Downhole Tool with Formation Weakening for Wellbore Enlargement
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Solution Overview
Problem
The existing wellbore enlargement process is hindered by the underreamer wearing down faster than the drill bit due to differences in formation hardness, as the underreamer encounters harder formations while being pulled through by the drill bit.
Innovation Solution
A downhole tool system that includes a formation weakening tool, which uses vibrational energy, electro pulses, or a laser beam to weaken the wellbore walls ahead of the underreamer, allowing the underreamer's cutter blocks to expand and increase the wellbore diameter more efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the underreamer is used to increase the wellbore diameter in harder formation, then the wellbore diameter can be increased, but the underreamer wears down faster than the drill bit
Solution Approach 1:
The formation weakening tool is deployed ahead of the underreamer to pre-weaken the formation by applying vibrational energy, electro pulses, or laser beams. This preliminary action reduces the hardness of the formation ahead of the underreamer, allowing the underreamer to operate in softened material and thereby reducing wear while maintaining enlargement productivity
Solution Approach 2:
The formation weakening tool acts as an intermediary between the drill bit and the underreamer. It modifies the formation properties in the zone between these two tools, creating a transition zone with reduced hardness that protects the underreamer from direct contact with hard formation, thus extending its service life
2Speed
If the drill bit drills at high speed through softer formation, then the drilling rate is high, but the underreamer positioned above experiences faster wear due to harder formation
Solution Approach 1:
The formation weakening tool performs preliminary treatment on the formation ahead of the underreamer, uniformly softening the material in advance. This eliminates the harmful effect of formation hardness variation by ensuring that even if the drill bit encounters soft formation, the underreamer will encounter pre-weakened formation of consistent, reduced hardness
Solution Approach 2:
The formation weakening tool changes the physical parameters of the formation (hardness, strength) in the zone ahead of the underreamer. By applying vibrational energy, electro pulses, or laser beams, the tool modifies the formation properties to create a more uniform, softer zone that allows the underreamer to operate at optimal conditions regardless of the original formation variability
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 enables the underreamer to effectively enlarge the wellbore diameter by weakening the formation walls, reducing wear and maintaining a consistent drilling rate across varying formation hardness layers.
Implementation Method 1
The formation weakening tool weakens a portion of the subterranean formation positioned radially-outward therefrom using vibrational energy
Implementation Method 2
The formation weakening tool weakens a portion of the subterranean formation positioned radially-outward therefrom using vibrational energy, electro pulses
Implementation Method 3
The formation weakening tool weakens a portion of the subterranean formation positioned radially-outward therefrom using vibrational energy, electro pulses, or a laser beam
Data Source
AI summary
A downhole tool for increasing a diameter of a wellbore disposed within a subterranean formation. The downhole tool includes an underreamer having a plurality of cutter blocks moveably coupled thereto that move radially-outward from a refracted state to an expanded state. The cutter blocks cut the subterranean formation to increase the diameter of the wellbore from a first diameter to a second diameter when in the expanded state. A formation weakening tool may be coupled to the underreamer. The formation weakening tool weakens a portion of the subterranean formation positioned radially-outward therefrom.