Downhole Cross Flow Prevention During Well and Power Shutdown

Abstract

A system and method for automatically preventing cross flow in a subterranean well during a shutdown event includes a plurality of downhole control valves located within the subterranean well. An energy storage device releases a stored energy during a shutdown event. A primary fail device is a normally close, fail open device that moves to a primary open position during a shutdown event, providing a portion of the stored energy to each of the plurality of downhole control valves during a shutdown event. The portion of the stored energy delivered to each of the plurality of downhole control valves is sufficient to move each of the plurality of downhole control valves to a valve closed position.

Description

BACKGROUND OF THE DISCLOSURE[0001]1. Field of the Disclosure[0002]The present disclosure relates in general to the control of subterranean wells, and more particularly to automatically preventing downhole cross-flow of fluids in subterranean multizone intelligent completion wells.[0003]2. Description of the Related Art[0004]The production of oil and gas in multilateral or multizone wells typically requires the use of various valves and other downhole equipment commonly known as intelligent completions. For example, an inflow control valve (ICV) assembly can be inserted into the well bore, and can include an inflow valve 28 that regulates the flow of fluid through the bore. The communication of commands from an operator at the surface to such valves and other downhole equipment is important to production control of the well.[0005]In some current multizone intelligent wells with inflow from multiple zones, only the surface valves and subsurface safety valves are closed during well shu...

AI Technical Summary

Benefits of technology

The patent describes a method for controlling the flow of fluids in a subterranean well. It includes the use of downhole control valves and a surface accumulator, primary fail device, and secondary fail device. These devices can be located at the surface of the well or belowground. The control valves can be associated with separate zones in the well, and when closed, they restrict the flow of fluids into and out of those zones. The accumulator stores energy, the primary fail device ensures that the system fails if, for example, there is a sudden power loss, and the secondary fail device prevents trapped pressure control fluid from exiting the control valves when they are in the closed position. The technical effects of this method include improved well control and safety during drilling and wellbore construction.

Problems solved by technology

The downhole control valves do not have a mechanism to automatically close and some current auto-close features available for such valves are subject to potential failures.

In addition, adding automatic features downhole can be difficult to install, service, and replace.

This crossflow could affect reserves management and ultimately reduce overall recovery from the well.

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