DRILLING RISER

• US 3,601,187 A
• Filed: 05/02/1969
• Issued: 08/24/1971
• Est. Priority Date: 05/02/1969
• Status: Expired due to Term

• Current Assignee: Danny R. Tidwell
• Original Assignee: Danny R. Tidwell
• Inventors: Tidwell, Danny R.
• Application Number:
  US04/821,173
• Time in Patent Office: 844 Days
• US Class Current: 175/7
• CPC Class Codes: E21B 17/01 Risers

Abstract

A marine riser, for use with floating drilling equipment, that has flexible joints attached to its upper and lower ends. The lower flexible joint connects the riser to a subsea wellhead. The upper joint links the riser to a vertically extensible joint which is in turn pivotally connected to the drilling vessel. A tensioning device aboard the vessel maintains the riser in tension, preventing it from buckling.

Claims

1. Apparatus for use in an offshore well operation comprising:

a. a substantially vertical riser;

b. an extensible joint attached to the upper end of the riser;

c. a flexible joint in said riser positioned below and in close proximity to the extensible joint;

d. means for flexibly connecting the lower end of the riser to a subsea wellhead;

e. means for pivotally connecting the extensible joint to a floating vessel; and

f. means for applying tension to the riser.

2. Apparatus as defined by claim 1 wherein the flexible joint is a ball joint.

3. Apparatus as defined in claim 2 wherein the means for flexibly connecting the lower end of the riser to the subsea wellhead includes a ball joint.

4. Apparatus for use in a well operation conducted from a floating vessel comprising:

a. a substantially vertical riser;

b. a first flexible joint attached to the lower end of the riser;

c. means for connecting the first flexible joint to a subsea wellhead;

d. a second flexible joint in said riser near the upper end thereof;

e. a slip joint attached to the upper end of the riser;

f. means for pivotally connecting the slip joint to the vessel;

g. means on the vessel for generating a tensile force; and

h. means for transmitting said tensile force to said riser.

5. Apparatus as defined by claim 4 wherein the second flexible joint is a ball joint.

6. Apparatus as defined by claim 5 wherein the first flexible joint is a ball joint.

7. Marine riser apparatus comprising:

a. a substantially vertical riser;

b. a first ball joint attached to the lower end of the riser;

c. means for connecting the ball joint to a subsea wellhead;

d. a second ball joint attached to the upper end of the riser;

e. a slip joint attached to the upper end of the second ball joint;

f. means for pivotally connecting the slip joint to a floating vessel; and

g. means for applying tension to the riser.