Study on natural gas hydrate prediction and prevention of gas well in Daqing oilfield

At present, the hydration formation in the well bore brings about a certain difficulty for the production and management in Daqing oilfield. The node analysis method was used to research gas hydrate prediction and prevention. The pipesim software was used to predict hydrate formation. The results showed that the formation pressure is 12-24 MPa, the I and II type hydrate will generate at 14.4-19.5 degrees centigrade in the well bore. The I type hydrate cannot generate with 0.01 m(3)/d methanol or ethylene glycol. Yet the II type hydrate cannot generate with 0.03 m(3)/d methanol or 0.02 m(3)/d ethylene glycol injected. Under the condition of Daqing oilfield gas well, the effect of ethylene glycol prevention hydrates formation is better than that of methanol at the same concentration. The total amount of methanol and ethylene glycol complex system is 0.02 m(3)/d. The complex system of 20% methanol and 80% ethylene glycol can prevent II type hydrate formation in gas well.