Annulus Pressure Setpoint Correction Using Real-Time Drilling Measurements
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Solution Overview
Problem
Current wellbore pressure control technologies face challenges in maintaining precise pressure control during drilling, especially in underbalanced and managed pressure drilling operations, particularly in situations with narrow pore pressure/fracture pressure margins, where existing methods struggle to accurately regulate bottom hole pressure and prevent fluid loss or influx.
Innovation Solution
The implementation of a real-time pressure control system using a hydraulics model, pressure sensors, and a pressure and flow control system that applies a correction factor to friction pressure calculations based on downhole measurements, allowing for continuous adjustment of annulus pressure setpoints to maintain desired wellbore pressures, even during non-circulation periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If real-time pressure control using downhole measurements is implemented, then pressure control precision is improved, but system complexity increases
Solution Approach 1:
The system continuously measures actual bottom hole pressure and annulus pressure at downhole locations, compares these measurements to target pressure values, and automatically adjusts choke positions to maintain desired pressure conditions. This closed-loop feedback control enables precise pressure management despite increased system complexity from the additional sensors and real-time processing requirements.
Solution Approach 2:
The patent replaces traditional mechanical pressure control methods with a system that uses electronic pressure sensors, digital signal processing, and automated choke control. This substitution of mechanical systems with electronic and computational systems enables more precise measurements and control while managing the complexity through automation.
2Measurement precision
If multiple downhole pressure sensors are deployed, then pressure measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The system divides the wellbore into multiple measurement zones by deploying separate pressure sensors at different downhole locations (e.g., near the drill bit, in the annulus). Each sensor independently measures pressure at its specific location, allowing the system to characterize pressure distribution throughout the wellbore. This segmentation enables accurate pressure measurement while managing complexity through modular sensor placement.
Solution Approach 2:
The pressure sensors serve multiple functions: they measure bottom hole pressure, measure annulus pressure, detect pressure changes during drilling operations, and provide data for automated choke control. This multi-functionality justifies the added complexity by delivering comprehensive pressure data that supports both monitoring and control objectives.
3Reliability
If friction pressure correction factor is calculated using real-time measurements, then pressure control reliability is improved, but calculation complexity increases
Solution Approach 1:
The system calculates a friction pressure correction factor that dynamically adapts to changing drilling conditions by using real-time measurements of actual pressure versus predicted pressure. This dynamic correction accounts for variations in mud density, flow rate, and wellbore geometry, improving the reliability of pressure control calculations while managing complexity through automated real-time computation.
Data Source
AI summary
A method of controlling pressure in a wellbore can include determining a real time wellbore pressure PwbRT1 at a pressure sensor in the wellbore, calculating hydrostatic pressure Ph1 at the pressure sensor, determining a real time annulus pressure PaRT, calculating friction pressure Pf due at least to circulation of the fluid through the wellbore and depth in the wellbore, calculating a friction pressure correction factor CFPf1 equal to (PwbRT1−Ph1−PaRT)/Pf, and controlling operation of a pressure control device, based on the friction pressure correction factor CFPf1. The method can further include determining a desired wellbore pressure PwbD1 at the pressure sensor, calculating an annulus pressure setpoint PaSP1 equal to PwbD1−Ph1−(Pf*CFPf1), and adjusting the pressure control device as needed to maintain PaRT equal to PaSP1.