Pressure-Actuated Lead Impression Assembly for Single-Trip Wellhead Space-Out
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Solution Overview
Problem
Existing subsea hydrocarbon production systems require multiple trips to measure and adjust the wellhead space-out, which is time-consuming and inefficient, especially when using lead impression tools that need manual adjustment at the surface.
Innovation Solution
A lead impression system integrated with downhole tools that takes impressions during a single trip by utilizing a pressure differential to protrude and retract lead pads, eliminating the need for separate tools and manual surface adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a lead impression tool is used to measure wellhead space-out, then measurement capability is provided, but multiple trips and manual surface adjustments are required, increasing operational time
Solution Approach 1:
The patent combines the lead impression measurement function with the setting tool function into a single integrated device. The lead impression assembly is coupled to the setting tool, allowing both wellhead space-out measurement and tubing hanger setting operations to be performed during a single downhole trip, eliminating the need for separate measurement trips and manual surface adjustments.
Solution Approach 2:
The lead impression pads are pre-positioned on the lead impression assembly before deployment. When the tool reaches the downhole location, the impressions are taken automatically as part of the setting operation, performing the measurement action in advance during the same trip used for setting, rather than requiring a separate subsequent adjustment trip.
2Ease of operation
If manual surface adjustment is used to match wellhead space-out, then adjustment capability is provided, but the process requires retrieving the tool to surface and manually adjusting, reducing efficiency
Solution Approach 1:
The integrated lead impression assembly performs the measurement function automatically downhole without requiring surface intervention. The tool measures the wellhead space-out in-situ during the setting operation, and the data is available for immediate use in determining the correct load nut position, eliminating the need to retrieve the tool for manual measurement and calculation.
Solution Approach 2:
The patent replaces the manual mechanical adjustment process at the surface with an automated downhole measurement system. Instead of physically retrieving the tool, manually measuring, calculating, and re-setting, the system uses the integrated lead impression assembly to automatically capture the necessary measurements downhole, substituting manual operations with an automated mechanical system.
3Measurement precision
If separate lead impression tool and setting tool are used, then specialized measurement function is provided, but device complexity and number of trips increase
Solution Approach 1:
The patent merges the lead impression measurement function with the setting tool into a single integrated assembly. The lead impression assembly includes pads, a piston, and hydraulic components that are coupled to the setting tool, combining two previously separate functions (measurement and setting) into one device, thereby reducing the number of trips and tool changes required.
Solution Approach 2:
The integrated tool assembly performs multiple functions: it can take lead impressions for wellhead space-out measurement and also perform the tubing hanger setting operation. This multi-functional design eliminates the need for separate specialized tools for each function, reducing overall system complexity despite the added capabilities within the single assembly.
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
Enables efficient and accurate measurement of wellhead space-out during a single downhole operation, reducing operational time and enhancing the precision of tubing hanger locking in subsea environments.
Implementation Method 1
utilizing a pressure differential to protrude and retract lead pads
Data Source
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AI summary
A lead impression system having a downhole tool and a lead impression assembly assembled radially around the downhole tool is landed on a previously installed host casing hanger or a casing hanger being installed in the current/same trip to obtain a lead impression from the bore of the wellhead housing and indicate where the host casing hanger is located axially within the wellhead housing with respect to a feature on the bore of the wellhead housing from which the lead impression is obtained. Lead impression modules in the assembly have a lead pad that protrudes radially outward through a window on an outer sleeve according to a pressure differential between an internal and an external pressure of the lead impression assembly. The lead pad retracts to its pre-set position when the pressure differential exceeds a preset burst pressure.