Cluster Opening Sleeves for Wellbore Zone Treatment
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Solution Overview
Problem
Current frac operations are limited by the number of balls that can be run in a single tubing string, restricting the versatility of zone treatment in staged frac operations, and require more flexible assemblies to accommodate varying formation and zone needs.
Innovation Solution
A cluster of sliding sleeves is deployed in the wellbore, where each sleeve has an inner insert that moves from a closed to an open condition upon engagement with a ball, allowing fluid communication and enabling multiple zones to be treated with a single-sized ball, with buttons in the ports maintaining pressure and eroding to facilitate fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sliding sleeves are deployed in the wellbore with different sized ball seats, then each zone can be treated in stages with different sized balls, but the number of balls that can be run in a single tubing string is limited
Solution Approach 1:
The wellbore treatment system is segmented into multiple zones, each with its own sliding sleeve and ball seat. Instead of using one large ball to open all sleeves, the system divides the function across multiple smaller balls of different sizes, where each ball is responsible for opening a specific zone's sleeve. This segmentation allows treatment of multiple zones without requiring a single oversized ball that would be limited by tubing string capacity.
Solution Approach 2:
The sliding sleeves are arranged in a nested configuration within the tubing string, with each sleeve containing a ball seat of a specific size. The sleeves are positioned sequentially along the wellbore, creating a nested structure where smaller balls can pass through upper sleeves to reach lower sleeves with larger seats. This nested arrangement enables multiple zones to be treated with multiple smaller balls rather than one large ball.
2Productivity
If a ball is seated in a sliding sleeve to open it, then fluid communication is established for zone treatment, but the ball prevents fluid from passing to lower zones
Solution Approach 1:
Each sliding sleeve is designed with a specific local function - a ball seat of a particular size matched to a specific zone. When a ball of the corresponding size is seated in a sleeve, it opens that specific zone for treatment while preventing fluid from passing to lower zones. This local quality assignment allows precise control over which zones receive treatment fluid, enabling efficient staged treatment while maintaining flexibility for different treatment scenarios.
3Device complexity
If single shot sliding sleeves are used that lock open once actuated, then the assembly is simpler, but the zones cannot be closed after opening
Solution Approach 1:
The sliding sleeves are designed as dynamic components that can transition between open and closed states. Each sleeve contains a ball seat that, when engaged by a ball of the appropriate size, shifts the sleeve from closed to open position. The sleeve can then be returned to the closed position by dropping another ball of the same or larger size. This dynamic capability allows zones to be opened and closed as needed, providing versatility for staged treatments and re-isolation without significantly increasing mechanical complexity.
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
This solution allows for the treatment of multiple zones using a single-sized ball, enhancing the versatility and efficiency of frac operations by enabling the deployment of various sleeve arrangements to suit specific formation needs, while maintaining sufficient pressure to open all sleeves in a cluster before treatment fluid dislodges the buttons.
Implementation Method 1
the erosion can wear away the button and may help break up the button to force it out of the port
Implementation Method 2
Keys or dogs of the insert's seat extend into the bore and engage the dropped ball, allowing the insert to be moved open with applied fluid pressure
Implementation Method 3
allowing the insert to be moved open with applied fluid pressure
Data Source
AI summary
A downhole sleeve has an insert movable in the sleeve's bore from a closed condition to an opened condition when a ball dropped in the bore engages an indexing seat in the sliding sleeve. In the closed condition, the insert prevents communication between the bore and the sleeve's port, while the insert in the opened condition permits communication between the bore and port. Keys of a seat extend into the bore to engage the ball and to move the insert open. After opening, the keys retract so the ball can pass through the sleeve to another cluster sleeve or to an isolation sleeve of an assembly. Insets or buttons disposed in the sleeve's port temporarily maintain fluid pressure in the sleeve's bore so that a cluster of sleeves can be opened before treatment fluid dislodges the button to treat the surrounding formation through the open port.