Drilling Apparatus Snubber Torque Application for Continuous Rotation
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Solution Overview
Problem
Drilling operations with rotary rigs face interruptions and disruptions in fluid dynamics and pressure when adding or removing tubulars, leading to costly issues like surging, formation fracturing, and stuck pipes, due to the need to stop drilling and reconnect drill strings.
Innovation Solution
A drilling apparatus with a snubber and pressure chamber that allows continuous mud circulation by applying differential torque to break and make tool joint connections, enabling the drill string to rotate and maintain steady downhole conditions during tubular additions or removals, using a differential gear mechanism and extension sub for uninterrupted drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the drill string is disconnected to add or remove tubulars, then the drilling operation can be paused for maintenance, but the drilling operation must be stopped and downhole fluid dynamic regime is significantly upset
Solution Approach 1:
The apparatus pre-positions a second snubber and pressure chamber system below the first snubber, ready to engage immediately when the drill string needs to be disconnected. This preliminary arrangement allows the drilling operation to continue uninterrupted while tubulars are added or removed, as the lower snubber can take over the rotation function without stopping the drill string.
Solution Approach 2:
The system divides the snubber function into two separate units: an upper snubber for making/breaking tool joint connections and a lower snubber for maintaining continuous rotation. This segmentation allows the upper snubber to disengage for tubular addition while the lower snubber maintains continuous rotation, eliminating the need to stop the drilling operation.
2Ease of manufacture
If the drill string is disconnected for tubular addition, then maintenance can be performed, but connection time increases and steady state downhole conditions are lost
Solution Approach 1:
The lower snubber maintains continuous rotation of the drill string during the entire tubular addition process, eliminating the need to stop the drilling operation. This continuous rotation maintains steady downhole conditions and prevents the loss of time that would otherwise occur during connection operations.
Solution Approach 2:
The pressure chamber and seals are pre-positioned between the upper and lower snubbers, ready to engage immediately when needed. This preliminary arrangement allows for rapid connection-making without time loss, as the system is already configured to maintain continuous rotation while facilitating tubular addition.
3Ease of manufacture
If the upper snubber applies torque to break tool joint connections, then tubulars can be added, but the drill string rotation may be affected
Solution Approach 1:
The torque application function is segmented between the upper snubber (for breaking connections) and the lower snubber (for maintaining rotation). The upper snubber can apply high torque to break tool joint connections while the lower snubber maintains steady rotation, preventing any affect on the drill string rotation speed.
Solution Approach 2:
The lower snubber acts as an intermediary that decouples the torque application from the rotation function. It receives the rotation function from the drill string and maintains it independently, allowing the upper snubber to apply torque for connection breaking without affecting the rotation speed.
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 continuous drilling and rotation, maintaining a steady fluid dynamic state downhole, reducing connection times, minimizing disruptions, and improving safety by allowing tool joint connections without stopping the drill string, thus enhancing well control and reducing drilling problems like differential sticking and pressure variations.
Implementation Method 1
the snubber is adapted to apply sufficient torque to a rotating tubular to make or break tool joint connections
Implementation Method 2
the snubber and the drill string drive breaking the tool joint connection due to differential torque between the snubber and the drill string drive while they are gripping the tubulars above and below the tool joint
Implementation Method 3
a pressure chamber located beneath the snubber and comprising seals, a blind ram and a mud inlet and outlet
Implementation Method 4
the pressure chamber being sealed
Implementation Method 5
the apparatus comprises a drill string drive below the pressure chamber, said drive being adapted to apply torque and support to a rotating drill string during said connections
Implementation Method 6
the snubber and the drill string drive gripping tubulars above and below a tool joint
Implementation Method 7
using a differential gear mechanism and extension sub for uninterrupted drilling
Data Source
AI summary
A drilling apparatus (1) provides continuous rotation, and in some embodiments also vertical translation of the drill bit, such that weight can be kept on the bit and drilling can continue uninterrupted during connections. The connection is made in a pressure chamber formed by seals (2, 4) and spacers (15, 16). An upper snubber (5) grips the drill string above the joint and a lower snubber (6) grips it below the joint. The top drive is decoupled as the snubbers take over drill string drive, and apply a differential torque so that the connection is made. This achieves continuous rotation during the connection, and by use of an extension sub (18) drilling is also continuous.