Segmented Mill Sleeve for Cement Plug Drilling
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Solution Overview
Problem
Current drilling practices require multiple trips and significant offshore rig time to drill through cement plugs in wellbores, necessitating the use of different drill bits and resulting in high financial costs due to lengthy procedures.
Innovation Solution
A tool assembly with a mandrel body and a disengageable mill sleeve that allows for fluid pressure-controlled decoupling and re-engagement, enabling the same drilling trip to remove cement from tubulars of differing diameters using a milling tool with abrasive ribs, and a mechanism for fluid circulation restoration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple drill bits are used to drill through cement plugs in wellbores, then the cement can be removed effectively, but the drilling process requires multiple trips and significant offshore rig time, resulting in high financial costs
Solution Approach 1:
The mill sleeve is divided into multiple segments that can be independently activated. Each segment contains abrasive ribs that can be engaged or disengaged from the wellbore wall independently, allowing the tool to drill through cement plugs of varying thicknesses and hardness in a single continuous trip, eliminating the need for multiple trips with different drill bits
Solution Approach 2:
The mill sleeve segments are designed to be dynamically adjustable during the drilling process. The segments can be rotated into and out of engagement with the wellbore wall, allowing the tool to adapt to different drilling conditions and maintain effective cement removal throughout the entire trip without requiring bit changes
2Adaptability or versatility
If different sized drill bits are required to drill through cement in tubulars of differing diameters, then the cement can be removed from both casing and liner sections, but the drill string must be pulled out and changed, resulting in extended operational time
Solution Approach 1:
The mill sleeve is designed with a universal structure that can function with tubulars of different diameters. The segmented design allows each segment to be independently positioned and engaged, enabling the same tool to effectively drill through cement in both larger casing sections and smaller liner sections without requiring changes to the drill string or tool configuration
Solution Approach 2:
Each segment of the mill sleeve can be independently configured with abrasive ribs tailored to the specific local conditions of the wellbore or liner section being drilled. This allows the tool to adapt its cutting characteristics to match the specific diameter and cement conditions of each tubular section, maintaining effectiveness across varying dimensions
3Device complexity
If fluid circulation is interrupted during cement drilling operations, then the drilling process can be simplified, but the ability to maintain continuous drilling and retrieve the tool efficiently is reduced
Solution Approach 1:
The mill sleeve segments are designed to allow fluid circulation to continue throughout the drilling process. The segmented structure creates channels that permit drilling fluid to flow through and around the segments, maintaining continuous cooling and debris removal while the abrasive ribs actively drill through the cement plug, thereby sustaining high productivity without interruption
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 removal of cement from both casing and liner sections during a single drilling trip, reducing rig time and costs by allowing continuous drilling with fluid circulation maintained, and facilitating the retrieval of the milling tool upon completion.
Implementation Method 1
a milling tool with abrasive ribs
Implementation Method 2
fluid pressure-controlled decoupling and re-engagement
Implementation Method 3
a drill bit to remove formation ahead of the drill bit
Data Source
AI summary
A tool assembly is described. In embodiments, the tool assembly has an elongated body having uphole and downhole ends adapted for forming a tool joint, where the body has an axial through bore and at least one aperture in a side wall of the elongated body for receiving a keying element, and an inner de-coupling sleeve movable within the through bore of the elongated body.