Rotating Flow Control Device for Offshore Drilling Pressure Barriers
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Solution Overview
Problem
Conventional wellbore fluid control devices in both offshore and land-based drilling operations fail to provide a sufficient pressure barrier against sudden pressure increases and kicks, which can damage equipment, lead to spillage, and pose safety and environmental risks.
Innovation Solution
A rotating flow control device (RFCD) is installed on the head of wellbore fluid control devices, featuring a stationary housing, sealed bearing assembly, elastomeric stripper element, and a clamp for secure attachment, creating an additional pressure-resistant barrier between wellbore fluids and the external environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wellbore fluid control devices (riser diverter or blowout preventer) are used, then basic fluid containment is provided, but insufficient pressure barrier protection against kicks exists
Solution Approach 1:
The rotating flow control device is nested on top of the conventional wellbore fluid control device (riser diverter or blowout preventer). The RFCD housing sits within the central bore of the conventional device, creating a nested configuration where the inner device enhances pressure protection without replacing the outer device. This nesting approach provides an additional pressure barrier while utilizing the existing structural framework of the conventional device.
Solution Approach 2:
The wellbore fluid control system is segmented into two independent but cooperative components: the conventional control device (riser diverter or blowout preventer) and the rotating flow control device. Each segment performs its function independently, with the RFCD providing specialized pressure barrier protection through its elastomeric stripper element and sealed bearing assembly, while the conventional device provides basic fluid containment and diversion.
2Reliability
If an additional pressure barrier is added to enhance safety, then protection against kicks is improved, but device complexity increases
Solution Approach 1:
The rotating flow control device is designed to perform multiple functions within a single integrated structure. The elastomeric stripper element provides both sealing against wellbore fluids and containment of pressure kicks. The sealed bearing assembly simultaneously supports rotational movement of tubulars and maintains fluid tightness. The housing structure provides both mechanical support and pressure containment. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The elastomeric stripper element utilizes flexible elastomeric material to create an effective pressure barrier. The elastomeric nature allows the element to deform and conform to the tubulars passing through it while maintaining sealing integrity under pressure. This flexible shell approach provides reliable pressure containment without requiring complex rigid mechanical sealing systems.
3Reliability
If a sealed bearing assembly is used to support rotating tubulars, then fluid-tight rotation is achieved, but manufacturing complexity increases
Solution Approach 1:
The sealed bearing assembly utilizes hydraulic sealing principles to prevent wellbore fluids from penetrating into the bearing elements. The seal elements create fluid-tight barriers that allow rotational movement while maintaining pressure containment. This hydraulic sealing approach is a well-established manufacturing technique that balances sealing effectiveness with manufacturing feasibility.
Solution Approach 2:
The sealed bearing assembly acts as an intermediary component between the rotating tubulars and the stationary housing. It mediates the interaction by allowing rotational movement while blocking fluid passage. The bearing elements and seals work together as an intermediary system that reconciles the conflicting requirements of rotation and fluid tightness without requiring direct contact between moving and stationary parts.
4Ease of operation
If the RFCD is designed to be easily installed on conventional devices, then installation simplicity is improved, but structural robustness may be compromised
Solution Approach 1:
The RFCD is designed to be pre-assembled as a complete unit on the ground or in a controlled environment before being installed on the conventional wellbore fluid control device. The elastomeric stripper element, sealed bearing assembly, and housing are pre-configured and tested together. This preliminary assembly simplifies field installation while ensuring structural integrity, as the complex internal components are already properly positioned and secured before installation on the rig.
Solution Approach 2:
The rotating flow control device incorporates dynamic elements that adapt to installation conditions. The elastomeric stripper element can deform to accommodate slight misalignments or variations in the conventional device's central bore dimensions. The sealed bearing assembly allows for rotational adjustment during installation. This dynamic adaptability enables easy installation on different conventional devices while maintaining robust structural connection.
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 RFCD effectively prevents wellbore fluid spillage and venting by providing an additional pressure-resistant barrier, enhancing rig safety and environmental protection during drilling operations, even in the event of kicks or equipment failures.
Implementation Method 1
an elastomeric stripper element for sealing around tubulars
Implementation Method 2
a seal for sealing the bearing elements from wellbore fluids
Data Source
AI summary
The invention relates to a rotating flow control device and methods of using the same for controlling wellbore fluids at the head of a riser diverter for use in offshore drilling operations or the head of a blowout preventer stacks annular for conventional land-based drilling operations. The rotating flow control device comprises a stationary housing to be mounted on the head of a riser diverter or the blowout preventer stacks annular, an inner tubular shaft that permits the passage of a tubular, sealed bearing elements for supporting and permitting the axial rotation of the inner tubular shaft, and an elastomeric stripper element attached to the inner tubular shaft for sealing around the tubular.