Subterranean Well Plugging via Perforation and Pressure Surge
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Solution Overview
Problem
Existing methods for plugging subterranean wells, such as petroleum wells, face challenges in efficiently and safely sealing the wellbore both inside and outside the casing, particularly in ensuring the annulus is clean and free of debris to allow for a reliable cement plug, which can be costly and time-consuming.
Innovation Solution
A method involving a perforating tool to create holes in the casing, a surge tool to lower pressure and flow fluids from the annulus, and pumping a fluidized plugging material into the well section, eliminating the need for circulating cleaning fluids by creating sufficient turbulence to remove debris and fluids, thereby simplifying the plugging process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a section of casing is removed to arrange a cement plug in the wellbore, then the wellbore can be sealed inside and outside the casing, but the device complexity and operational cost increase
Solution Approach 1:
The invention extracts and removes the problematic annular space between the casing and wellbore by creating holes through the casing wall, allowing the plugging material to be placed directly in the annulus without removing the casing itself. This achieves the sealing function while avoiding the complexity of casing removal operations.
Solution Approach 2:
The invention uses an intermediary approach by perforating the casing to create communication pathways between the wellbore and annulus, allowing plugging material to bridge through the casing wall and seal the annular space. This intermediary method avoids both casing removal and direct annular access.
2Reliability
If cleaning fluids are circulated to clean the annulus before plugging, then the annulus is free of debris for reliable cement plug, but the loss of time and operational cost increase
Solution Approach 1:
The invention extracts and removes the need for separate cleaning operations by integrating the cleaning function into the plugging operation itself. The high-velocity flow of plugging material through the perforations automatically cleans the annulus of debris and fluids, eliminating the need for prior cleaning fluid circulation.
Solution Approach 2:
The plugging material itself performs the cleaning function as it is pumped through the wellbore and into the annulus. The high-velocity flow of the plugging material automatically removes debris and contaminants from the annulus, allowing the system to self-clean without requiring separate cleaning operations.
3Reliability
If specialized equipment is used for plugging operations, then the wellbore can be safely plugged, but the operational cost increases
Solution Approach 1:
The invention makes existing wellbore equipment multi-functional by using the same tubing string and pumping equipment for both delivering plugging material and cleaning the annulus. The perforating tool serves both to create access pathways and to enable the plugging material to reach the annulus, reducing the need for specialized dedicated equipment.
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 allows for efficient and reliable sealing of the wellbore by creating a clean annulus environment for the cement plug, reducing operational costs and time by eliminating the need for additional cleaning fluids and enabling a single-trip operation for perforating and surging tools.
Implementation Method 1
operating the surge tool to lower the pressure inside the part of the casing located in the well section and flowing a well fluid from an annulus between the casing and a well formation through the holes
Implementation Method 2
pumping a fluidized plugging material into the well section via a tubing string
Data Source
AI summary
A method for plugging a subterranean well (6), comprising running a perforating tool (1) into the subterranean well and positioning the perforating tool in a well section (L) to be plugged; operating the perforating tool to create a plurality of holes (10) in a part (5) of a casing (4) located in the well section; running a surge tool (2) into the well; operating the surge tool (2) to lower the pressure inside the part (5) of the casing (4) located in the well section (L) and flowing a well fluid from an annulus (11) between the casing (4) and a well formation (7) through the holes (10); and pumping a fluidized plugging material into the well section (L) via a tubing string (9).