Vertical subsea tree assembly control

Abstract

A vertical subsea tree is operated by a subsea control module supplied with hydraulic and electric power from the surface through the vertical subsea tree. A landing sub is communicatively coupled to the surface with a landing sub umbilical and run to the vertical subsea tree. The landing sub engages mating penetrations on an upper portion of the master valve block of the vertical subsea tree to supply flow passages extending from the penetrations to the subsea control module through the master valve block. The subsea control module is then operated through the landing sub umbilical to control operation of the vertical subsea tree.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]This invention relates in general to control of a subsea well completion and, in particular, to a system and method for subsea well control by landing a landing sub on a vertical subsea tree.[0003]2. Brief Description of Related Art[0004]Subsea wellhead assemblies are typically used in the production of hydrocarbons extracted from subterranean formations below the seafloor. Subsea wellhead assemblies generally comprise a wellhead housing disposed at a wellbore opening, where the wellbore extends through one or more hydrocarbon producing formations. Casing and tubing hangers are landed within the housing for supporting casing and production tubing inserted into the wellbore. The casing lines the wellbore, thereby isolating the wellbore from the surrounding formation. Tubing typically lies concentric within the casing and provides a conduit for producing the hydrocarbons entrained within the formation. Wellhead assemblies...

AI Technical Summary

Benefits of technology

[0012]An advantage of a preferred embodiment is that it provides a means to operate a subsea vertical tree through a subsea control module using a single umbilical run from the surface with a landing sub. This eliminates the need for use of multiple umbilicals, one that runs separately with the landing sub for operation of the landing sub and one run directly to the subsea control module. In addition, the disclosed embodiments eliminate the need for additional backup umbilicals associated with the subsea control module umbilical. Still further, the disclosed embodiments eliminate the need to have ROVs unhook from other assemblies to install and disconnect a subsea control module umbilical. The disclosed embodiments also reduce the management requirements associated with umbilicals by reducing the total number of umbilicals needed in an intervention or workover operation, thereby reducing installation time and risk. All these factors contribute to a more efficient and safer system that has a reduced capital expenditure for use and a reduced operating expenditure due to the faster and more efficient installation method.

Problems solved by technology

In turn, this may cause the cost of such umbilicals to be incredibly steep, upwards of multi millions of dollars to construction an umbilical that is strong enough and long enough to be used at subsea locations exterior of a subsea riser.

These umbilicals may also be subject to spooling damage during operation.

When the umbilicals are damaged operating costs go up significantly as the umbilical must be retrieved, repaired and rerun.

Again, this can add significantly to the cost of the well operation as well as necessitate additional equipment to store the backup umbilical at the surface platform.

This can also add significantly to the costs of the operation of the well.

Running of multiple umbilicals for subsea operations adds significantly to the costs of operation as additional spools and equipment are needed at the surface to support the additional umbilicals.

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