MPD Control System Elasticity Compensation for Bottomhole Pressure
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Solution Overview
Problem
Conventional drilling techniques fail to accurately control bottomhole pressures in extended reach wells due to neglecting the elasticity of drill pipes, leading to issues like fluid invasion, permeability damage, and lost circulation, which are not properly addressed by current methods.
Innovation Solution
Incorporating a torque and drag model into the Managed Pressure Drilling (MPD) control system to calculate the elasticity of the drill string, which is used in a real-time hydraulics model to determine setpoint pressures, and a rotating control device (RCD) is employed to manage annular pressure, ensuring precise control of wellbore pressure through a closed-loop system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional drilling calculations are used to control bottomhole pressures, then the control system is simpler, but the pressure control accuracy deteriorates due to neglecting drill pipe elasticity
Solution Approach 1:
The patent transforms the pressure control approach by changing the calculation parameters to include drill pipe elasticity effects. The system incorporates elastic elongation and contraction of the drill string as dynamic parameters that affect bottomhole pressure, moving beyond static conventional calculations to include time-varying elastic parameters in the pressure model.
Solution Approach 2:
The patent implements a feedback mechanism where measured bottomhole pressures and drill string movements are continuously fed back to update the pressure calculations. This closed-loop feedback allows the system to adjust for elastic effects in real-time, improving pressure control accuracy while managing system complexity through automated feedback processing.
2Reliability
If drill string elasticity is neglected in pressure calculations, then the calculations are simpler, but fluid invasion and formation damage occur due to inaccurate pressure control
Solution Approach 1:
The patent changes the calculation model by incorporating elastic parameters such as drill string modulus of elasticity, cross-sectional area, and length variations. These parameter changes enable the model to predict actual bottomhole pressures more reliably, preventing fluid invasion while the complexity is managed through standardized elastic parameter databases.
3Productivity
If precise annular pressure control is implemented, then non-productive time is reduced, but the system complexity increases due to multiple control points and continuous monitoring
Solution Approach 1:
The patent employs feedback control where pressure measurements from multiple depths are continuously monitored and fed back to adjust the surface pressure control. This automated feedback system maintains precise annular pressure control across multiple control points, reducing non-productive time while managing complexity through real-time automated adjustments rather than manual intervention.
Solution Approach 2:
The patent creates a universal pressure control system that can manage multiple control points and depths through a single integrated control framework. The system uses a unified pressure model that accounts for elastic effects throughout the entire drill string, allowing one control system to handle multiple measurement and control locations simultaneously.
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 approach enhances the accuracy of bottomhole pressure control, reducing non-productive time, mitigating incidents like differential sticking and lost circulation, and allowing for extended casing points and increased penetration rates.
Implementation Method 1
the elasticity of drill pipes
Data Source
AI summary
Disclosed embodiments include systems and methods for improving the accuracy of bottom hole pressure control. One example embodiment includes a torque and drag model that calculates the elasticity of the drill string, which is included in a managed pressure drilling control system. The addition of the torque and drag calculations provide more accurate surge/swab effect calculations based on pipe movement corrected for elasticity effects. The results of these calculations will be used in a real-time hydraulics model to determine a setpoint pressure which will be utilized by a MPD choke system. Further, the real-time torque and drag models are calibrated to actual hole conditions in real-time using survey, temperature, pressure and downhole tool data to calculate friction factors in a wellbore.