Shape Memory Polymer Foam Filter for Methane Hydrate Sand Control
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Solution Overview
Problem
Conventional sand control methodologies fail to effectively manage sand production and ensure borehole stability during methane hydrate production in unconsolidated formations, particularly when using the depressurization method, as they rely on the geometric configuration of the borehole for containment, which is unstable under changing reservoir conditions.
Innovation Solution
A filtration assembly comprising a shape memory polymer foam filter surrounded by a base pipe with porous media and an exterior layer of consolidated proppant or sand that can self-adhere, allowing for sand management and flow equalization without relying on the borehole geometry, and includes a depressurization device to balance differential pressure and protect the foam from high fluid velocities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sand control methodologies are used, then the completion structure is simple, but sand production cannot be effectively controlled and borehole stability is compromised under changing reservoir conditions
Solution Approach 1:
The completion system is divided into multiple functional layers: shape memory polymer foam filter (first layer), consolidated proppant or gravel (second layer), and optionally a third filtration layer. Each layer performs specific functions - the foam provides initial filtration and borehole stability, the proppant/gravel provides structural support and additional filtration, and the third layer enhances sand control. This segmentation allows effective sand control while maintaining manageable complexity through functional specialization.
Solution Approach 2:
The invention uses composite material structures combining shape memory polymer foam with consolidated proppant or gravel. The shape memory polymer provides adaptive response to temperature and pressure changes, while the proppant/gravel provides mechanical strength and structural stability. This composite approach enables the system to maintain reliability under changing reservoir conditions without requiring overly complex active control mechanisms.
2Reliability
If the borehole geometry is relied upon for sand containment, then the completion structure is simpler, but borehole stability is lost when the borehole enlarges due to shifting sands
Solution Approach 1:
The shape memory polymer foam filter incorporates dynamic response capabilities through its shape memory properties. When exposed to temperature changes or pressure differentials during production, the foam can change its physical state and dimensions adaptively. This dynamic behavior allows the foam to maintain effective filtration and containment as the borehole geometry changes, providing borehole stability without requiring the completion structure to rigidly match the borehole shape.
Solution Approach 2:
The shape memory polymer's physical parameters (temperature, pressure sensitivity) are utilized to enable adaptive containment. As reservoir conditions change during production, the polymer responds to parameter changes by adjusting its physical state, maintaining effective sand containment even as borehole geometry evolves. This eliminates the need for complex active adjustment mechanisms while ensuring reliability under changing conditions.
3Reliability
If the foam is allowed to expand freely, then it provides better filtration, but high fluid velocities cause erosive effects that reduce service life
Solution Approach 1:
The consolidated proppant or gravel layer is placed around the shape memory polymer foam filter to provide protective cushioning before the foam is exposed to high-velocity produced fluids. This outer layer absorbs the erosive effects of high-velocity methane and water flow, protecting the foam from direct erosion while allowing the foam to maintain its expanded, effective filtration state. This beforehand protection significantly extends the service life of the foam filter.
Solution Approach 2:
The consolidated proppant or gravel acts as an intermediary protective layer between the high-velocity produced fluids and the shape memory polymer foam. This intermediary layer shields the foam from direct erosive exposure while maintaining the foam's ability to provide effective filtration. The proppant/gravel absorbs the mechanical stress and erosion, preserving the foam's integrity and extending its operational lifespan.
4Productivity
If the differential pressure is not balanced, then the production flow is higher, but uniform flow distribution across the reservoir interface is not achieved
Solution Approach 1:
The porous media structure is designed with varying local properties - different permeability zones and pore size distributions at different locations within the foam and proppant layers. This local quality variation allows the system to balance differential pressure across the reservoir interface while maintaining high overall production flow. Areas with higher pressure differentials have corresponding variations in permeability that promote uniform flow distribution, preventing channeling and ensuring reliable productivity.
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 solution effectively manages sand production, maintains borehole stability, and extends the service life of the filtration assembly by maintaining a stable geometric configuration and protecting the foam from erosive effects, even as the borehole enlarges due to shifting sands, ensuring uniform flow and prolonged functionality.
Implementation Method 1
a shape memory polymer foam filter that does not depend on the borehole for containment for sand management
Implementation Method 2
a porous media under the shaped memory polymer foam filter that can be varied in number and permeability to balance the differential pressure applied to the reservoir being produced
Implementation Method 3
consolidated proppant or sand could be deposited adjacent the shape memory foam as it is not the objective to fully occupy the borehole with the foam after it crosses its critical temperature
Data Source
AI summary
In a completion for producing methane the bottom hole assembly has a base pipe with porous media surrounding it for equalizing flow along the base pipe. A shape memory polymer foam surrounds the porous media. The borehole can be reamed to reduce produced methane velocities. Surrounding the shape memory polymer is an exterior layer of consolidated proppant or sand that can self-adhere and/or stick to the polymer foam. The proppant or sand can be circulated or squeezed into position although, circulation is preferred. The borehole may enlarge due to shifting sands in an unconsolidated formation as the methane is produced. The bottom hole assembly helps in fluid flow equalization and protects the foam and layers below from high fluid velocities during production.