Underground Annular Blowout Preventer Spline Torque Transfer
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Solution Overview
Problem
Current underground blowout preventers used in oil and gas well drilling are complex, costly, and have low reliability due to issues like broken springs and shearing pins, leading to potential accidents and limited reusability, especially when dealing with high-pressure oil and gas layers.
Innovation Solution
An underground annular blowout preventer with a spline pair for torque transfer, check valves for fluid control, and a spring ejector system that allows for quick sealing and unsealing without removing the drill pipe, ensuring reliable operation and extended service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional well head blowout preventer is used with manual operation, then operator experience and responsibility are required for timely detection, but the response time is delayed and more bottom fluid enters the well
Solution Approach 1:
The patent installs an underground annular blowout preventer within the drill pipe that can automatically seal the annulus upon detecting well kick conditions. This preliminary positioning of the sealing mechanism underground enables immediate response without waiting for surface operator action, thus reducing the time loss while maintaining high reliability through automated detection and response systems.
2Productivity
If spring ejector system is used for sealing mechanism, then quick sealing and unsealing is achieved, but spring breakage may occur under high pressure difference
Solution Approach 1:
The patent designs the spring ejector system with pre-calculated pressure thresholds and incorporates relief mechanisms that activate before the spring reaches its breaking point. The system includes pressure-sensitive bypass channels that open alternative flow paths when pressure differential approaches critical levels, thus cushioning the spring from excessive stress while maintaining rapid sealing capability during normal operation.
3Object-generated harmful factors
If check valve is installed near the drill to seal inner side of drill pipe, then fluid reflux is prevented, but the check valve may fail to seal completely under high pressure
Solution Approach 1:
The patent combines the check valve function with the underground annular blowout preventer system. The check valve near the drill seals the inner side of the drill pipe while the underground preventer simultaneously seals the annulus. This merging of sealing functions creates a dual-barrier system where if one sealing mechanism partially fails, the other compensates, thus preventing fluid reflux reliably under high pressure conditions.
4Reliability
If traditional well killing operation with heavy mud is performed after well shut-in, then blowout is controlled, but the process is time-consuming and increases annular pressure difference
Solution Approach 1:
The underground annular blowout preventer performs preliminary sealing of the annulus immediately upon detecting well kick, establishing a closed system before heavy mud needs to be pumped in. This preliminary action creates a contained environment that accelerates the well killing process by preventing additional fluid influx during the transition to heavy mud circulation, thus reducing both time loss and annular pressure difference buildup.
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 solution provides a simple, reliable, and cost-effective means to prevent blowouts by allowing multiple sealing and unsealing operations without removing the preventer, reducing equipment costs and enhancing safety during well drilling.
Implementation Method 1
The upper joint and the lower joint are matched through a spline, so the torque can be transferred between the upper and lower drill pipe
Implementation Method 2
A rubber barrel is sleeved outside of the upper joint, so the rubber barrel can be extruded and expanded by the upper joint and the lower joint
Implementation Method 3
A spring ejector is set on the inner side of the upper end of the upper joint
Data Source
AI summary
An underground annular blowout preventer, which belongs to the technical field of underground blowout prevention, includes an upper joint and a lower joint are sleeved outside a central barrel. The lower end of the central barrel is fixedly connected with the lower joint. The lower end of the upper joint is sleeved on the inner side of the upper end of the lower joint. The upper joint is matched with the lower joint through a spline. The lower end of the upper joint can freely move relative to the lower joint along a spline pair. At least one rubber barrel is sleeved on the outer side of the upper joint. The rubber barrel can be extruded and expanded by the upper joint and the lower joint. The underground annular blowout preventer of the present invention can transmit large torque, has a simple structure, long service life, is convenient to use, and can be repeatedly used. The underground annular blowout preventer is used in coordination with a check valve of a near drill in the well drilling process, so that quick sealing of a well can be ensured, and well blowout accidents can be effectively prevented. A pipe column is lowered to seal the well and is lifted to open the well, and the inside of the drill rod is in communication with an annular space after the well is sealed, which facilitates replacement for heavy mud lubrication operations.