Flow Splitting Device Flexible Sealing Prevents Jamming
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Solution Overview
Problem
In gas reverse circulation drilling, existing flow splitting devices with an outer diameter close to the wellbore size often cause drill pipes to jam due to large falling objects, leading to operational inefficiencies and reduced service life.
Innovation Solution
A flow splitting device with a flexible sealing mechanism that includes a rotatable upper joint with a flexible sealing ring and wear-resistant elements, allowing for radial sealing contact with the wellbore wall and preventing jamming, while a flow guiding member directs gas flow effectively through the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer diameter of the flow splitting device is made close to the size of the wellbore to effectively block the annulus, then the sealing performance is improved, but the drill pipe easily gets jammed due to large falling objects from the wellbore wall
Solution Approach 1:
The flow splitting device is divided into an upper joint and a lower joint connected by an inner tube, creating a segmented structure. This segmentation allows the upper joint to be positioned higher in the wellbore where it can seal against the wellbore wall, while the lower joint maintains a smaller outer diameter to prevent jamming with falling objects. The segmentation enables different parts of the device to have different diameter characteristics optimized for their specific functions.
Solution Approach 2:
The sealing function is transferred from the radial dimension (outer diameter of the entire device) to the axial dimension (positioning of the upper joint higher in the wellbore). By using the axial position to achieve sealing through the flexible sealing mechanism, the lower joint can maintain a smaller radial dimension that prevents jamming with falling objects while still achieving effective annulus blocking through the upper joint's sealing action.
2Strength
If the flow splitting device uses all-metal material to ensure strength and durability, then the structural strength is improved, but the service life is reduced due to wear from rotation against the wellbore wall
Solution Approach 1:
The flexible sealing mechanism uses localized non-metallic sealing elements (such as rubber or polymer materials) only at the specific contact point with the wellbore wall, while the rest of the flow splitting device maintains all-metal construction for overall structural strength. This local quality change allows the sealing surface to have low friction and high wear resistance against the wellbore wall, extending service life, while the metal body provides the necessary structural integrity.
Solution Approach 2:
The flow splitting device employs composite material construction, combining metal materials for the main body (upper joint, lower joint, inner tube) to provide structural strength, with non-metallic flexible sealing materials for the sealing mechanism that contacts the wellbore wall. This composite approach leverages the advantages of both material types: metal provides strength and durability, while the flexible non-metallic material provides low-friction sealing that reduces wear during rotation, thereby extending service life.
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 prevents drill pipe jamming and extends the service life of the flow splitting device by allowing larger objects to pass through and maintaining effective sealing, ensuring efficient gas flow and cutting transport during drilling operations.
Implementation Method 1
a flexible sealing mechanism is provided on the upper joint, so that the upper joint is rotatable relative to the flexible sealing mechanism, the flexible sealing mechanism extending radially outward relative to the upper joint and the lower joint to form a sealing contact with a wellbore wall
Data Source
AI summary
A flow splitting device for gas reverse circulation drilling, including: an upper joint for connecting with a double-wall drill pipe; an inner tube which is arranged in the upper joint and defines a first passageway in communication with an inner chamber of the double-wall drill pipe, a second passageway in communication with an annular space in the double-wall drill pipe formed between the inner tube and the upper joint; a lower joint, having an upper end fixedly connected with the upper joint and a lower end for connecting with a drill tool; and a flow guiding member provided between the upper joint and the lower joint. A flexible sealing mechanism is provided outside the upper joint. The flexible sealing mechanism extends radially outward relative to the upper joint and the lower joint to form a sealing contact with a wellbore wall.