Off-Bottom Flow Diverter Subassembly for Drilling Fluid Control
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Solution Overview
Problem
Current drilling technologies face issues with fluid flow control, particularly when transitioning between 'on-bottom' and 'off-bottom' conditions, leading to equipment damage, inefficient drilling, and slow response to formation fluid influx due to reliance on extreme pressures or mechanical interventions.
Innovation Solution
The off-bottom flow diverter subassembly, comprising a shank and fronthead with sliding components that open and close diverting flow passages, automatically adjusts drilling fluid flow based on drilling pressure, diverting fluid away from the bit during non-drilling conditions to prevent damage and maintain efficient drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rupture disc or shear pin is used to open alternative flow passages, then formation fluid influx can be controlled, but the system requires extreme pressures or mechanical interventions and must be replaced after use
Solution Approach 1:
The flow diverter subassembly automatically responds to formation fluid influx by allowing the drill string to lift off bottom, which opens the diverting flow passage without requiring external intervention, extreme pressures, or mechanical breakage. The system serves itself by using the natural lifting motion to trigger the flow diversion.
Solution Approach 2:
The flow diverter subassembly transitions from a static flow control system to a dynamic one where the diverting flow passage is automatically opened or closed based on whether the drill string is in contact with the bottom. This dynamic response eliminates the need for rupture discs or shear pins that require extreme pressures or mechanical interventions.
2Reliability
If the drill string is lifted off bottom to open flow passages, then formation fluid influx can be controlled, but the response time is slow
Solution Approach 1:
The flow diverter subassembly is pre-configured with the diverting flow passage that can be quickly opened by lifting the drill string off bottom. This preliminary setup allows for rapid response to formation fluid influx without requiring complex mechanical interventions or waiting for extreme pressure conditions.
3Reliability
If drilling fluid flow rate is increased to prevent formation fluid influx, then influx control is improved, but equipment wear increases due to vacuum effect
Solution Approach 1:
The flow control system is segmented into two pathways: the primary drilling fluid flow through the bit and the secondary diverting flow passage. This segmentation allows formation fluid influx to be controlled through the diverting passage without increasing the overall flow rate, thereby avoiding the vacuum effect and associated equipment wear.
4Productivity
If a flow diverter subassembly is used to automatically control fluid flow, then drilling efficiency is maintained, but the device structure becomes more complex
Solution Approach 1:
The flow diverter subassembly acts as an intermediary device between the drill string and the formation. It automatically mediates fluid flow control by opening or closing the diverting passage based on drill string position, maintaining drilling efficiency without requiring complex external control systems or frequent mechanical interventions.
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 solution reduces equipment wear, maintains drilling efficiency by controlling fluid flow, and quickly responds to formation fluid influx without requiring extreme pressures or mechanical interventions, enhancing operational time and productivity.
Implementation Method 1
At least one diverting flow passage is between adjacent sliding surfaces of the shank and the fronthead. Sliding of the fronthead and the shank with respect to each other opens and closes the at least one diverting flow passage.
Data Source
AI summary
An off bottom flow diverter subassembly. A fronthead and shank each includes a central bore. One of the shank and the fronthead has an outer diameter configured to fit within the central bore of another of the fronthead and shank. The shank and fronthead are arranged to slide longitudinally with respect to each other and are limited from sliding out of contact with each other. At least one diverting flow passage is between adjacent sliding surfaces of the shank and fronthead. Sliding the fronthead and shank with respect to each other opens and closes the diverting flow passage. Application of a force, sufficient to open the diverting flow passage, to a drill string to which the subassembly is attached in a direction toward an opening of a hole being drilled causes the diverting flow passage to open and drilling fluid to flow out of the subassembly away from the bit.