Expandable Clad for Drilling Loss Circulation Mitigation
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Solution Overview
Problem
High-loss circulation zones in wellbore drilling result in uncontrolled fluid loss and increased drilling costs due to fluid absorption by the formation, where existing mitigation techniques are often ineffective.
Innovation Solution
A bottom hole assembly comprising a drill bit, an under reamer, and a radially expandable clad that widens the wellbore diameter at the high-loss zone and deploys a mechanical barrier to seal the area, preventing further fluid loss without requiring the drill string to be removed from the wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If drilling fluid is circulated to cool the drill bit and carry cuttings, then drilling operations can continue, but fluid is absorbed by the formation causing loss circulation
Solution Approach 1:
The wellbore is segmented into zones by deploying the expandable clad across the high-loss circulation zone. This divides the continuous drilling fluid circulation path into separate segments, allowing fluid to be contained in the lower segment while maintaining circulation in the upper segment, thus preventing total drilling operation interruption
Solution Approach 2:
The expandable clad acts as an intermediary mechanical barrier inserted into the wellbore at the high-loss circulation zone. This intermediary structure physically blocks the formation pores and fractures that cause fluid absorption, allowing drilling fluid to circulate without being absorbed by the formation
2Loss of substance
If existing mitigation techniques are used to address high-loss circulation zones, then some fluid loss may be reduced, but the techniques are often ineffective
Solution Approach 1:
The system changes the physical state and configuration of the wellbore by expanding the clad from a compact configuration to an expanded state that contacts the wellbore wall. This parameter change creates a reliable mechanical barrier that physically blocks fluid loss pathways, providing consistent and reliable mitigation effectiveness
Solution Approach 2:
The expandable clad is deployed in advance to seal the high-loss circulation zone before continuing drilling operations. This preliminary action prevents further fluid loss and establishes a reliable barrier that ensures effective mitigation before the problem escalates
3Loss of substance
If the drill string is removed from the wellbore to address the high-loss zone, then the zone can be treated, but drilling time increases
Solution Approach 1:
The drill string itself serves the dual function of both drilling and deploying the mitigation device. The expandable clad is attached to the drill string and deployed from within the wellbore without requiring string removal, allowing the drill string to service itself by addressing the high-loss zone while remaining in position
Solution Approach 2:
The expandable clad is nested within the drill string in a compact configuration during descent. Once positioned at the high-loss circulation zone, the clad is expanded outward to contact the wellbore wall while the drill string remains nested within the clad structure, allowing simultaneous presence of both components
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
The solution effectively limits uncontrolled fluid loss and reduces drilling time and costs by mechanically isolating the high-loss zone, allowing continuous drilling operations without removing the drill string, thus enhancing drilling efficiency and reducing fluid consumption.
Implementation Method 1
The expansion assembly can include a power spring attached to the mandrel. In response to the actuation of the expansion assembly, the power string can direct the mandrel toward the clad.
Data Source
AI summary
A drilling bottom hole assembly for loss circulation mitigation includes a drill bit configured to drill a wellbore in a formation. The drill bit is attached to a drill string. The wellbore includes a high-loss circulation zone into which drilling fluid is lost during drilling the wellbore. An under reamer is attached to the drill string upstring of the drill bit. The under reamer is downhole of the high-loss circulation zone. The under reamer, in response to actuation, is configured to widen a diameter of the high-loss circulation zone. An expansion assembly is connected to the under reamer. The expansion assembly surrounds the drill string upstring of the under reamer. The expansion assembly is configured to cover the high-loss circulation zone after the diameter of the high-loss circulation zone is widened by the under reamer.