Pre-welded Casing Head Support Unit for Well Integrity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing welding practices for casing head support units (CHSU) in oil and gas well operations often lack quality assurance, leading to weld failures and leaks between the conductor strings, resulting in well shut-ins and costly repairs.
Innovation Solution
A casing head support system (CHSS) with a tubular body CHSU, featuring a coaxial connection and internal load profile to support a conductor hanger, is designed to be pre-welded in a controlled environment, eliminating the need for on-site cutting and welding, and includes a conductor string extension joint and adapter sub to enhance load transfer and leak isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If welding is performed at the wellsite in the field, then the CHSU can be installed on-site, but the welding quality cannot be guaranteed due to unfavorable field conditions
Solution Approach 1:
The CHSU is pre-welded to the conductor string extension joint in a controlled fabrication environment before field installation. This preliminary welding action ensures high-quality welds with proper quality assurance, eliminating the need for field welding while maintaining on-site installation capability through pre-assembled units.
2Productivity
If welding is performed without sufficient quality assurance and control, then the installation process is simpler and faster, but weld failures occur leading to leaks
Solution Approach 1:
All welding operations are performed in advance in controlled fabrication shops where quality assurance and quality control procedures can be properly implemented. The pre-welded CHSU units are then shipped to the wellsite for rapid installation, decoupling the welding quality assurance process from the installation timeline.
3Device complexity
If the CHSU is welded directly to the conductor at the wellsite, then the device complexity is reduced, but the load transfer and leak isolation effectiveness decrease
Solution Approach 1:
The system is segmented into distinct components: the CHSU, the conductor string extension joint, and the adapter sub. This segmentation allows for pre-welding of the CHSU to the extension joint in a controlled environment, ensuring proper load transfer pathways and leak isolation while maintaining overall structural efficiency.
Data Source
AI summary
A casing head support system (CHSS) for a casing head includes a casing head support unit (CHSU) having a tubular body with a support unit top end (SUTE) and a support unit bottom end (SUBE); a first conductor string extension joint coaxially fastened to the SUBE; and an internal load profile machined into an inner circumferential surface of the CHSU. The SUTE forms a coaxial connection with the casing head. The internal load profile supports a corresponding load shoulder on a conductor hanger. The CHSU contains a CHSU top preparation machined into the inner circumferential surface of the support unit. The CHSU top preparation is located at the SUTE. The CHSU top preparation mates with a corresponding casing head support unit running tool (CHRT) bottom preparation.