Development of a high pressure micromechanical force apparatus

Area of Science:

• Petroleum Engineering
• Materials Science
• Chemical Engineering

Background:

• Gas hydrate formation and plugging in subsea oil and gas flowlines are significant operational risks.
• Low temperatures and high pressures in subsea environments promote hydrate formation and agglomeration, leading to pipeline blockages.

Purpose of the Study:

• To develop and utilize a novel high-pressure micromechanical force (MMF) apparatus for direct measurement of cohesive forces between gas hydrate particles.
• To gain a deeper understanding of the hydrate agglomeration process, a critical factor in hydrate plug formation.

Main Methods:

• A high-pressure MMF apparatus was designed, capable of withstanding up to 10 MPa, using two cantilever fibers to manipulate hydrate particles.
• Water droplets were converted to hydrates on cantilever tips, and cohesive forces were measured under controlled high-pressure conditions.
• CH4/C2H6 mixed hydrates were prepared and tested to demonstrate the apparatus's stability and measurement capabilities.

Main Results:

• The developed MMF apparatus successfully measured cohesive forces between gas hydrate particles.
• Average cohesive force for gas hydrates was measured at approximately 43 mN/m.
• This value is approximately 10 times higher than the cohesive force observed for cyclopentane hydrates in cyclopentane liquid (~4.3 mN/m).

Conclusions:

• The new high-pressure MMF apparatus provides direct quantitative insights into gas hydrate particle cohesion.
• The significantly higher cohesive forces measured for gas hydrates underscore their propensity for agglomeration.
• These findings are crucial for improving models and mitigation strategies for hydrate plug formation in oil and gas flowlines.