Investigation on Hydrate Formation and Viscosity of the Gas–Water System in Lingshui Gas Field of South China Sea

Abstract

With gas production moving into the deep sea, the prediction of hydrate formation and blockage prevention are of great significance in flow assurance. In this work, hydrate formation experiments at a wide range of pressures and temperatures based on the production conditions of the Lingshui gas field were conducted by a high-pressure rheometer, and the evolution of viscosity was investigated. The experimental results showed that the slurry viscosity changed in stages during the formation of the hydrate, and the aggregation of hydrate particles was the essential cause of the significant increase in viscosity. The more severe the temperature and pressure conditions, the faster the hydrate formation and the greater the tendency of increasing viscosity. In experiments, the formation of hydrates would lead to severe blockages when the pressure exceeded 10 MPa. Compared with 100 and 300 rpm, the average hydrate formation rate was the fastest at 200 rpm. In addition, the relationship between hydrate volume fraction and viscosity was analyzed, and a critical hydrate volume fraction was proposed for a sharp increase in viscosity, which had a low value at high pressures and low temperatures and tended to cause blockages. This study can provide helpful theoretical support for hydrate formation prediction and blockage prevention in natural gas production.

Permeability Anisotropy of Hydrate-Bearing Sediment during Consolidation Process: Insights from CT Scanning and Pore Network Modeling

“…Natural gas hydrate (NGH) represents a novel energy source characterized by substantial energy conversion efficiencies and vast reserves. − It is considered that the global carbon reserves of NGH is about 1.8 × 10 3 Gt, which is equivalent to the volume of standard natural gas of 3.0 × 10 15 m 3 and more than 2 times the aggregate carbon content found in conventional fossil fuels. , Therefore, the realization of the commercial exploitation and utilization of NGH hold strategic importance for the sustained advancement of our nation in the long run. − Currently, nations globally are pivotal in transitioning from experimental exploitation to commercial endeavors . Ensuring secure, efficient, and uninterrupted exploitation stands as a fundamental prerequisite for the prospective utilization of marine NGH resources and commercial exploitation in China in the future. , …”

Experimental study on the effect of quaternary ammonium salt + monoethylene glycol compound to methane hydrate agglomeration in oil-water system

“…The formation and agglomeration of NGH occurring in subsea facilities might induce critical risk for the safety of production or transportation, and cause significant economic losses [ 2 ]. Therefore, natural gas hydrate has been one of the biggest menaces for the flow safety in the offshore oil and gas industries [ 3 ].…”