballasting the tender barge, moving the drill ship away from the tender barge, deballasting and unmooring the tender barge, and moving the tender barge away from the well location.