Upgrading Offshore Wellhead Platforms

Abstract

Systems and methods for upgrading an offshore wellhead platform include identifying existing wells on an offshore wellhead platform that are capable to produce hydrocarbons for a specified time period; determining that an existing platform structure of the offshore wellhead platform is unable to accommodate additional loads from new equipment and upgrades when at least 50% of the existing wells on the offshore wellhead platform are capable to produce hydrocarbons for the specified time period; determining that the existing platform structure is unable to accommodate addition of two piles to support the additional loads from new equipment and upgrades; determining that the existing wells will handle horizontal loads when the existing platform structure is removed; and performing a slipover platform upgrade to the offshore wellhead platform when the existing wells will handle horizontal loads.

What is claimed is: 
     
         1 . A method for upgrading an offshore wellhead platform, the method comprising:
 identifying existing wells on an existing offshore wellhead platform that are capable to produce hydrocarbons for a specified time period;   determining that an existing platform structure of the existing offshore wellhead platform is unable to accommodate additional loads from new equipment and upgrades when at least 50% of the existing wells on the existing offshore wellhead platform are capable to produce hydrocarbons for the specified time period;   determining that the existing platform structure is unable to accommodate addition of two piles to support the additional loads from new equipment and upgrades;   determining that the existing wells will handle horizontal loads when the existing platform structure is removed; and   performing a slipover platform upgrade to the existing offshore wellhead platform when the existing wells will handle horizontal loads.   
     
     
         2 . The method of  claim 1 , wherein determining the ability of the existing wells to handle horizontal load comprises determining the ability of the existing wells to handle the horizontal loads using clamps to strengthen the existing wells. 
     
     
         3 . The method of  claim 1 , wherein performing the slipover platform upgrade comprises:
 demolishing the existing offshore wellhead platform while maintaining the existing wells in place;   removing the existing platform structure;   installing a new slipover platform structure; and   installing a new production deck module on the new slipover platform structure.   
     
     
         4 . The method of  claim 3 , further comprising installing new piles to support the slipover platform. 
     
     
         5 . The method of  claim 4 , wherein installing the new piles comprises installing the new piles with safe distances from existing piles and/or in a same direction as the existing piles to avoid clashing between the new piles and the existing piles. 
     
     
         6 . The method of  claim 1 , further comprising:
 determining that the existing platform structure is able to accommodate the additional loads from new equipment and upgrades; and   performing an in-place platform upgrade when the existing platform structure is able to accommodate the additional loads.   
     
     
         7 . The method of  claim 6 , wherein performing the in-place platform upgrade comprises installing new equipment on the existing offshore wellhead platform; and
 upgrading topside piping for the existing wells.   
     
     
         8 . The method of  claim 7 , wherein the new equipment comprises one or more of an electric switchgear, topside electric submersible pump equipment, transformers, and chemical injection systems. 
     
     
         9 . The method of  claim 1 , further comprising drilling new wells and constructing a new platform structure at a new location when the existing wells are unable to handle the horizontal loads or when fewer than half of the wells are capable to produce hydrocarbons for the specified time period. 
     
     
         10 . The method of  claim 9 , further comprising plugging and abandoning the existing wells on the existing offshore wellhead platform; and removing the existing offshore wellhead platform to free the space for future development or undergo a de-commissioning phase. 
     
     
         11 . The method of  claim 1 , further comprising:
 determining that the existing platform structure is able to accommodate the two additional piles to support the additional loads from the new equipment and upgrades; and   performing a two additional piles upgrade to the existing offshore wellhead platform when the existing platform structure is unable to accommodate the additional loads and the existing platform structure is able to accommodate the two additional piles.   
     
     
         12 . The method of  claim 11 , wherein performing the two additional piles upgrade comprises installing two piles on a side of the existing offshore wellhead platform to redistribute a current loading and support a new loading; and constructing a new portion for the existing offshore wellhead platform supported by the two additional piles. 
     
     
         13 . The method of  claim 1 , further comprising performing an auxiliary platform upgrade when the existing platform structure is unable to accommodate the additional loads from new equipment and upgrades, the existing platform structure is unable to accommodate the two additional piles, and the existing wells are unable to handle horizontal loads. 
     
     
         14 . The method of  claim 13 , wherein performing the auxiliary platform upgrade comprises building a new structure near the existing offshore wellhead platform to house new equipment for the existing offshore wellhead platform, wherein the new structure comprises a bridge to connect the new structure with the existing offshore wellhead platform. 
     
     
         15 . A method for upgrading an offshore wellhead platform, the method comprising:
 identifying existing wells on an existing offshore wellhead platform that are capable to produce hydrocarbons for a specified time period;   determining that half or more of the existing wells are capable to produce hydrocarbons for a specified time period;   performing a slipover platform upgrade when a construction risk for performing the slipover platform upgrade is less than a threshold risk, wherein performing the slipover upgrade comprises:
 demolishing the existing offshore wellhead platform while maintaining the existing wells in place; 
 removing an offshore wellhead platform structure; 
 installing a slipover platform structure; and 
 installing a new production deck module on the slipover platform structure. 
   
     
     
         16 . The method of  claim 15 , further comprising installing isolation plugs in the existing wells prior to performing the slipover platform upgrade. 
     
     
         17 . The method of  claim 15 , further comprising drilling additional wells to increase production of hydrocarbons. 
     
     
         18 . The method of  claim 17 , further comprising installing a temporary conductor guide to assist conductor installations on the additional wells. 
     
     
         19 . The method of  claim 17 , further comprising installing clamps to group well conductors for the existing wells prior to demolishing the existing offshore wellhead platform. 
     
     
         20 . The method of  claim 17 , wherein installing the slipover platform comprises:
 lifting the slipover platform; and moving the slipover platform into place over the existing wells.