Offshore universal riser system
First Claim
1. A drilling method comprising:
- installing a first annular seal module within an internal flow passage extending longitudinally through a riser string, the first annular seal module being secured within the flow passage between opposite end connections of the riser string, and the first annular seal module including a first seal-receiving profile;
installing a second annular seal module within the flow passage, the second annular seal module being secured within the flow passage between opposite end connections of the riser string, and the second annular seal module including a second seal-receiving profile;
installing a first seal within the first annular seal module, while the first annular seal module remains in the flow passage;
installing a second seal within the second annular seal module, while the second annular seal module remains in the flow passage;
sealingly engaging a tubular string within the flow passage with the first and second seals;
retrieving the first seal from the first annular seal module while the first annular seal module remains in the flow passage; and
retrieving the second seal from the second annular seal module while the second annular seal module remains in the flow passage.
1 Assignment
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Accused Products
Abstract
An offshore universal riser system may include a valve module which selectively permits and prevents fluid flow through a flow passage extending longitudinally through a riser string. An anchoring device may releasably secure the valve module in the passage. A method of constructing a riser system may include the steps of installing the valve module in the passage, and installing at least one annular seal module in the passage. The annular seal module may prevent fluid flow through an annular space between the riser string and a tubular string positioned in the passage. Drilling methods may include injecting relatively low density fluid compositions into the annular space, and selectively varying a restriction to flow through a subsea choke in a drilling fluid return line. The riser string, including housings for the various modules and external control systems, may be dimensioned for installation through a rotary table.
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Citations
10 Claims
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1. A drilling method comprising:
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installing a first annular seal module within an internal flow passage extending longitudinally through a riser string, the first annular seal module being secured within the flow passage between opposite end connections of the riser string, and the first annular seal module including a first seal-receiving profile; installing a second annular seal module within the flow passage, the second annular seal module being secured within the flow passage between opposite end connections of the riser string, and the second annular seal module including a second seal-receiving profile; installing a first seal within the first annular seal module, while the first annular seal module remains in the flow passage; installing a second seal within the second annular seal module, while the second annular seal module remains in the flow passage; sealingly engaging a tubular string within the flow passage with the first and second seals; retrieving the first seal from the first annular seal module while the first annular seal module remains in the flow passage; and retrieving the second seal from the second annular seal module while the second annular seal module remains in the flow passage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification