Wellhead Casing Rotation Assembly for Horizontal Well Cementing
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Solution Overview
Problem
The challenge of rotating a casing during cementing operations to ensure efficient displacement of cement slurry is hindered by the length and weight of the casing string, leading to restricted rotation and the need for multiple cement jobs due to formation pressure limitations, which complicates the process and increases costs.
Innovation Solution
A rotating tool system that utilizes a stroke tool to lift a seal assembly from the wellhead, allowing the proximal end to be rotated outside the wellhead, coupled with a downhole swivel, to facilitate rotation of the casing string, ensuring uniform cement dispersion and zonal isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the casing string is rotated during cementing operation, then cement displacement efficiency is improved, but the operation becomes impossible due to the length and weight of the casing string
Solution Approach 1:
The system divides the rotation function into two segments: a downhole swivel assembly that rotates with the casing string, and a separate rotating tool assembly that remains stationary at the surface. This segmentation allows the casing to rotate downhole without requiring rotation of the entire surface equipment, overcoming the limitation imposed by casing length and weight.
Solution Approach 2:
A rotating tool assembly acts as an intermediary device between the stationary surface equipment and the rotating casing string. This intermediary contains a swivel mechanism that allows the casing to rotate independently while maintaining connection to the stationary pump and control systems, enabling rotation without directly moving the entire casing string at the surface.
2Stability of the object's composition
If the casing string is rotated to evenly disperse cement, then cement uniformity is improved, but the operation becomes impossible due to formation pressure limitations
Solution Approach 1:
The rotation capability is segmented into a dedicated downhole swivel assembly that can rotate independently of the surface equipment. This allows the casing to be rotated for cement uniformity without requiring movement of the entire surface string, making rotation feasible even in pressure-sensitive formations.
Solution Approach 2:
The swivel assembly serves as an intermediary that enables rotation at the downhole level while maintaining a stationary connection at the surface. This intermediary mechanism allows cement to be evenly dispersed through rotation without the operational constraints that would prevent rotating the entire casing string from the surface.
3Reliability
If a second stage cement job is performed to prevent formation breakdown, then formation integrity is improved, but the process complexity increases
Solution Approach 1:
The system performs preliminary rotation of the casing string during the first cementing stage to ensure uniform cement dispersion and optimal placement. This preliminary action improves cement job effectiveness in the first stage, potentially reducing the need for a second stage cement job and thereby reducing overall process complexity while maintaining formation integrity.
Data Source
AI summary
Rotating a casing during a cementing operation to ensure efficient displacement of cement slurry. More specifically, embodiments are directed towards a sub and rotating tool that are positioned above a first cement operation, wherein the rotating tool is positioned in a kickoff point or build section of a horizontal well.