Downhole Casing Pulling Tool Hydraulic Anchor
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Solution Overview
Problem
Traditional methods for retrieving stuck casing in wells, such as pilot milling and hydraulically powered jars, are time-consuming, labor-intensive, and often ineffective, particularly when dealing with mud-stuck casing, and older systems lack the necessary strength to handle modern pull loads.
Innovation Solution
A downhole pulling tool with a mandrel, anchor, and puller mechanism, where the anchor is disposed on the mandrel and hydraulically actuated slips engage the casing, allowing for increased pulling forces and torque transmission through larger OD members, enabling effective retrieval of stuck components without damaging the well.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pilot milling is used to remove stuck casing, then the casing can be removed, but the process is very time consuming and labor intensive
Solution Approach 1:
The invention extracts the cutting/milling function entirely from the retrieval process. Instead of using pilot milling to remove casing, the tool directly grasps and pulls the stuck casing using a basket grapple mechanism, eliminating the time-consuming milling step while maintaining reliable removal capability
Solution Approach 2:
The invention replaces the mechanical milling system with a hydraulic pulling system. The hydraulic piston generates direct pulling force on the stuck casing through the grapple, substituting the gradual mechanical removal process with a direct mechanical extraction process that is both faster and more efficient
2Force
If jars are used to generate retrieving force, then dislodging force can be applied, but the technique does not effectively retrieve mud stuck casing
Solution Approach 1:
The invention uses a hydraulic piston system to generate retrieving force instead of mechanical jars. The hydraulic system provides controlled, sustained pulling force that can effectively dislodge mud-stuck casing, overcoming the limitation of jar-based mechanical impact methods
Solution Approach 2:
The basket grapple mechanism provides universal engagement capability that works effectively with all types of stuck casing including mud-stuck casing. The grapple can grasp and pull various types of casing regardless of the sticking mechanism, making the tool universally effective where specialized jar techniques fail
3Force
If older anchoring systems are used, then anchoring can be achieved, but the pulling strength is much too weak to handle modern pull loads
Solution Approach 1:
The invention changes the key parameter of anchoring force generation by using a hydraulic piston system that can generate significantly higher forces than older mechanical anchoring systems. The hydraulic system allows for controlled application of high pulling loads that match modern casing weights and sticking forces
Solution Approach 2:
The tool combines multiple functional elements (hydraulic piston, basket grapple, anchor mechanism) into a composite system where each component contributes to the overall pulling strength. This composite design enables the tool to handle modern pull loads that exceed the capability of any single traditional component
4Volume of moving object
If the anchor section is disposed below the pull section, then the tool structure is compact, but the pulling load must pass through the anchor section causing wear and potential damage
Solution Approach 1:
The invention inverts the traditional arrangement by placing the anchor section above the pull section instead of below. This inversion allows the pulling load to be applied directly to the pull mechanism without passing through the anchor section, eliminating wear on the anchor while maintaining tool compactness through the inverted configuration
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 enables efficient retrieval of stuck casing by distributing high anchoring loads and providing sufficient pulling force, reducing the need for milling operations and minimizing equipment wear, while avoiding damage to the well components.
Implementation Method 1
The anchor piston is hydraulically movable from a first condition to a second condition. According, the anchor piston in the second condition can wedge the at least one slip against the portion of the mandrel
Implementation Method 2
The at least one puller piston supports the implement and is hydraulically movable relative to the mandrel from an extended condition to a pulled condition
Implementation Method 3
the at least one slip in the set condition can be wedged against a portion of the mandrel for engaging the anchor downhole in casing or tubing, for example
Data Source
AI summary
A pulling tool deploys on a workstring to retrieving a well component, such as casing or a liner, stuck downhole. The tool has an anchor, a puller, and an implement. The implement is supported on the end of the puller and engages the component. Hydraulic pressure supplied downhole moves at least one puller piston coupled to the implement along a piston mandrel to pull the implement and component. An anchor mandrel coupled to the workstring and the piston mandrel anchors the pulling tool downhole. The anchor has slips disposed on the anchor mandrel that engage in surrounding casing when an anchor piston disposed on the anchor mandrel is hydraulically actuated with the communicated pressure.