Wellbore Milling and Suction Apparatus for Underbalanced Clearing
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Solution Overview
Problem
Current methods for clearing wellbores using ball-type frac liner systems are inefficient, leading to formation damage, increased costs, and unsafe working conditions due to over-balanced pressure and loss of work-over fluids, which restricts well productivity and recoverable reserves.
Innovation Solution
A method and apparatus that combines milling and suctioning within the wellbore using a spoolable coiled tubing system with a venturi component or mechanical pump to create an underbalanced pressure environment, allowing for the removal of obstructions and cuttings while maintaining a closed-loop fluid recovery system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional coiled tubing with water nitrogen mixtures and mud motors is used to mill seats, then the diameter of the liner can be increased by removing balls and seats, but an over-balanced effect occurs with increased hydrostatic pressure greater than reservoir formation, leading to loss of work-over fluids and formation damage
Solution Approach 1:
The patent inverts the conventional over-balanced approach by using under-balanced pressure systems. Instead of injecting high-pressure fluids to remove obstructions, the system uses suction to remove milled materials while maintaining reservoir pressure greater than wellbore pressure, preventing formation damage and fluid loss
Solution Approach 2:
The patent employs hydraulic suction systems and pneumatic control mechanisms to create and maintain under-balanced pressure conditions. The hydraulic system provides controlled suction to remove cuttings without creating excessive hydrostatic pressure that would damage the formation
2Speed
If high velocity fluid/gas mixture is used to maintain flow, then the flow velocity can be maintained, but the surface iron (coiled tubing reel) and flow back vessel manifolds and connections are washed out
Solution Approach 1:
The patent converts the harmful high-velocity erosive flow into a beneficial controlled suction flow. The suction system captures milled materials at controlled velocities that are sufficient for removal but low enough to prevent erosion of surface equipment, transforming the erosive energy into useful transport energy
3Ease of operation
If current milling technology is used to remove obstructions, then balls and seats can be removed from the liner, but milled materials and cuttings remain in the wellbore causing sanding-in and potential tool loss
Solution Approach 1:
The patent merges the milling operation with simultaneous suction removal into a single integrated process. The bottomhole assembly combines the mill with suction nozzles, allowing milled materials to be removed continuously during the milling operation, preventing sanding-in and ensuring tool retrieval
Solution Approach 2:
The patent ensures continuous removal of milled materials throughout the milling process. The suction system operates continuously to capture cuttings and proppant as they are generated, maintaining a clear wellbore and preventing accumulation that would cause sanding-in or tool entrapment
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 the clearance of wellbores with larger diameters, reduces formation damage, and enhances safety by maintaining underbalanced pressure, effectively removing obstructions and cuttings while recovering fluids, thus improving well productivity and reducing operational risks.
Implementation Method 1
a venturi component or mechanical pump to create an underbalanced pressure environment
Implementation Method 2
create an underbalanced pressure environment, allowing for the removal of obstructions and cuttings while maintaining a closed-loop fluid recovery system
Data Source
AI summary
Methods and apparatuses are provided for clearing a wellbore using a component for milling and a component for suctioning within a wellbore. Obstructions such as ball frac seats, bridge plugs, or formation material can be milled within a wellbore. As a result, larger, unrestricted, diameters can be obtained within the liner/wellbore. The cleared wellbore can allow for various remedial tools to be run into the liner/wellbore. In addition, the milled particles can be suctioned/vacuumed up and can be pumped/pushed to surface in an underbalanced fashion. In some embodiments, this can be achieved by incorporating a bottom-hole pump or a venturi component into the bottomhole assembly. The system can be deployed using a spoolable single or multi-conduit coiled tubing system and can be configured as a well intervention or work-over technology. In some embodiments, the clearing equipment can be temporary or mobile.