Triaxial Shear Cell for Complex Stress at Hydrate-Sediment Interfaces
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Solution Overview
Problem
Existing interfacial shear apparatuses fail to simulate the low-temperature and high-pressure conditions necessary for hydrate-bearing sediment formation, suffer from sealing issues, and cannot conduct complex stress path shear experiments, leading to inaccurate data and stability concerns during wellbore operations.
Innovation Solution
A novel experimental apparatus and method using a triaxial shear pressure cell, torsional and axial loading device, and data acquisition system to simulate complex stress states, ensuring accurate measurement of interfacial shear characteristics under controlled conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If existing interfacial shear apparatuses are used, then the structure is simple, but they fail to simulate low-temperature and high-pressure conditions for hydrate-bearing sediment formation
Solution Approach 1:
The apparatus is divided into distinct functional modules: a pressure chamber for high-pressure environment, a water bath device for low-temperature control, a triaxial shear system for stress application, and a data acquisition system. Each module independently performs its function, allowing complex low-temperature and high-pressure simulation while maintaining manageable system complexity through modular design.
2Stress or pressure
If existing interfacial shear apparatuses are used, then the structure is simple, but they suffer from sealing issues and cannot achieve high-pressure sealing
Solution Approach 1:
A dedicated pressure chamber serves as an intermediary component that isolates the high-pressure environment from the rest of the apparatus. The chamber is equipped with specialized sealing mechanisms including O-rings and pressure-resistant flanges, enabling reliable high-pressure containment while protecting other components from direct exposure to extreme pressures.
3Adaptability or versatility
If existing interfacial shear apparatuses are used, then operation is simple, but they cannot conduct complex stress path shear experiments under coupling action of vertical load and circumferential torque
Solution Approach 1:
The loading system is designed with multi-functionality to perform various stress path experiments. It includes a vertical loading mechanism for axial stress, a torsional loading mechanism for circumferential torque, and a confining pressure system for radial stress. These integrated mechanisms enable complex coupled stress experiments while maintaining a unified control interface that manages all loading functions through a single system.
4Measurement precision
If existing interfacial shear apparatuses are used, then the structure is simple, but the loose connection of force transmission seat leads to inaccurate experimental data
Solution Approach 1:
The force transmission seat is pre-loaded and pre-positioned during the assembly phase before experiments begin. Adjustment mechanisms are built into the assembly process to ensure precise positioning and tight connections of all force transmission components. This preliminary setup ensures accurate data collection during experiments without requiring complex real-time adjustment mechanisms.
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 measurement of mechanical parameters at the sediment-structure interface, supporting safe and stable wellbore operations by simulating realistic stress conditions and providing reliable data acquisition.
Implementation Method 1
a water bath device (6), wherein the water bath device (6) is provided with a water bath jacket (18) sleeved around the high-pressure sealing cover (19)
Implementation Method 2
a first pressure-volume controller (5), a second pressure-volume controller (7)
Data Source
AI summary
An experimental apparatus for studying an interfacial shear characteristic between a hydrate-bearing sediment and a structure includes a triaxial shear pressure cell, a torsional and axial loading device, a methane gas source, an upper computer, a first pressure-volume controller, a water bath device, a second pressure-volume controller, an oil tank, a back pressure valve, a gas-water separator, a gas flowmeter, and a data acquisition system, where the triaxial shear pressure cell includes an upper pressing plate, an upper fixed disc, a loading rod, a pressure chamber upper cover, a high-pressure sealing cover, a lower rotating base disc, a thermal insulation plate, a lower pressing plate, a top cap, and a base. The experimental apparatus can achieve in-situ artificial hydrate formation for the study. The multi-directional load control-based shear method supports interfacial shear experiments under a complex stress path, providing hardware support for studying the interfacial shear mechanical characteristic.