Patent ID: 6148922
Filing Date: 2000-11-21
Classification: E21B

Abstract:
A slide joint for a riser between a well and a petroleum installation having a platform, comprising:an outer pipe having an upper section and a lower section;an inner pipe, accommodated in the upper section of the outer pipe, the outer and inner pipes adapted to move telescopically relative to one another to compensate for changes in relative positions of the well and the platform;a first piston, the first piston being connected to a downward oriented end of the inner pipe, the first piston being responsive to actuation by hydraulic pressure to provide a tractive force on the riser;wherein a first annulus is formed between the inner pipe and the outer pipe, the first annulus being isolated from both a well fluid and a surrounding fluid, said first annulus above the first piston being subjected to hydraulic pressure;a protective sleeve, slidably disposed within lower section of the outer pipe below the first piston, the protective sleeve being pressure actuated to make contact with a lower end of the inner pipe, the protective sleeve being provided with an upper piston;wherein a second annulus is formed between the protective sleeve and the outer pipe, and the second annulus is subjected to a pressure when the protective sleeve is in contact with the lower end of the inner pipe, the pressure on the second annulus sealing the first piston against contact with the well fluid,the annular area of the upper piston toward the second annulus is greater than the annular area of the upper piston towards a third annulus on the opposite side of the upper piston, such that any leakage of fluid past the upper piston occurs in a direction from the second annulus to the third annulus on the opposite side of the upper piston.