Process of installing compliant offshore platforms for the production of hydrocarbons

Abstract

To produce hydrocarbons from an offshore production site, a well is drilled into hydrocarbon bearing strata from a non-permanent floating vessel and is then capped. Keying off a template positioned on the well, a base unit is attached to the seabed by driving foundation piles therethrough into the seabed. A tower is installed onto the base unit by attaching lower ends of flex legs of the tower with upper ends of respective foundation piles at locations above the seabed. A deck and topsides are installed to an upper end of the tower. The platform need not be fully compliant until the topsides are installed and operational.

1 . A process of producing hydrocarbons from a subterranean reservoir beneath a body of water, said process comprising the steps of: 
 A. drilling a well with a non-permanent drilling apparatus;    B. positioning a drilling template on a structural casing string of the well;    C. finishing the well into hydrocarbon bearing strata;    D. capping the finished well and removing the non-permanent drilling apparatus;    E. keying off the drilling template to install a production platform extending above the water surface; and thereafter    F. operably connecting production equipment of the platform to the finished well for production of hydrocarbons therefrom.    
   
   
       2 . The process according to  claim 1  wherein step E comprises installing a fully compliant production platform.  
   
   
       3 . The process according to  claim 1  wherein step E comprises installing a tower extending upwardly past the water surface, mounting a deck onto the tower, and mounting topsides onto the deck, wherein the installed tower is non-fully compliant, and the combination of the tower, the deck, and the operational topsides is fully compliant.  
   
   
       4 . The process according to  claim 1 , wherein step E comprises installing a tower extending upwardly past the water surface, mounting a deck onto the tower, and mounting topsides onto the deck, wherein the installed tower is fully compliant prior to mounting the deck and the topsides.  
   
   
       5 . The process according to  claim 1  wherein step E includes driving rigid foundation piles through respective guides keyed off the drilling template, and mating flex legs of the tower with respective foundation piles and permanently attaching the flex legs to the foundation piles at respective locations above the seabed and below the water surface.  
   
   
       6 . The process according to  claim 1  wherein step E further includes keying off the drilling template to install a leveling pile template, driving leveling piles through respective guides of the leveling pile into the seabed, supporting a tower base template on the leveling piles of the leveling pile template, leveling the tower base template using pile shims and/or hydraulic jacks, driving rigid foundation piles through respective guides of the tower base template into the seabed, mating the flex legs of the tower with respective foundation piles, and permanently attaching the flex legs to the foundation piles at a respective locations above the seabed and below the water surface.  
   
   
       7 . The process according to  claim 6  wherein the leveling pile jacks are retracted after the leveled tower base template is supported by the foundation piles.  
   
   
       8 . The process according to  claim 1 , wherein additional wells are drilled from the platform and completed into hydrocarbon strata subsequent to step B and prior to step F.  
   
   
       9 . The process according to  claim 1 , further including the step of producing hydrocarbons from the formation following step F.  
   
   
       10 . The process according to  claim 9 , further including processing the produced hydrocarbons for uses selected from the group consisting of storage, transportation, further refining, and combinations thereof.  
   
   
       11 . A process of installing a compliant offshore platform comprising the steps of: 
 A. attaching a platform base unit to the seabed by driving rigid foundation piles into the seabed;    B. mating flex legs of a tower with respective foundation piles and permanently attaching the flex legs to the foundation piles at respective locations above the seabed and below the water surface; and    C. installing a tower on the base unit,    wherein step A comprises attaching to the seabed a base unit comprised of a drilling template positioned on a pre-drilled well, keying off the drilling template to position a leveling pile template on the seabed, and positioning a tower base template on the leveling pile template and supporting the weight of the tower base template by the leveling piles, and wherein the foundation piles are driven through guides of the tower base template in step A.    
   
   
       12 . The process according to  claim 11  wherein the leveling pile jacks are retracted after the leveled tower base template is supported by the foundation piles.  
   
   
       13 . The process according to  claim 12 , further including the step of producing hydrocarbons from the formation.  
   
   
       14 . The process according to  claim 13 , further including processing the produced hydrocarbons for uses selected from the group consisting of storage, transportation, further refining, and combinations thereof.  
   
   
       15 . The process according to  claim 11  wherein the water depth is not greater than 1300 feet.  
   
   
       16 . A process of producing hydrocarbons from a subterranean reservoir beneath a body of water having a depth not greater than 1300 feet, said process comprising the steps of: 
 A. drilling a well with a non-permanent drilling apparatus;    B. positioning a drilling template on a structural casing string of the well;    C. finishing the well into hydrocarbon strata prior or subsequent to step B;    D. capping the finished well and removing the non-permanent drilling apparatus;    E. installing a production platform on the seabed over the capped well by: 
 C1. attaching a base unit to the seabed,  
 C2. installing a tower on the base unit, thereafter  
 C3. mounting a deck on the tower above the water surface, thereafter  
 C4. attaching topsides to the deck, and thereafter  
 C5. operably connecting production equipment of the platform to the capped well for production of hydrocarbons therefrom;  
   wherein the platform is non-fully compliant following each of steps C1 to C4, and is fully compliant following step C5.    
   
   
       17 . The process according to  claim 16 , further including the step of producing hydrocarbons from the formation.  
   
   
       18 . The process according to  claim 16  wherein step C1 comprises attaching the base unit to the seabed by driving foundation piles therethrough into the seabed, and step C2 includes mating lower ends of flex legs of the tower to upper ends of respective foundation piles at respective locations above the seabed, and affixing the flex legs to the foundation piles.  
   
   
       19 . The process according to  claim 18  wherein the leveling pile jacks are retracted after the leveled tower base template is supported by the foundation piles.  
   
   
       20 . The process according to  claim 11 , wherein step A comprises attaching to the seabed a base unit comprised of a leveling pile template on the seabed, and positioning a tower base template on the leveling pile template; wherein the foundation piles are driven through guides of the tower base template in step A.