Wellbore Obstruction-Clearing Tool for Casing Advancement
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Solution Overview
Problem
Current methods for clearing wellbore obstructions during casing operations, such as rotation and use of expensive mud motors, are inefficient and costly, especially in horizontal wellbores where rotation is difficult and often ineffective.
Innovation Solution
A wellbore obstruction-clearing tool fitted to the downhole end of a tubular string, featuring a tubular mandrel and a rotatable sleeve with a helical drive, allows for axial and rotational movement to break up obstructions without rotating the casing string, using fluid circulation to convey debris to the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If casing string is rotated to move past obstructions, then casing can advance through tight spots, but high torque damages threads between casing joints and causes centralizers to drag and ream into the wellbore
Solution Approach 1:
The casing string is segmented into modular joints with standardized threading. The obstruction-clearing tool is attached to the downhole end, separating the obstruction-clearing function from the casing string itself, allowing the casing to be advanced without rotating the entire string.
Solution Approach 2:
An obstruction-clearing tool serves as an intermediary device attached to the downhole end of the casing string. This tool performs the obstruction-clearing function while the casing string remains stationary, preventing torque transmission to the casing threads.
2Ease of manufacture
If washing technique is used to erode obstructions, then fluids can wash out debris, but repeated running in and tripping out of tubulars is time consuming and expensive
Solution Approach 1:
The obstruction-clearing tool with cutting elements is installed on the casing string before entering the wellbore. This preliminary preparation allows the tool to mechanically break up obstructions during the first run, preventing the need for repeated tripping and washing operations.
Solution Approach 2:
The invention merges the obstruction-clearing function with the casing running operation by attaching cutting elements to the downhole end of the casing string. This combination allows simultaneous casing installation and obstruction removal in a single operation.
3Ease of operation
If teeth are provided on the bottom of casing string to cut obstructions, then casing can advance through obstructions, but apparatus is not retrievable and adds significantly to cost
Solution Approach 1:
The obstruction-clearing tool with cutting elements is designed as a disposable or easily replaceable component attached to the downhole end of the casing string. After use, the tool remains in the wellbore or is easily removed, avoiding the need for expensive retrievable apparatus.
4Ease of operation
If casing string is reciprocated to assist with moving past obstructions, then casing can advance through tight spots, but rotation of casing is extremely difficult or impossible in horizontal wellbores
Solution Approach 1:
Instead of rotating the casing string to clear obstructions, the invention inverts the approach by attaching a cutting tool to the downhole end and advancing the casing vertically while the tool cuts horizontally through obstructions. This inversion makes the method applicable to both vertical and horizontal wellbores.
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 clearing of wellbore obstructions without the need for casing rotation, reducing torque-related damage and operational costs, and allowing for successful advancement of the casing string to target depth.
Implementation Method 1
A helical drive is positioned between the mandrel and the sleeve, permitting the sleeve to reciprocate axially along the mandrel and to rotate relative thereto. The sleeve is driven to extend or retract axially and to rotate relative to the mandrel through axial reciprocation of the tubulars and the mandrel in the wellbore
Implementation Method 2
At least the rotation of the sleeve engaging the wellbore obstructions causes the obstructions to break up or erode, forming debris therefrom which is conveyed to surface by fluids circulated downhole through the string and uphole to surface in an annulus between the tubulars and the wellbore
Implementation Method 3
The fluids can also aid in hydraulically extending the sleeve during the upstroke and fluidly eroding wellbore obstructions
Data Source
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AI summary
A wellbore obstruction-clearing tool connected to the bottom of a tubing string, such as casing, utilizes a sleeve which is axially and rotationally moveable in response to axial reciprocation of a tubing string to engage and clear obstructions in the wellbore. Fluid is discharged through the casing and the tool to engage the obstructions and to convey debris through the annulus to surface. Thus, the obstructions are cleared from the wellbore, permitting the casing to be advanced, without the need to rotate the casing.