Heave Compensation Control for Stable Bottom Hole Pressure
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Solution Overview
Problem
Existing systems fail to effectively compensate for bottom hole pressure fluctuations caused by surge and swab effects during deepwater Managed Pressure Drilling (MPD) operations, particularly due to met-ocean conditions affecting floating drilling vessels, leading to potential downtime and equipment damage.
Innovation Solution
A computer-implemented method and system that uses a control system to identify drilling states and non-drilling states, predict vessel movements, and automatically adjust pressure regulation to maintain constant bottom hole pressure by compensating for surge and swab effects through surface backpressure adjustments and mechanical compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If automated heave compensation is implemented to maintain constant bottom hole pressure during vessel motion, then pressure stability is improved, but system complexity increases
Solution Approach 1:
The system predicts vessel motion and piston effects in advance using motion models and environmental measurements. By determining compensation adjustments before the actual pressure fluctuations occur, the system can proactively maintain bottom hole pressure stability rather than reacting after deviations occur.
Solution Approach 2:
The control system continuously monitors environmental measurements, predicts vessel motion, and adjusts pressure regulation based on the relationship between predicted motion and expected piston effects. This closed-loop feedback mechanism automatically compensates for pressure fluctuations caused by heave, sway, and roll.
2Manufacturing precision
If real-time pressure regulation adjustments are made to counteract piston effects, then bottom hole pressure control is improved, but response time requirements increase
Solution Approach 1:
The system performs predictions and determines compensation adjustments in advance based on environmental measurements and motion models. This preliminary action allows the control system to prepare compensation strategies before pressure deviations occur, reducing the actual response time when adjustments are needed.
3Reliability
If the system monitors and predicts vessel motion to compensate for piston effects, then operational reliability is improved, but computational requirements increase
Solution Approach 1:
The system uses motion models to predict vessel motion and piston effects in advance based on environmental measurements. By performing computations proactively rather than reactively, the system can use simpler, less computationally intensive algorithms while still achieving reliable pressure compensation.
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
The system effectively mitigates pressure fluctuations, maintaining consistent bottom hole pressure during drilling and non-drilling states, reducing downtime and equipment damage by anticipating and counteracting piston effects caused by vessel heave, sway, and roll.
Implementation Method 1
predicting predicted movement of the drilling vessel by motion modelling the relationship between one or more environmental measurements indicative of an influence from the ocean environment on the drilling vessel and one or more vessel characteristics of the drilling vessel
Implementation Method 2
the drillstring held during the vessel motion being expected to produce a first piston effect that changes the downhole pressure in the wellbore
Data Source
AI summary
A computer system manages drilling operations in an ocean environment. The system differentiates between nondrilling and drilling states in a closed-loop fluid system on a drilling vessel. In the non-drilling state, where the drillstring is held on the vessel during motion, a “piston effect” can alter downhole pressure. The system adjusts the surface backpressure automatically to counteract this pressure change and maintains the pressure within acceptable limits. The adjustment process incorporates a motion model that predicts the vessel's movement based on environmental factors and the vessel's characteristics. This model uses environmental measurements to calculate the necessary backpressure adjustments, ensuring stable downhole conditions despite the vessel's motion.