Gas Field Production Of Natural Gas Hydrate Prevention And Treatment Of Experimental Research And Forecasting

Hydrate can be formed by natural gas flowing in the pipelines, borehole and formation porous media, which does harm to the hydrocarbon production and its storage and transportation. Therefore, the prevention and eliminate of gas hydrate is the big problem that has puzzled production for a long time. Correctly surveying and determining the generating conditions of gas hydrate, screening and evaluating the effect of inhibitor, and building the reasonable prediction model which predicts the critical conditions of gas hydrate generation, these researches above can provide the technical basis for the prevention and elimination of gas hydrate.On the basis of the researches on the generating conditions and mechanism of gas hydrate, using the sapphire hydrate generator, this essay made the measurements of the gas hydrate generating conditions on gas sample from Daniudi gas field, and determined the properly the using concentration, then found relatively economic formula of gas hydrate inhibitor. Considering that there were many factors in the field water sample that affected the effect of inhibitor, so in experiments we approached the compatibility among foaming agents used widely in gas field production, electrolytes in gas condensate and formation water and inhibitors. Up to now the literature reports on this aspect have not been found.In the gas field production, the salinity of formation water is usually very high, which have the certain inhibiting effect on the generation of gas hydrate. The reports on the predictive model of hydrate generation after the alcohol inhibitor is added to electrolytic water are extremely less. Therefore, building hydrate predictive model suitable to the commingled system of alcohol and brine water is badly in need.In order to precisely predict the generating conditions of hydrate, this essay made the comparison among the available predictive models and state equations, and selected the Chen&Guo model as the basic model for the prediction. Taking advantage of mixture rules on the basis of local constituent concept, we improved the PT state equation to make the model more suitable to predict the system containing the polar inhibitors. The Debye-Huckel correction having remote effect is added to PT state equation to satisfy the prediction when generating system contains electrolytes. We routinized the theory above using VB compiler language and compiled the program that can predict the generations of gas hydrate in the alcohol and brine commingled system and tested the correction of this program.Through investing and researching and summarizing the relevant materials, analyzing the experimental phenomena and data, added to the thoughts during the process of building the model and the understanding in investigating the Daniudi gas field, this essay summarized the available methods of preventing and eliminating the hydrate, then proposed the practical method used in field.