Angled Drill Pipe Nozzle Assemblies for Borehole Cleaning
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Solution Overview
Problem
Inadequate borehole cleaning during subterranean well drilling leads to costly issues like well pack off, mechanical pipe sticking, and difficulties in logging and cementing, particularly in extended reach and deviated wells, due to reduced annular velocity and suspension capabilities of drilling fluids as they flow through nozzles in the drill bit.
Innovation Solution
The implementation of angled drill pipe nozzle assemblies that can transition between closed and open states, controlled by hydraulic pressure, to enhance fluid flow and annular velocity, allowing drilling fluid to be discharged into the annulus and assist in carrying cuttings to the surface, thereby improving borehole cleaning efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If drilling fluid flows through nozzles within the drill bit, then the drill bit is lubricated and cooled, but the drilling fluid loses much of its annular velocity and force, resulting in reduced sweeping and suspension capabilities
Solution Approach 1:
The system segments the fluid flow path by introducing intermediate nozzle assemblies at multiple locations along the drill string, separating the cooling function at the drill bit from the borehole cleaning function in the annulus. This allows fresh drilling fluid to be discharged into the annulus at multiple points to maintain annular velocity and suspension capabilities independent of the drill bit cooling flow.
Solution Approach 2:
The intermediate nozzle assemblies act as intermediaries that transfer fresh drilling fluid from the drill string interior to the annulus. These nozzles receive high-pressure fluid from the drill string and redirect it into the annulus to restore annular velocity and suspension capabilities without requiring the fluid to pass through the drill bit nozzles first.
2Productivity
If drilling fluid is circulated through the drill pipe to cool and lubricate the drill bit, then the drill bit operates efficiently, but borehole cleaning becomes sub-optimal due to reduced annular velocity
Solution Approach 1:
The system divides the drilling fluid circulation into separate functional zones: drill string interior for delivering fresh fluid, intermediate nozzle assemblies for transfer, and annulus for borehole cleaning. This segmentation allows simultaneous optimization of drill bit cooling and borehole cleaning without compromising either function.
Solution Approach 2:
Fresh drilling fluid is delivered to intermediate nozzle assemblies before reaching the drill bit, allowing the fluid to be discharged into the annulus at multiple points along the drill string. This preliminary discharge maintains annular velocity and suspension capabilities throughout the borehole length before the fluid reaches the drill bit for cooling and lubrication.
3Adaptability or versatility
If the drill string is extended into extended reach and deviated wells, then exploration capability is improved, but borehole cleaning becomes increasingly difficult due to reduced annular velocity
Solution Approach 1:
The drill string is segmented into multiple sections with intermediate nozzle assemblies distributed along its length. This segmentation enables fresh drilling fluid to be discharged into the annulus at multiple points, maintaining annular velocity throughout the entire well length, particularly in extended reach and deviated configurations where velocity maintenance is critical.
Solution Approach 2:
The system adds a radial dimension to fluid delivery by discharging fresh drilling fluid from the drill string interior into the annulus at multiple intermediate points, not just at the drill bit. This multi-point radial discharge creates multiple fluid injection zones along the wellbore, maintaining suspension capabilities in extended reach and deviated sections.
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 maintains efficient annular velocity and force along the borehole length, effectively suspending and removing cuttings, reducing drilling duration and costs, especially in challenging well types like extended reach and deviated wells.
Implementation Method 1
Each nozzle assembly is transitionable between a closed state and an open state. When in the closed state, drilling fluid within the interior of the drill string is prevented from passing through the flow path. When in the open state, drilling fluid traverses the flow path and is discharged into the annulus
Implementation Method 2
Efficient borehole cleaning requires effective transport of cuttings through the annular space and thus sufficient annular velocity and/or drilling fluid rheological qualities to suspend the cuttings within the drilling fluid for the entire length of the well
Implementation Method 3
The drilling fluid helps lubricate and cool the drill bit, but also serves to convey (carry) borehole 'cuttings' (e.g., rock debris, gravel, and other solid particulates) to the surface through an annulus defined between the exterior of the drill pipe and the wellbore wall
Data Source
AI summary
A drilling system includes a drill string extendable into a borehole from a drilling platform and conveying a drilling fluid to a drill bit arranged at a distal end of the drill string, an annulus defined between the drill string and an inner wall of the borehole and in which spent drilling fluid ejected from the drill bit flows back to the drilling platform, and a plurality of nozzle assemblies installed on the drill string, each nozzle assembly providing a fluid flow path between an interior of the drill string and the annulus. Each nozzle assembly is transitionable between a closed state, where the drilling fluid within the interior is prevented from passing through the fluid flow path, and an open state, where the drilling fluid traverses the fluid flow path and is discharged into the annulus to combine with the spent fluid.