Wellbore Obstruction Tool with External Biasing Spring
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Solution Overview
Problem
Current methods for clearing wellbore obstructions during casing operations, especially in horizontal wellbores, are inefficient and costly, often requiring rotation of the casing string, which can cause damage, and existing obstruction-clearing tools with biasing springs can interfere with drill-out operations due to the spring's location.
Innovation Solution
A wellbore obstruction-clearing tool with a biasing spring positioned externally about an axially reciprocating and rotatable sleeve, separating it from the drill string, and a helical drive arrangement between the mandrel and sleeve for axial and rotational movement, allowing for obstruction clearance without rotating the casing string and facilitating drill-out by avoiding spring engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a biasing spring is positioned internally within the obstruction-clearing tool, then the tool can effectively clear obstructions through reciprocating motion, but the spring interferes with drill-out operations when the tool is cemented in the wellbore
Solution Approach 1:
The biasing spring is extracted from the internal components and repositioned to an external location on the tool assembly. Specifically, the spring is positioned on the outer surface of the rotating sleeve, away from the central drill string path. This extraction resolves the interference problem during drill-out operations while preserving the spring's function in driving the reciprocating motion for obstruction clearing.
Solution Approach 2:
The spring is relocated from the axial dimension (internal to the tool) to the radial dimension (external to the tool). By positioning the spring on the outer surface of the rotating sleeve rather than within the central bore, the design utilizes the radial space to accommodate the spring without compromising the axial drill-out path. This dimensional transition allows both obstruction clearing and drill-out operations to proceed without interference.
2Ease of operation
If the casing string is rotated to move past obstructions, then the casing can be advanced through tight spots, but high torque damages threads between casing joints and causes centralizers to drag
Solution Approach 1:
The tool is segmented into distinct functional components: a non-rotating casing string and a rotating sleeve assembly. The helical drive mechanism transfers rotational motion from the reciprocating casing to the sleeve, separating the rotation function from the casing string itself. This segmentation allows the casing to reciprocate without rotating, protecting threads and centralizers, while the sleeve performs the necessary rotation to clear obstructions.
Solution Approach 2:
The rotating sleeve acts as an intermediary between the non-rotating casing string and the obstruction-clearing function. The sleeve receives reciprocating motion from the casing through the helical drive and converts it to rotational motion at its distal end. This intermediary mechanism enables obstruction clearing through rotation without requiring the casing string itself to rotate, thereby avoiding thread damage and centralizer drag.
3Productivity
If a mud motor or jetting tool is attached to the bottom of the casing string to clear obstructions, then the obstruction can be removed, but the apparatus is not retrievable and adds significantly to the cost
Solution Approach 1:
The tool combines multiple functions into a single integrated assembly: the rotating sleeve with disruptor elements performs obstruction clearing, while the entire tool maintains drillability for future wellbore extension. The disruptor elements on the sleeve can cut or break obstructions, and the tool can subsequently be drilled out if needed, providing both clearing and retrievability capabilities in one device rather than requiring separate specialized tools.
Solution Approach 2:
The material properties of the tool components are selected to enable both obstruction clearing and drill-out operations. The rotating sleeve and disruptor elements are made of materials that are effective for cutting obstructions but can subsequently be removed by drilling. This parameter change in material selection allows the tool to transition from a clearing function to a retrievable state, avoiding the need for permanent, non-retrievable apparatus.
4Ease of operation
If teeth are provided on the bottom of the casing string to cut obstructions, then the casing can advance through obstructions, but the casing must be reciprocated or rotated which increases complexity
Solution Approach 1:
The helical drive mechanism enables the rotating sleeve to perform self-service rotation during the reciprocating motion of the casing. As the casing moves axially back and forth, the helical engagement between the drive mechanism and the sleeve automatically converts this linear motion into rotational motion of the sleeve. This self-service conversion eliminates the need for separate rotation actuators or complex control systems, reducing overall device complexity while maintaining effective obstruction cutting.
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 tool effectively clears obstructions in horizontal wellbores without rotating the casing string, reducing operational costs and minimizing interference during drill-out operations by keeping the spring out of the drill string's path, thus enhancing the efficiency and cost-effectiveness of wellbore extension.
Implementation Method 1
a helical drive arrangement between the mandrel and sleeve for driving the rotatable sleeve axially and rotationally along the mandrel during the downstroke and the upstroke of the mandrel
Implementation Method 2
a spring fit concentrically about an external surface of the rotatable sleeve and operatively connected between a distal end of the non-rotatable sleeve and the distal end of the rotatable sleeve, wherein the non-rotatable sleeve, in the retracted position, for energizing the spring
Data Source
AI summary
Embodiments of a reciprocating tool, used to engage and clear obstructions in a wellbore, have a biasing spring located externally about an axially reciprocating and rotatable sleeve to act between the rotatable sleeve and the non-rotatable mandrel to bias the rotatable sleeve to an extended position. During a drill out operation, a non-rotatable sleeve, connected to the mandrel for telescoping over the mandrel and the rotatable sleeve during a downstroke of the mandrel, guides a drill string for drill-out of at least the mandrel and other internal components. Positioning the biasing spring external to the rotating sleeve and downhole of the non-rotating sleeve prevents engaging the spring with the drill string. The rotating sleeve provides an internal guide for the drill out string to further avoid engagement with the spring.