Downhole Pressure Maintenance Device for Wellbore Integrity
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Solution Overview
Problem
The existing downhole pressure maintenance systems fail to maintain a stable pressure within isolated annuli of wellbores, leading to potential wellbore collapse or influx of sand, especially during gravel packing operations, due to pressure imbalances between the wellbore and completion string annuli.
Innovation Solution
A pressure maintenance device (PMD) is introduced, which includes dual or single port configurations with valves and a restrictor, connected between the wellbore and completion string annuli, to regulate pressure differentials and maintain a predetermined pressure range by controlling fluid flow, using a reference pressure assembly and pressure sensors to adjust valve positions based on pressure thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If packers are set to isolate production zones from wellbore hydrostatic pressure, then gravel packing operations can be performed, but the wellbore annulus pressure drops causing wellbore collapse or sand influx
Solution Approach 1:
A pressure maintenance device is introduced as an intermediary component between the completion string annulus and the wellbore annulus. This device includes a valve and restrictor that regulate fluid flow to maintain pressure differential, preventing wellbore collapse while enabling gravel packing operations in isolated zones
Solution Approach 2:
The pressure maintenance device is installed and configured before gravel packing operations begin. The valve is initially closed to establish pressure balance, and the system is prepared in advance to prevent pressure drops that would cause wellbore collapse during subsequent isolation and packing operations
2Adaptability or versatility
If the wellbore annulus is isolated from hydrostatic pressure, then production zones can be independently packed, but pressure imbalance causes sand influx in unconsolidated cased holes
Solution Approach 1:
The pressure maintenance device acts as a mediator that maintains the necessary pressure differential between the isolated completion string annulus and the wellbore annulus. This prevents sand influx in unconsolidated formations while allowing independent multi-zone completion operations
Solution Approach 2:
The system uses pressure differential feedback through the restrictor and valve mechanism to automatically regulate fluid flow. When pressure drops occur in the isolated annulus, the feedback mechanism opens the valve to restore pressure balance, preventing sand influx while maintaining multi-zone isolation capability
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 PMD effectively maintains a stable pressure within the wellbore annuli, preventing collapse and sand influx, ensuring the integrity of the wellbore during gravel packing and production operations by regulating pressure differentials and maintaining a predetermined pressure range.
Implementation Method 1
the valve opens to allow the fluid from the internal region to flow to the external region when a pressure differential between a pressure within the external region and a pressure within the internal region exceeds a pressure threshold
Implementation Method 2
a restrictor that regulates flow of the fluid through the flow path
Data Source
AI summary
A method and apparatus that includes an elongated base pipe having an external surface at least partially defining an external region and an internal surface at least partially defining an internal region; and a pressure maintenance device disposed in the base pipe and comprising: a flow path that extends between the internal region and the external region; and a valve having a gas charged chamber, the valve allowing the flow of a fluid from the internal region to the external region through the first flow path when a pressure differential between a pressure associated with the internal region and a pressure associated with the gas charged chamber is less than a maximum pressure threshold and when a pressure differential between the external region and the pressure associated with the gas charged chamber is greater than a minimum pressure threshold.