Overlapping Stage Perforation for Uniform Proppant Distribution
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Solution Overview
Problem
Current well completion methods fail to uniformly distribute proppant material across perforation clusters, leading to imbalanced treatment where heel-ward clusters are often untreated due to erosion and uneven fluid distribution.
Innovation Solution
The method involves forming perforation clusters in stages that overlap, allowing for selective sealing and re-fracturing to ensure uniform proppant distribution by positioning plugs within previous stages to create new perforation clusters that overlap, thereby enlarging heel-ward clusters to match toe-ward cluster diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plugs are used to isolate stages during perforating and fracturing operations, then stage isolation is achieved, but the treatment becomes imbalanced with heel-ward clusters remaining untreated
Solution Approach 1:
The wellbore is divided into multiple stages separated by plugs, allowing independent treatment of each stage. The segmentation enables selective isolation and treatment of specific zones while maintaining the ability to address heel-ward clusters in subsequent operations.
Solution Approach 2:
Toe-ward clusters are treated first during the initial fracturing operation, establishing a foundation for subsequent treatment. The preliminary action of treating toe-ward clusters allows for later enlargement of heel-ward clusters to achieve uniform distribution.
2Ease of operation
If discrete non-overlapping stages are created, then sequential treatment is simplified, but heel-ward clusters receive insufficient treatment due to fluid distribution patterns
Solution Approach 1:
Toe-ward clusters are treated in a preliminary action during the first fracturing operation. This preliminary treatment establishes baseline conditions that allow subsequent operations to focus on enlarging heel-ward clusters, achieving uniformity while maintaining operational simplicity.
Solution Approach 2:
The treatment parameters are changed between operations: the first operation treats toe-ward clusters with initial parameters, while the second operation targets heel-ward clusters with modified parameters (fluid volume, pressure, proppant concentration) to achieve uniform distribution across all clusters.
3Adaptability or versatility
If multiple plugs are run in series to isolate multiple stages, then multi-stage treatment is enabled, but plug removal and reestablishment of flow becomes complex
Solution Approach 1:
Multiple plugs are used to segment the wellbore into discrete treatable stages. Each plug can be independently set and retrieved, enabling flexible multi-stage treatment while maintaining a systematic approach to plug management that simplifies the overall removal process.
Solution Approach 2:
Plugs are temporarily placed to enable treatment operations, then systematically retrieved after their isolating function is complete. The method establishes a pattern of setting plugs for treatment, completing treatment, and then retrieving plugs to reestablish flow, making the complexity manageable through systematic recovery procedures.
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 approach ensures a more uniform fracture network by enlarging heel-ward perforation clusters during the fracturing of subsequent stages, reducing heel-biased dominance and achieving a denser, more balanced fracture distribution.
Implementation Method 1
perforating the casing for the stage with a perforating gun assembly such that various channels are formed to connect the subterranean formations to the inside of the casing
Implementation Method 2
A fluid, e.g., water, water and sand, fracturing fluid, etc. may be pumped by a pumping system down the well
Implementation Method 3
fracturing the various channels associated with the stage
Implementation Method 4
pumping a given fluid through plural perforation clusters formed into a stage
Data Source
AI summary
A method for fracturing a well casing includes forming plural perforation clusters into a stage N associated with the well casing; fracturing the plural perforation clusters; forming a current stage N+1 by placing a plug within the stage N, to isolate a first subset of the plural perforation clusters from a second subset of the plural perforation clusters; and fracturing a second time the second subset, but not the first subset.