Offshore Drilling - PowerPoint by Zxt5G32


									   First well drilled offshore :
     1897 off the coast of southern California
     Wooden pier extended 300’ into the Pacific Ocean
   Early Barges and Platforms:
     Seismic surveys in the 1930’s showed hydrocarbon
      formations in the marshlands, bayous and shallow
      bays next to the Gulf of Mexico.
     Oil companies dredged a 4’-8’ deep channel in
      marshes and bays then towed in a barge
     They sunk the barge and secured it using wooden
      pilings, then erected a rig on the deck above the
   Wooden Platforms
     Companies built
      wooden platforms on
      timber piles and
      erected rigs on top of
      the platforms
     Barges brought
      supplies out to the
      platform, or trestles
      were built from the
      shore to the platform
      creating a road for
      trucks to use.
   The first steel platform was built in
    1947 and installed in the Gulf of
    Mexico at a water depth of 20’.
   Operators anchored surplus
    barges and tenders to the sides of
    the platform.
   Barges/tenders carried supplies,
    living quarters, and circulating
   These platforms worked in water
    depths of less than 60’, and moved
    from well to well.
   Mobile Offshore Drilling Rigs
     1948 Naval architects and
        engineers designed a system
        consisting of a barge with
        several steel beams, or posts
        attached to its deck
       Drilling Equipment was
        installed on the deck
       When the rig arrived on
        location the lower part (barge
        hull) was allowed to fill with
        water in order to sink the rig
        to the sea floor
       The deck extended to the
        surface due to the posts
        attached to the barge
       Called: “Posted Barge Rigs”
   Moving further and deeper out to sea
   Justification to drill at greater depths
   Typical reserves needed for offshore/deepwater drilling is 300
    million barrels to offset cost and produce desired revenues.
   Drilling rigs differ for exploration and development wells.
   Exploratory: typically have mobile offshore drilling units
   Development Wells: typically use fixed platforms with production
    and well maintenance facilities
     New technologies are allowing the use of non-fixed units for
      development purposes.
   Typically classified in two categories:
     Submersibles
     Floaters
   Submersibles: Supported by the sea floor
       Posted Barges
       Bottle-type submersibles
       Arctic submersibles
       Jackups

   Floaters: Float on or just below the surface of the water
     Bottle-type Semisubmersibles
     Column-Stabilized Semisubmersibles
     Drill Ships
                     Bottle Type


Arctic Submersible
(Concrete Island
Drilling System)



                   Drill Ships

   Can be used anywhere especially in

   Rig is partially submerged to maintain

   Faster to move than submersibles

   Have very deep operating depths

   Are more susceptible to weather conditions
    and wave dynamics.
   Rigid Platforms: typical water depths of less
    than 1000’

     Steel Jacket Platform
      ▪ Tubular steel members and piles driven deep into the sea
        floor support the rig floor and all supporting, drilling
        equipment and personnel.
     Concrete Gravity Platform
      ▪ Built from steel reinforced concrete caissons (columns)
        support the structure above and because of weight do not
        require anchoring to the sea floor.
   http://www.youtu
   Designed for arctic conditions, drilling is completed through the
    legs of the rig in order to protect it from moving ice.
   Guyed Tower Platforms (Spar)

   Tension Leg Platforms
     Topside resembles a semi submersible, but the
      hull is attached to the seafloor via steel tubes
      called tendons
     New designs can drill in waters 4000’ deep and

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