Depth-Activated Downhole Bend Assemblies for In-Situ Deflection
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Solution Overview
Problem
Existing downhole mud motors with adjustable deflection angles require retrieval to the surface for adjustments, which is time-consuming and inefficient for drilling deviated wellbores.
Innovation Solution
A downhole-adjustable bend adjustment assembly that allows in-situ adjustment of deflection angles and includes a locking mechanism to actuate automatically based on predefined depth and mud weight thresholds, enabling multiple configurations without surface retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the mud motor is retrieved to the surface for adjustment of deflection angle, then the deflection angle can be changed, but the drilling time is lost and productivity decreases
Solution Approach 1:
The bend adjustment assembly is designed to be self-adjusting downhole using the existing drilling fluid pressure and flow. The system uses the mud pressure differential created during drilling operations to automatically actuate the adjustment mechanism, eliminating the need for surface retrieval and manual adjustment.
Solution Approach 2:
The adjustment mechanism is actuated by drilling fluid pressure. A pressure differential valve responds to changes in mud pressure and flow rate, converting hydraulic pressure into mechanical motion that drives the deflection angle adjustment, allowing in-situ modification without bringing the motor to surface.
2Reliability
If the bend adjustment assembly is locked during drilling, then the deflection angle remains stable, but the ability to adjust is lost
Solution Approach 1:
The locking mechanism transitions from a static locked state to a dynamic adjustable state based on real-time drilling conditions. The pressure differential valve continuously monitors mud pressure and flow rate, automatically unlocking the mechanism when adjustment conditions are met, allowing the system to adapt between stability and adjustability as needed.
Solution Approach 2:
The pressure differential valve provides continuous feedback on drilling fluid pressure and flow rate conditions. This feedback controls the locking mechanism, unlocking it when pressure and flow indicate appropriate adjustment conditions, and re-locking when adjustment is complete, ensuring stable operation during actual drilling.
3Reliability
If the locking assembly is designed to prevent premature adjustment, then false actuation is avoided, but the complexity of the control mechanism increases
Solution Approach 1:
The pressure differential valve uses hydraulic principles to sense both mud pressure and flow rate simultaneously. By requiring a specific pressure differential condition to actuate, the system inherently prevents false triggering from normal pressure fluctuations, as both pressure and flow must be within specific ranges for adjustment to occur.
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 efficient and precise adjustment of deflection angles during drilling, reducing the time and effort required for changing the drill path, and enhancing the flexibility of directional drilling operations.
Implementation Method 1
the locking assembly comprises a rupture disk configured to burst at a predefined pressure
Implementation Method 2
a mud weight has reached a predefined mud weight threshold at a given depth, in response to which the locking assembly is configured to actuate from the locked configuration to an unlocked configuration
Data Source
AI summary
A downhole mud motor includes a driveshaft rotatably disposed in a driveshaft housing, a bearing mandrel coupled to the driveshaft, wherein the bend adjustment assembly includes a first configuration that provides a first deflection angle between the driveshaft housing and the bearing mandrel, wherein the bend adjustment assembly includes a second configuration that provides a second deflection angle between the driveshaft housing and the bearing mandrel, and a locking assembly including a locked configuration configured to lock the bend adjustment assembly into one of the first configuration and the second configuration until the downhole mud motor has at least one of reached a predefined depth in the wellbore, and a mud weight has reached a predefined mud weight threshold at a given depth, in response to which the locking assembly is configured to actuate from the locked configuration to an unlocked configuration.