An integrated prediction model of hydrate blockage formation in deep-water gas wells

Hydrate formation and deposition in pipelines easily cause blockage in deep-water oil and gas development. Current studies on hydrate blockage in the wellbore of deep-water gas wells are dispersed. In this study, considering the variations in temperature and pressure, and the characteristics of hydrate behaviors, an integrated prediction model for hydrate blockage formation in deep-water gas wells was developed. The model results calculated using the model were in good agreement with the laboratory data for the flow loop and the field-measured data. Using the integrated model, the distribution of the hydrate stability region and the laws of the hydrate layer growth in the wellbore of deep-water gas wells can be accurately predicted, which are basis for assessing the risk of hydrate blockage. Moreover, the hydrates deposited on the inner wall of the tube are distributed non-uniformly. With an increase in the time or decrease in the inhibitor concentration, the risk of hydrate blockage increases. Based on the proposed model, a method for the prevention of hydrate blockage, is developed based on the safe operation window during deep-water gas well testing. Further, a new hydrate blockage prevention method that involves changing the testing schedule is discussed in this paper. These provide theoretical references for hydrate blockage prevention in deep-water gas well testing. (C) 2019 Elsevier Ltd. All rights reserved.