Straddle Tool Cement Placement in Annular Space
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Solution Overview
Problem
Existing methods for placing cement in annular spaces around tubular strings are inefficient, particularly when multiple barriers are needed, as they require multiple trips, are limited in deviated boreholes, or rely on complex mechanisms like ball delivery and swelling packers, which can reduce production flow.
Innovation Solution
A straddle tool that sequentially engages profiles on the tubular string to deliver cement into the annular space without perforation, using prepositioned communication valves and locking dogs to secure the tool in place, allowing for single-trip placement of cement rings that set up as barriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple barriers are placed at spaced locations using conventional packers, then zonal isolation is achieved, but operational complexity and time increase due to multiple trips or complex mechanisms
Solution Approach 1:
The tubular string is divided into multiple sections with prepositioned communication valves at spaced locations, allowing the cementing operation to be segmented into discrete zones. Each valve assembly acts as an independent segment that can be accessed sequentially by the straddle tool, enabling multiple barriers to be placed without requiring multiple trips or complex repackaging of the tubular string.
Solution Approach 2:
Communication valves and locating profiles are prepositioned on the tubular string before deployment. This preliminary action eliminates the need for complex real-time positioning mechanisms during the cementing operation. The straddle tool simply needs to engage the pre-positioned profiles and valves sequentially, significantly reducing operational time and complexity while maintaining reliable zonal isolation.
2Reliability
If ball delivery mechanisms are used for hydraulically set packers, then barriers can be placed, but device complexity increases due to ball catchers and seat blowout requirements
Solution Approach 1:
The invention extracts and eliminates the complex ball delivery, ball catcher, and seat blowout mechanisms from the barrier placement system. Instead of using hydraulically set packers that require these auxiliary components, the system uses prepositioned communication valves that can be directly accessed by the straddle tool, simplifying the overall device while maintaining reliable barrier placement capability.
Solution Approach 2:
The communication valves are self-contained and self-actuating. When the straddle tool engages a valve assembly and delivers cement, the valve automatically opens to allow cement flow and then closes when pressure is removed. This self-service mechanism eliminates the need for external ball delivery systems, ball catchers, and seat blowout procedures, significantly reducing device complexity.
3Reliability
If conventional cementing methods are used, then cement can be placed in annular space, but precision and control are reduced requiring perforation and squeeze cementing
Solution Approach 1:
The invention replaces the complex mechanical system of perforation and squeeze cementing with a controlled pressure-driven system. The communication valves provide precise mechanical positioning and control, allowing cement to be delivered exactly where needed through the prepositioned valve assemblies. This substitution eliminates the need for perforation operations and squeeze cementing while achieving superior cement placement precision.
Solution Approach 2:
The communication valves act as intermediaries between the straddle tool and the annular space. These valves provide a controlled interface that directs cement flow precisely to the desired locations in the annular space, eliminating the need for uncontrolled perforation and squeeze operations. The valves mediate the cement delivery process, ensuring accurate positioning and controlled placement.
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, single-trip placement and setting of multiple cement barriers in the annular space, improving operational efficiency and maintaining production flow by eliminating the need for perforation and reducing the complexity of barrier placement.
Implementation Method 1
The cement is formulated to stay in position and set up
Data Source
AI summary
A method of providing cement isolators in an annular space about a tubular string in open hole uses a straddle tool that sequentially engages profiles in the tubular string so that prepositioned communication valves to the surrounding annulus can be straddled to force cement out through the straddle tool and into the annular space. The cement is formulated to stay in position and set up. Each valved opening in the string comes with an associated locating profile and another profile for a locking dog to secure the straddle tool in position for forced delivery from the tool and into the valve assembly for delivery into the open hole annulus where a sealing ring of cement will set up for isolation. The operation sequentially put in place as many barriers as there are valve assemblies to straddle and in a single trip generally working in an uphole direction.