Underwater auxiliary wellhead aligning device and operating method

Abstract

The invention discloses an underwater auxiliary wellhead aligning device and an operating method. The underwater auxiliary wellhead aligning device comprises two sets of wellhead aligning structures which are symmetrically arranged, one edges of the two sets of the wellhead aligning structures are connected through a door shaft, and the other opposite edges of the two sets of the wellhead aligning structures are locked through a switch; the two sets of the wellhead aligning structures are in cylindrical shapes when the wellhead aligning structures are locked; each wellhead aligning structure comprises a semi-annular buffering steel plate, springs, a semi-circle-arc plate, a semi-circular-cylinder stressed plate, a semi-circular-ring base plate, a semi-circular-cylinder load bearing seat and a hoisting lug ring; the bottom face of the semi-circular-ring base plate is welded to the semi-circular-cylinder load bearing seat; the semi-circle-arc plate and the semi-circular-cylinder stressed plate are welded to the top face of the semi-circular-ring base plate; the semi-circle-arc plate, the semi-circular-cylinder stressed plate and the semi-annular buffering steel plate are connected through springs; the inner side face of the semi-annular buffering steel plate is an arc-shaped face; and the hoisting lug ring is arranged on the semi-circular-cylinder load bearing seat. According to the operating method, a second spud running casing can enter a low pressure wellhead safely and rapidly, and the influence on wellhead operation by the marine environment is reduced.

Description

technical field [0001] The invention relates to the field of drilling engineering for resources such as oil and natural gas, in particular to an underwater auxiliary wellhead alignment device and an operation method for safely entering an underwater low-pressure wellhead with an auxiliary casing for deep-water surface operations. Background technique [0002] The offshore deepwater drilling operation process is generally: surface jetting into the surface conduit (with low-pressure wellhead), second hole drilling, casing running, cementing, underwater blowout preventer and riser launching, and running operations, etc. Since the second casing operation is before installing the underwater blowout preventer and riser, when the casing is lowered to the low-pressure wellhead, affected by the ocean currents on the seabed, the casing is swaying, and the efficiency of the wellhead is extremely low. At the same time, the operation process The middle casing is very easy to collide with...

AI Technical Summary

Problems solved by technology

Since the second casing operation is before installing the underwater blowout preventer and riser, when the casing is lowered to the low-pressure wellhead, affected by the ocean currents on the seabed, the casing is swaying, and the efficiency of the wellhead is extremely low. At the same time, the operation process The middle casing is very easy to collide with the low-pressure wellhead, resulting in damage to the casing floating shoes, falling objects or damage to the seal of the low-pressure wellhead, which brings great safety risks to subsequent operations

[0003] Due to the relatively late development of marine deepwater operations in China, there is currently no corresponding auxiliary second-opening casing for low-pressure wellheads in China. Therefore, it is urgent to invent an auxiliary casing for underwater low-pressure wellheads.

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