Surge Immune Stage System for Wellbore Cementation
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Solution Overview
Problem
Current cementing methods for wellbore tubulars in deviated and subsea wellbores face challenges due to premature activation of hydraulically operated stage tools, which can lead to catastrophic consequences from pressure spikes, and are ineffective in weak formations, causing cement to flow into the formation rather than up the casing annulus.
Innovation Solution
A surge immune stage system that includes a deployment assembly with a plug release system, featuring opener and closer plugs and activators, a stage valve with specific components like a housing, sleeve, and seats, and a plug release mechanism to control cement flow into the annulus, preventing premature activation and ensuring effective cement placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hydraulically operated stage tool is used for subsea and deviated wellbores, then the stage collar can be opened, but premature activation occurs due to pressure spikes
Solution Approach 1:
The system performs preliminary actions by launching the opener plug and activator to the stage valve before cementing begins. The opener plug is positioned at the stage valve and the activator is ready to be pumped, ensuring the stage collar is opened at the precise moment needed rather than being prematurely activated by pressure spikes during cementing operations
Solution Approach 2:
The harmful effect of pressure spikes is isolated to a specific zone behind the cement slurry. The activator is pumped behind the cement slurry, creating a dedicated pressure zone that affects only the stage valve activation rather than the entire wellbore, thereby preventing premature activation elsewhere in the system
2Productivity
If cement is pumped into the annulus from the bottom of the casing, then cementing can be performed, but cement flows into weak formations instead of up the casing annulus
Solution Approach 1:
The stage collar is opened in advance by the opener plug before cementing begins. This preliminary opening ensures that the annulus path is established and ready to receive cement, preventing cement from seeking alternative paths into weak formations
Solution Approach 2:
The activator serves as an intermediary that transfers pressure selectively. It is pumped behind the cement slurry and translates pump pressure into stage valve opening force, while the cement slurry itself acts as an intermediary barrier that directs flow into the annulus rather than into weak formations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively manages pressure surges and ensures cement is accurately placed within the annulus, enhancing the stability and integrity of wellbore tubular cementation by preventing cement from flowing into weak formations, thus improving the isolation and production of hydrocarbons.
Implementation Method 1
Each of the plugs (63, 64, 65) may include a finned seal (63f, 64f, 65f)
Implementation Method 2
a latch sleeve, a lock sleeve for releasing the latch sleeve
Implementation Method 3
pumping the closer activator and plug to the open stage valve
Data Source
AI summary
A method for cementing a tubular string into a wellbore includes: running the tubular string into the wellbore using a workstring having a deployment assembly; delivering an opener activator through the workstring to the deployment assembly, thereby launching an opener plug from the deployment assembly; pumping the opener activator and plug to a stage valve of the tubular string, thereby opening the stage valve; pumping cement slurry into the workstring; pumping a closer activator through the workstring behind the cement slurry, thereby launching a closer plug from the deployment assembly; and pumping the closer activator and plug to the open stage valve, thereby driving the cement slurry into an annulus between the tubular string and the wellbore and closing the stage valve.