Drillable Billet Bi-Centered Bit Sidetrack
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Solution Overview
Problem
Conventional methods for sidetracking a wellbore from an existing wellbore face challenges in steering the drillbit due to resistance from the existing wellbore, often requiring multiple trips to adjust drillstring angles and risking blockages, especially when trying to access hydrocarbon deposits at a distance.
Innovation Solution
A drillable billet is installed in the existing wellbore with a pre-formed path to guide a bi-centered drillbit, allowing it to exit the wellbore and create a sidetrack by reaming out a larger hole, enabling directional drilling with a single trip and minimizing friction and blockages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cement plug is used to create resistance for sidetrack drilling, then the drillbit can be steered away from the existing wellbore, but the original wellbore below the sidetrack location is blocked and further production is prevented
Solution Approach 1:
The patent introduces a drillable billet as an intermediary object that provides the necessary resistance for drillbit steering while being removable. The billet serves as a temporary mediator that enables the sidetrack operation without permanently blocking the original wellbore, as it can be drilled through by the bi-centered drillbit to create the new wellbore path
Solution Approach 2:
The invention changes the physical state and properties of the plug material from permanent (cement) to temporary and drillable (billet material). This parameter change allows the plug to transition from a blocking state to a removable state, enabling both steering functionality and future wellbore access
2Loss of time
If an aluminum plug is used instead of cement plug, then installation is faster and easier, but the plug is sloppy in the wellbore and likely to fall down and block the side track when the drill string is pulled out
Solution Approach 1:
The drillable billet is pre-installed and positioned in the wellbore before the sidetrack drilling operation begins. This preliminary action ensures the billet is in place to provide steering resistance during drilling, and its drillable nature ensures it won't fall down and block the wellbore when the drill string is pulled out
Solution Approach 2:
The drillable billet is designed as a temporary, disposable object that serves its purpose during the sidetrack drilling operation and then is drilled through and removed. This eliminates the need for permanent plugs that could cause future problems, while providing reliable temporary support during the critical drilling phase
3Ease of operation
If an aggressive angle motor is used to ensure the drillbit fully exits the existing wellbore, then the drillbit can create a sidetrack, but the wellbore creates too much friction when liner or casing is inserted due to excessive curvature
Solution Approach 1:
The bi-centered drillbit provides dynamic control over the drilling angle and wellbore curvature. The unique bit geometry allows the drilling path to be controlled to achieve adequate exit from the existing wellbore while maintaining a reasonable curvature that minimizes friction during subsequent liner or casing installation
Solution Approach 2:
The invention changes the drilling parameters by using a bi-centered drillbit that can adjust the wellbore curvature and angle. This allows optimization of the drilling path to balance two competing requirements: sufficient exit distance from the existing wellbore and acceptable curvature to minimize friction during casing installation
4Manufacturing precision
If multiple trips are made to adjust drillstring angles and replace motors, then the drillbit can reach the target formation, but time is lost and drilling efficiency is reduced
Solution Approach 1:
The drillable billet is pre-installed with the appropriate geometry and orientation to guide the bi-centered drillbit along the desired path. This preliminary preparation eliminates the need for multiple trips to adjust angles and replace motors, as the drilling operation can proceed continuously with a single drillstring insertion
Solution Approach 2:
The bi-centered drillbit is a universal tool that can drill the sidetrack wellbore at the correct angle without requiring multiple specialized operations. The single drillbit design performs multiple functions: creating the initial path, maintaining proper angle, and reaching the target formation, all in one continuous operation
Data Source
AI summary
Drilling a sidetrack wellbore out of the side of an existing wellbore utilizing a drillable billet having a path formed in the billet to lead a bi-centered drillbit to kick-out from the wellbore and form a sidetrack wellbore. The bi-centered bit is arranged for the lands of the pilot section to follow the path of the billet while the wings of the ream out a portion of the billet and also ream out the earth to form the full dimension sidetrack wellbore. The bi-centered bit is used to drill the sidetrack wellbore to the target zone so that the entire drilling process extends from the existing wellbore to the target zone without a mandatory withdrawal of the drillstring from the wellbore.