文档介绍：Evolution of Offshore Drilling Units
Instructor
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Objectives
At pletion of this training module the engineer will:
Clearly be able to define a rig type with the environment it is best suited to
List pro/cons for the many types of rig available
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Where did Offshore Drilling Start?
In 1897, 38 years after Col. Drake’s well, . Williams drilled a well off a pier in the Santa Barbara Channel.
5 years later there were 150 wells “offshore” California.
By 1921 there were steel production piers that ran ½ mile offshore at Rincon and Elwood California.
In 1932 a steel pier island (60’ x 90’ with 25’ air gap) was built offshore California to support a drilling rig.
In 1938 a field was discovered offshore Texas and another well was drilled to 9,000 ft. off a wooden platform in 1941.
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Continued – Where did Offshore Drilling Start?
World War II stopped all offshore activity.
In 1945 Louisiana had a state lease sale in the bays and near land open waters. This was followed by drilling off wooden piers with a considerable amount of coring from barges.
In 1955 California passed the Cunningham-Shell Act allowing oil and gas production offshore in state waters.
Prior to this coring was allowed: however, no drilling could be done through hydrocarbon formations.
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Classes of offshore rigs
2 classes
Bottom Supported
Floating
Bottom Moored
Dynamically Positioned
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Bottom Supported Rigs
Submersibles
Barge design
Column design
Jack-ups
Mat supported
Independent leg
Slot type
Cantilever type
Platforms
Steel jacket
Gravity structure
Hybrid pliant tower
Tension leg platform
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Floating Rigs
Bottom Moored
Drilling tender
Drilling barge
Drill ship
Conventionally moored
Turret moored
Semi-submersible
Spar/Truss
Dynamically Positioned
Drill ship
Semi-submersible
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Submersible: Barge
6m water
Sits on bottom
Used in still waters (not rivers)
Derrick can be levelled
Deck may sit o