Flow Sub Bypass for Continuous Drilling Fluid Circulation
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Solution Overview
Problem
Current drilling operations for oil and gas wells face interruptions and formation damage due to the need to stop circulation when adding or removing drill string joints, leading to inefficiencies and potential damage to the wellbore, and the challenge of maintaining continuous fluid flow to prevent cuttings from settling.
Innovation Solution
A continuous flow system incorporating a flow sub with a tubular housing, a rotatable ball, and an actuator mechanism that allows for continuous drilling fluid injection through a flow port, even when adding or removing drill string joints, ensuring that the drilling fluid circulation is maintained without interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If drilling operations stop to add or remove drill string joints, then drill string assembly can be completed, but drilling fluid circulation is interrupted causing formation damage and wellbore instability
Solution Approach 1:
The patent introduces a flow sub with a bypass port as an intermediary flow path. When drill string joints need to be added or removed, drilling fluid can redirect through the bypass port instead of stopping circulation entirely. This mediator flow path maintains fluid movement and pressure support in the wellbore, preventing formation damage while allowing drill string operations to proceed.
Solution Approach 2:
The flow sub is pre-installed in the drill string before drilling operations begin. The bypass mechanism is ready in advance, so when the need arises to add or remove joints, the alternative flow path is already positioned and can be activated immediately without interrupting the overall drilling process or requiring wellbore stabilization measures.
2Ease of operation
If drilling fluid circulation is stopped to add drill string joints, then joints can be connected, but cuttings settle and formation becomes damaged
Solution Approach 1:
The bypass port serves as a mediator that maintains drilling fluid circulation during drill string assembly operations. By providing an alternative flow path around the drill string connection point, it prevents cuttings from settling and formation from being damaged while still allowing workers to connect joints safely and efficiently.
3Reliability
If mud weight is increased to maintain wellbore pressure during joint changes, then wellbore remains open, but cost increases significantly
Solution Approach 1:
The bypass mechanism ensures continuous drilling fluid circulation is maintained during drill string operations. By keeping the fluid moving and the pressure support active throughout the process, there is no need to increase mud weight as a compensatory measure. The continuous action of fluid circulation naturally maintains wellbore stability without requiring additional weighting materials, thus avoiding the associated costs.
4Ease of operation
If drilling fluid flow rate is reduced during joint changes, then connection work can be performed, but cuttings settle in the wellbore
Solution Approach 1:
The bypass port acts as a mediator that maintains adequate flow velocity during drill string connections. By providing a dedicated flow path that continues to move drilling fluid at sufficient speed, it prevents cuttings from settling even when the main drill string flow is temporarily reduced or stopped for connection work, thus maintaining cuttings suspension stability.
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
This solution enables uninterrupted drilling fluid circulation, reducing the risk of formation damage and maintaining an open wellbore, while also allowing for the efficient handling of drill string extensions without stopping the drilling process, thus improving operational efficiency and reducing costs associated with mud weighting.
Implementation Method 1
The ball is disposed in the housing above the flow port, has a bore therethrough, and is rotatable relative to the housing between an open position where the ball bore is aligned with the housing bore and a closed position where a wall of the ball blocks the housing bore
Implementation Method 2
The sleeve is disposed in the housing and movable between an open position where the flow port is exposed to the housing bore and a closed position where a wall of the sleeve is disposed between the flow port and the housing bore
Implementation Method 3
The actuator comprises a cam longitudinally movable relative to the housing and operably connected to the ball and a body disposed adjacently below the ball, connected to the housing, and having a j-slot through a wall thereof. A j-slot is formed through a wall of the sleeve and a pin is fastened to the cam and extends through the body j-slot and into the sleeve j-slot.
Data Source
Figure 1A
Figure 1B~1C
Figure 2A~2B
AI summary
A flow sub for use with a drill string includes a tubular housing having a longitudinal bore therethrough and a flow port through a wall thereof and a ball. The ball is disposed in the housing above the flow port, has a bore therethrough, and is rotatable relative to the housing between an open position where the ball bore is aligned with the housing bore and a closed position where a wall of the ball blocks the housing bore. The flow sub further includes a seat disposed in the housing above the ball for sealing against the ball wall in the closed position and a sleeve disposed in the housing and movable between an open position where the flow port is exposed to the housing bore and a closed position where a wall of the sleeve is disposed between the flow port and the housing bore.