Single Packer Structure for Wellbore Fluid Sampling
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Solution Overview
Problem
Straddle packer configurations in wellbores are limited by mechanical stresses and restricted expansion ratios, making it difficult to collect fluid samples effectively, especially under high drawdown pressure differentials and in weak formations.
Innovation Solution
A single packer system with an outer flexible skin and integrated drains, featuring an expansion mechanism and extensible members to facilitate larger expansion ratios and higher drawdown pressure differentials, allowing for focused sampling and efficient fluid collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If straddle packer configuration is used, then fluid collection between two packers is achieved, but mechanical stresses limit expansion ratio and drawdown pressure differential
Solution Approach 1:
The invention extracts the sealing function from a dual packer configuration and concentrates it into a single packer structure. The single packer includes an outer flexible skin with sealing elements that perform the isolation function previously requiring two separate packers, thereby eliminating the mandrel stress limitations of the straddle configuration while maintaining effective fluid collection capability
Solution Approach 2:
The invention employs an outer flexible skin as the primary structural component that provides both sealing and expansion capabilities. This flexible skin can be expanded to achieve larger expansion ratios without the mechanical stress constraints of rigid dual-packer mandrels, allowing higher drawdown pressure differentials to be applied during fluid collection operations
2Adaptability or versatility
If dual packer configuration is used, then region isolation is achieved, but device complexity and cost increase
Solution Approach 1:
The invention merges the functions of two separate packers into a single integrated packer structure. The single packer combines the sealing, isolation, and fluid collection functions that previously required two distinct packers, thereby reducing device complexity and cost while maintaining adaptability for focused fluid collection at specific wellbore intervals
Solution Approach 2:
The single packer is designed as a multi-functional device that performs region isolation, fluid collection, and supports various sampling configurations (single drain, multiple drains, different patterns) within one structure. This universal design eliminates the need for multiple specialized packers while maintaining versatility across different fluid collection applications
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 single packer system enables larger expansion ratios, supports formation zones better, and reduces stress on the mandrel, allowing for effective fluid collection even in weak formations with larger drawdowns and improved sampling precision.
Implementation Method 1
The single packer is designed with an outer flexible skin and one or more drains coupled to the outer flexible skin. A mandrel is positioned within the outer flexible skin, and an expansion mechanism is provided to control expansion of the outer flexible skin. For example, portions of the outer flexible skin can be expanded into sealing engagement with a surrounding wall.
Data Source
AI summary
A technique involves collecting formation fluids through a single packer having at least one drain located within the single packer. The single packer is designed with an outer flexible skin and one or more drains coupled to the outer flexible skin. A mandrel is positioned within the outer flexible skin, and an expansion mechanism is provided to control expansion of the outer flexible skin to selectively create sealing engagement with a surrounding wall.