Inhibition Of Gas Hydrate In Oil And Gas Transportation

It is very easy to form gas hydratas in pipeline, wellbore and porous medium, which always do great harm to the production and transportation of the oild and gas. Therefore, it has been a very difficult for many years to prevent the forming of gas hydreates in production. Hydrates plugging problems happen easily in multi-phase pipeline at high pressures and at low temperatures. The longer the pipelines are, the greater the problem is. The formation of hydrates in pipelines must be prevented effectively and economically in multi-phase pipelines used in offshore oil-gas field development to ensure normal operation. Thus, determining formation conditions of gas hydrates correctly and recognizing proper hydrates prevention methods provide technical basis for the prevention of hydrates.This paper researches the method of restrain and mechanism of hydrates prevention. Applicable conditions, advantages and disadvantages of dehydration, control pressure, heating, mechanical and chemical method have been documented. The method of injecting chemical inhibitors is more effective and popular than other methods in inhibiting hydrates. Thus, this dissertation focuses on studing the mechanisms and experiments of chemical method of injecting inhibitors. By using high-pressure stirred hydrates reactor, inhibition efficiency of thermo-dynamical inhibitor, kinetic inhibitor and combinational agents commonly used in the site have been studied. Besides, inhibitory effects of many kinds of thermo-dynamical inhibitors and compatibility of hydrates kinetic inhibitors have been analyzed. Inhibitory effect of new type of kinetic inhibitors (PVCap) under different conditions has been investigated and scope of application has been determined. Depending on different prevention mechanisms, main agent of experimental research is kinetic inhibitor (PVCap), and the mixtures are thermo-dynamical inhibitor and anti-agglomerant. The research demonstrates that thermo-dynamical inhibitor ethanol can cause amplification of kinetic inhibitor. Besides, better compatible formulation of three hydrates in combination has been obtained in order to provide a more effective and economic inhibition method for the development of hydrates inhibitors in the pipelines.