Drill Bit Trajectory Control via Bit Walk Prediction
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Solution Overview
Problem
Directional drilling is complicated by the complex interaction of forces between the drill bit and the subterranean formation, leading to issues like bit walk and wellbore spiraling, which existing technologies struggle to predict and control accurately.
Innovation Solution
A method involving a directional drill-ahead simulator that constructs a BHA model to calculate forces and motions, using axial and lateral motion drill bit models to predict bit walk and wellbore spiraling, and adjusts drilling parameters to steer the drill bit trajectory effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lateral force is applied to the drill bit, then the drill bit can adjust its trajectory direction, but the drill bit walks or drifts from the intended path reducing drilling precision
Solution Approach 1:
The system performs preliminary calculation of bit walk and wellbore spiraling using BHA and bit models before actual drilling occurs. The directional drill-ahead simulator computes predicted trajectories and adjusts drilling parameters in advance to compensate for expected bit walk, allowing the drill bit to follow the intended path more accurately despite lateral forces.
Solution Approach 2:
The system continuously monitors actual drilling parameters and compares them with predicted values from the simulator. Based on this feedback, the system adjusts drilling parameters in real-time to compensate for bit walk and maintain trajectory accuracy, resolving the contradiction between trajectory control flexibility and drilling precision.
2Measurement precision
If complex force interactions between drill bit and formation are considered, then prediction accuracy improves, but computational complexity and time increase
Solution Approach 1:
The system segments the complex drilling system into distinct models: BHA model, bit model, axial motion model, and lateral motion model. Each model handles specific aspects of the force interactions separately, making the overall computation more manageable while still capturing the complex interactions between drill bit and formation.
Solution Approach 2:
The system performs preliminary calculations using simplified models to obtain initial trajectory predictions, then refines these predictions by incorporating more complex force interaction models. This staged approach allows accurate prediction of bit walk and wellbore spiraling without requiring all complex calculations to be performed simultaneously, reducing computational burden.
3Productivity
If real-time parameter adjustment is implemented, then drilling efficiency improves, but operational complexity increases
Solution Approach 1:
The directional drill-ahead simulator operates autonomously to calculate bit walk, predict trajectories, and recommend parameter adjustments without requiring constant manual intervention. The system self-adjusts drilling parameters based on real-time conditions and predictions, improving drilling efficiency while minimizing the operational complexity burden on drill operators.
Data Source
AI summary
A method of controlling drill bit trajectory in a subterranean formation includes receiving drilling parameters for operating a specific bottomhole assembly (BHA), constructing, with a computer processor, a directional drill-ahead simulator including a computer model of the BHA and the subterranean formation, calculating axial motion and lateral motion of a drill bit connected to a bottom end of the BHA using formation parameters and drilling parameters, predicting bit walk of the drill bit by accounting for and calculating contact forces and frictional forces between the BHA and a wall of a borehole in the subterranean formation using the computer model of the BHA, and determining an adjusted drill bit trajectory to account for the predicted bit walk. The method includes determining adjusted drilling parameters for operating the BHA to substantially follow the adjusted drill bit trajectory and operating the BHA according to the adjusted drilling parameters.