Method and system for lubricating riser slip joint and containing seal leakage

1. A fluid containment system for a riser slip joint, comprising:

a fluid container sealingly engaged to a fixed part of the slip joint;

a movable part of the slip joint axially movably engaged with the fixed part;

an annular seal disposed between the fixed part and the movable part, a portion of the movable part extending from the annular seal and a portion of the fixed part disposed within the fluid container;

a body of fluid disposed in the fluid container having a level selected to submerge the annular seal and at least the portion of the movable part; and

means for maintaining the level of the body of fluid substantially constant.

2. The system of claim 1 wherein the means for maintaining comprises a pump disposed between an outlet of the fluid container and a fluid storage tank, a controller for operating the pump at a selected rate and a fluid level sensor for measuring a level of fluid, the controller configured to operate the pump to maintain the measured level substantially constant.

3. The system of claim 2 wherein the controller operates the pump automatically in response to measurements made by the fluid level sensor.

4. The system of claim 1 wherein the movable part comprises an inner pipe at least partially disposed within an outer pipe forming the fixed part.

5. The system of claim 1 wherein the fixed part is coupled to an upper end of a portion of a riser extending from the slip joint to a blowout preventer proximate a bottom of a body of water.

6. The system of claim 1 wherein the movable part extends from the slip joint to a floating drilling platform.

7. The system of claim 1 wherein the body of fluid comprises drilling fluid.