Wellbore Pressure Control via Segregated Fluid Columns
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Solution Overview
Problem
Current wellbore pressure control methods, such as downhole deployment valves and snubbing units, are prone to failure, time-consuming, and expensive, and often ineffective, especially in underbalanced and managed pressure drilling operations, where precise pressure control is crucial to prevent fluid loss and formation damage.
Innovation Solution
A well system and method utilizing a rotating control device (RCD) and a pressure and flow control system with a hydraulics model and automated controller to regulate bottom hole pressure by isolating the annulus and applying backpressure through a choke manifold, while using a barrier substance to segregate fluids and maintain pressure control during operations like drilling and completion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If specialized equipment like downhole deployment valves and snubbing units is used for wellbore pressure control, then pressure control capability is provided, but reliability is reduced due to equipment failure and leakage
Solution Approach 1:
The patent extracts and eliminates the need for complex downhole deployment valves and snubbing units by using a simpler approach: circulating barrier fluid through standard drilling equipment to create fluid segregation and pressure control. This removes unreliable specialized components while maintaining pressure control functionality.
Solution Approach 2:
The system uses the drilling fluid circulation system itself to provide pressure control functionality. The barrier fluid is circulated through the drill string and annulus using existing pumps and flow control equipment, allowing the system to self-regulate pressure without additional specialized components.
2Reliability
If specialized equipment like snubbing units is installed for pressure control, then pressure sealing capability is achieved, but installation time and operational time increase significantly
Solution Approach 1:
The barrier fluid circulation operates continuously throughout drilling operations, maintaining pressure control without interruption. The fluid segregation is established once and persists through tripping, logging, and completion operations, eliminating repeated installation and setup times required by snubbing units.
Solution Approach 2:
The barrier fluid is circulated and fluid segregation is established in advance before operations like tripping or logging begin. This preliminary action creates the pressure control environment needed for subsequent operations without requiring time-consuming equipment installation at each stage.
3Reliability
If downhole deployment valves are used for pressure control, then pressure containment is provided, but equipment failure and leakage occur reducing effectiveness
Solution Approach 1:
The barrier fluid acts as an intermediary substance that provides pressure containment through fluid pressure rather than mechanical valves. The density difference between barrier fluid and drilling fluid creates a self-contained pressure barrier that eliminates reliance on mechanical downhole deployment valves prone to failure.
4Measurement precision
If conventional pressure control methods are used, then basic pressure control is achieved, but precision and control accuracy are insufficient for underbalanced and managed pressure drilling
Solution Approach 1:
The system incorporates pressure sensors and flow meters that continuously monitor wellbore pressure and fluid flow. This feedback information is used to adjust pump rates and choke openings in real-time, enabling precise pressure control for underbalanced and managed pressure drilling operations.
Solution Approach 2:
The pressure control system is dynamically adjustable through variable speed pumps and adjustable chokes that can be modified in real-time based on drilling conditions. This allows precise adaptation of pressure control parameters during operations without requiring complex fixed-pressure equipment.
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
Enables precise control of wellbore pressure, reducing the risk of fluid loss and formation damage, and eliminates the need for costly and unreliable equipment like snubbing units, by maintaining consistent pressure and fluid segregation during various well operations.
Implementation Method 1
a first fluid and a second fluid of different densities may be present in the wellbore below the barrier substance
Implementation Method 2
regulate bottom hole pressure by isolating the annulus and applying backpressure through a choke manifold
Implementation Method 3
fluids exposed to drilled-through formations and zones... maintain precise control over pressures
Data Source
AI summary
A method of controlling pressure in a wellbore can include placing a barrier substance in the wellbore while a fluid is present in the wellbore, and flowing another fluid into the wellbore while the first fluid and the barrier substance are in the wellbore. The first and second fluids may have different densities. Another method can include circulating a fluid through a tubular string and an annulus formed between the tubular string and the wellbore, then partially withdrawing the tubular string from the wellbore, then placing a barrier substance in the wellbore, then partially withdrawing the tubular string from the wellbore and then flowing another fluid into the wellbore. A well system can include at least two fluids in a wellbore, the fluids having different densities, and a barrier substance separating the fluids.