Well Plugging Method Using Angled Flushing Tool
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current well plugging and abandonment methods, such as section milling, are time-consuming and costly, and generate hazardous metal shavings that require complex handling and disposal.
Innovation Solution
A method involving perforation, cleaning, and plugging of a well's longitudinal section using a flushing tool with angled outlets to direct a flushing fluid and fluidized plugging material, forming a pressure-isolating plug across the well's cross-section, which reduces the need for surface installations and minimizes hazardous material handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If section milling is used to establish a pressure-isolating barrier, then a robust cement barrier can be formed across the complete cross section of the well, but the operation becomes very time-consuming and costly
Solution Approach 1:
The invention extracts and removes the problematic metal casing section using a milling tool, then replaces it with cement slurry to form the pressure-isolating barrier. This selective removal and replacement approach creates a reliable barrier without requiring extensive milling operations, thereby reducing time and cost while maintaining barrier integrity.
Solution Approach 2:
The invention uses a bridge structure as an intermediary element that spans across the milled section during cement slurry placement. This bridge provides support and ensures complete cross-section coverage of the cement barrier, enabling reliable pressure isolation to be achieved more efficiently than traditional methods.
2Reliability
If section milling is used to remove a longitudinal section of casing, then a pressure-isolating cement barrier can be formed, but metal shavings (swarf) are generated that require complex handling and disposal
Solution Approach 1:
The invention converts the potentially harmful metal shavings generated during milling into a beneficial situation by immediately filling the milled section with cement slurry. The cement acts as a containment medium that captures and immobilizes the metal shavings, transforming them from a disposal hazard into part of the final pressure-isolating barrier structure.
Solution Approach 2:
The invention discards the metal casing section that has been milled away, but simultaneously recovers the space it occupied by filling it with cement slurry. This approach eliminates the need to handle and dispose of metal shavings separately, as they are incorporated into the cement barrier that provides the required pressure isolation.
3Reliability
If section milling is used to plug and abandon a well, then pressure isolation can be achieved, but surface installations are required to separate metal shavings from well fluids
Solution Approach 1:
The invention extracts and removes the metal casing section in a controlled manner, then immediately replaces it with cement slurry before the well fluids can mix with and transport metal shavings to the surface. This sequential extraction and replacement eliminates the need for complex surface separation installations.
Solution Approach 2:
The cement slurry acts as an intermediary material that fills the annular space between the milled casing and the wellbore wall. This intermediary cement barrier prevents metal shavings from mixing with well fluids and being transported to the surface, thereby eliminating the need for complex surface separation equipment.
4Reliability
If metal shavings are generated during section milling, then pressure isolation can be achieved, but the shavings become lodged in equipment such as blowout preventers, representing obstructions
Solution Approach 1:
The invention performs preliminary action by placing the cement slurry immediately after milling the casing section, before the metal shavings can travel up the wellbore and lodge in surface equipment such as blowout preventers. This timely placement of the cement barrier prevents equipment obstruction while achieving pressure isolation.
Solution Approach 2:
The invention converts the harmful effect of metal shavings that could lodge in equipment into a beneficial outcome by using the cement slurry to capture and immobilize the shavings in place. This transforms the shavings from a source of equipment obstruction into part of the pressure-isolating barrier structure.
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 method effectively cleans and isolates the well, saving time and cost by using a fluidized plugging material that forms a robust plug, reducing the need for extensive surface equipment and hazardous material handling.
Implementation Method 1
pumping a flushing fluid down through the tubular work string, out through at least one flushing outlet in the flushing tool, into the pipe string and further out into said annulus via the perforations in the pipe string, thereby cleaning both the pipe string and the annulus along said longitudinal section
Implementation Method 2
pumping a fluidized plugging material down through the tubular work string and into the pipe string at said longitudinal section; placing the fluidized plugging material in the pipe string along at least said longitudinal section, thereby also placing the fluidized plugging material in said annulus via the perforations in the pipe string
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of plugging and abandoning a well (1), comprising : (A) lowering a perforation tool (31) into a pipe string (5) onto a longitudinal section (LI); (B) with the perforation tool (31), forming perforations (51) along said longitudinal section (LI); (C) with a flushing tool (33) attached to a work string (3) and lowered onto said longitudinal section (LI), pumping a flushing fluid (35) through the work string (3), out through at least one flushing outlet (331) in the flushing tool (33), into the pipe string (5) and into said annulus (8) via the perforations (51), wherein an outlet axis (b) of said flushing outlet (331) is non-perpendicular to a longitudinal axis (a) of the flushing tool (33); (D) pumping a fluidized plugging material (37) through the work string (3) and into the pipe string (5) at said longitudinal section (LI); (E) placing the fluidized plugging material (37) in the pipe string (5) along at least said longitudinal section (LI), thereby also placing the fluidized plugging material (37) in said annulus (8) via the perforations (51); (F) pulling the work string (3) out of the well (1); and (G) abandoning the well (1).