Dual Tubing String Adaptor for Wellhead
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Solution Overview
Problem
Current dual string well configurations with coil tubing face operational difficulties and high costs due to handling challenges, interference between strings, and lack of well control during service operations, leading to increased time and labor for maintenance.
Innovation Solution
A dual string adaptor for the wellhead apparatus that includes a main body with a production tubing hanger bowl offset non-concentrically and a coil tubing access port angled downwardly, allowing independent installation and removal of strings without interference, and enabling well control during operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coil tubing is installed in dual string wells, then flushing effectiveness is improved, but handling difficulty increases due to sharp radius bending requirements
Solution Approach 1:
The patent introduces a curved guide surface that provides a gradual bending path for the coil tubing, transitioning it from a straight configuration to a curved one along a controlled radius path. This dimensional guidance resolves the handling difficulty by providing a physical template for the correct bending geometry, eliminating the need for difficult manual bending while maintaining the flushing effectiveness of the coil tubing installation
2Adaptability or versatility
If existing dual string hangers are used, then production tubing can be hung, but service operations require removing both strings simultaneously increasing time and cost
Solution Approach 1:
The patent divides the wellhead hanging system into two independent segments: a production tubing hanger and a coil tubing hanger. Each hanger can be independently installed, removed, and serviced without affecting the other string. This segmentation allows service operations to be performed on one string while the other remains in place, dramatically reducing service time and eliminating the need for simultaneous removal of both strings
3Adaptability or versatility
If coil tubing and production tubing are installed in the same well casing, then dual production capability is achieved, but string entanglement occurs during service operations
Solution Approach 1:
The patent employs asymmetric positioning of the two tubing strings within the well casing. The production tubing is positioned on one side of the casing while the coil tubing is positioned on the opposite side, creating spatial separation. This asymmetric arrangement prevents the strings from interfering with each other during installation and service operations, eliminating entanglement issues while maintaining dual production capability
4Reliability
If kill fluids are used for well control during service operations, then well pressure is controlled, but gas circulation can lift kill fluid causing spills or blowouts
Solution Approach 1:
The patent introduces a well control valve as an intermediary device in the wellbore. This valve provides positive mechanical control of well pressure and flow, replacing the reliance on kill fluids for pressure management. By using the valve as an intermediary control mechanism, the system achieves reliable well pressure control without the hazards associated with kill fluid circulation and potential gas lifting
Data Source
AI summary
An apparatus for hanging a production string and a coil tubing within a well, the apparatus comprising: a main body with a lower end defining an annular mounting flange; a production string tubing hanger bowl in the interior open area configured for accommodating the production tubing string suspended therein, the production string tubing hanger bowl having a center axis non-concentrically positioned relative to the annular mounting flange; and a coil tubing access port extending from the outer surface of the main body to an inner opening, the coil tubing access port configured for accommodating the coil tubing passing therethrough and having an angular orientation downwardly and being on an angle off vertical and directed away from a center point of the annular mounting flange.