Back-Reaming Downhole Tool for Deviated Wellbore Hole Cleaning
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Solution Overview
Problem
Existing drilling technologies face challenges with solids and debris accumulation in deviated wellbores, leading to stuck pipe, high friction, and inefficient hole cleaning, which results in rig downtime and tool failure.
Innovation Solution
A downhole tool with ports and reaming blades that eject rearward and forward jets of fluid, controlled by a surface unit, to weaken and remove cuttings beds during the pulling of the drill string, combined with back reaming to ensure a clean wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If drilling operations are conducted in deviated wellbores, then drilling depth and reach are improved, but solids and debris accumulate on the lower side wall causing stuck pipe and hole cleaning issues
Solution Approach 1:
The patent applies reverse reaming by rotating the reaming blades in counter-clockwise direction (opposite to conventional clockwise rotation) while pulling the drill string upward. This inversion of the reaming direction creates upward and outward forces that effectively lift and remove cuttings from the lower side wall of the wellbore, directly addressing the hole cleaning problem in deviated sections
Solution Approach 2:
The patent utilizes drilling fluid (mud) flow through the annulus and rearward jets ejected from ports to fluidize and transport cuttings. The hydraulic action of the drilling fluid combined with the mechanical action of reaming blades creates an effective hole cleaning system that prevents cuttings accumulation in deviated wellbores
2Reliability
If conventional reaming is used to clean the wellbore, then cuttings are removed, but the process is time-consuming and causes rig downtime
Solution Approach 1:
The patent performs back reaming during the pull-out of the drill string operation itself, rather than requiring a separate clean-out trip. The reaming blades are positioned on the tool and automatically engage the wellbore wall as the string is pulled upward, cleaning the hole during the necessary drilling operation and eliminating additional downtime
Solution Approach 2:
The patent enables continuous hole cleaning action during the entire pull-out operation. The reaming blades continuously contact and clean the wellbore wall as the tool moves upward, and the drilling fluid continuously flows to transport cuttings, maintaining uninterrupted cleaning action throughout the operation
3Productivity
If high friction occurs due to debris accumulation, then drilling progress slows down, but increasing drill string tension can force debris removal
Solution Approach 1:
The counter-clockwise rotation of reaming blades during pull-out creates upward lifting forces and outward radial forces that actively remove cuttings from the lower side wall, reducing friction and allowing the drill string to move freely without excessive tension, thereby maintaining drilling productivity
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 reduces the risk of pipe sticking and enhances drilling efficiency by ensuring a clean wellbore, minimizing downtime and tool wear.
Implementation Method 1
The plurality of first ports are configured to eject rearward jets of fluid in the open state
Implementation Method 2
back reaming the wellbore by reaming blades of the downhole tool
Data Source
AI summary
A downhole tool includes: a tubular body having a central bore; a plurality of first ports that extend through a sidewall of the tubular body; a plurality of reaming blades that extend from an outer surface of the sidewall; and a flow control node configured to control a switching of each of the plurality of first ports between an open state and a closed state based on a command from a surface control unit. The plurality of first ports are configured to eject rearward jets of fluid in the open state.