Downhole Mill With Pressure-Actuated Piston for Anchor Fluid Isolation
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Solution Overview
Problem
Existing downhole tools with valves require significant clean fluid, leading to delays and cost overruns due to contamination and fouling of passageways in the drill string, particularly when setting anchors and packers associated with whipstocks.
Innovation Solution
A mill design incorporating a housing with a fluid bypass pathway, a chamber, and a piston that aligns and misaligns a fluid passageway in response to pump pressure, allowing for reduced fluid usage and preventing contamination by keeping clean fluid isolated until needed, with a rupture member to manage pressure and prevent overpressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional valves and passageways are used in the drill string, then anchoring and packing functions can be achieved, but significant quantities of clean fluid are required and contamination fouls the passageways
Solution Approach 1:
The drill string is segmented into separate functional zones: a contaminated fluid pathway for drilling operations and a clean fluid chamber for anchoring/packing operations. The mill housing contains a dedicated clean fluid chamber that is isolated from the contaminated drilling fluid pathway, allowing independent fluid management for each function.
Solution Approach 2:
The clean fluid requirement is extracted from the main drilling fluid system. Instead of requiring large quantities of clean fluid to flow through the entire drill string, the invention extracts and contains the necessary clean fluid in a localized chamber within the mill housing, separating the clean fluid need from the contaminated fluid pathway.
2Reliability
If traditional valves are used to control fluid flow, then anchoring and packing can be set, but passageways become fouled by contaminated fluid causing delays and cost overruns
Solution Approach 1:
The fluid pathways are segmented into contaminated and clean zones. The mill housing includes a dedicated clean fluid chamber that is physically separated from the contaminated drilling fluid pathway, preventing contamination of the anchoring/packing fluid passageways while maintaining reliable setting function.
Solution Approach 2:
A piston mechanism acts as an intermediary between the contaminated fluid pathway and the clean fluid chamber. The piston can be actuated to open or close the clean fluid chamber, controlling fluid flow to anchors and packers without exposing the clean fluid pathway to contaminated drilling fluid.
3Ease of operation
If clean fluid is provided continuously at the rig site, then valve operations can be performed, but operational efficiency decreases due to delays from fluid management
Solution Approach 1:
The clean fluid is pre-loaded into the chamber within the mill housing before the drilling operation begins. This preliminary action eliminates the need for continuous clean fluid supply during operations, allowing rapid actuation of anchors and packers without delays associated with fluid management at the rig site.
Solution Approach 2:
The mill housing with its integrated clean fluid chamber provides self-service functionality for anchoring and packing operations. The system carries its own clean fluid supply and can independently actuate anchors and packers without requiring external fluid management interventions, thereby improving operational efficiency and reducing downtime.
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 design reduces fluid requirements by up to 20:1, prevents contamination of anchors and packers, allows continuous pumping, and mitigates early deployment risks through controlled pressure management, enhancing operational efficiency and reducing downtime.
Implementation Method 1
the piston responsive to pump pressure to move toward the milling feature
Data Source
AI summary
A mill including a housing having a fluid bypass pathway, a milling feature at a longitudinal end of the housing, a chamber defined by the housing, and a piston disposed in communication with the chamber, the piston defining a fluid passageway initially aligned with the fluid bypass pathway, the piston responsive to pump pressure to move toward the milling feature, the movement misaligning the fluid passageway with the fluid bypass pathway.