Can low hydration heat cement prevent the decomposition of natural gas hydrate under high pressure and low temperature?

In this article, an in-house device is used to study the prevention of natural gas hydrate (NGH) decomposition performance and the mechanism of the low-heat cement for cementing. The results show that the natural gas hydrate can decompose to different degrees due to the hydration heat of the G-class oil well cement at the experimental conditions of 281.15 K & 8 MPa and 277.15 K & 6.5 MPa. Decomposition occurs within the period of hydration heat peak. The visualization window allows observing the decomposition and reduction of natural gas hydrate. The low-heat cement can effectively prevent the decomposition of natural gas hydrate at the experimental conditions of 281.15 K & 8 MPa, 277.15 K & 6.5 MPa, and 273.15 K & 4.5 MPa. The hydration heat experiment found that with the decrease in the hydration environment temperature, the hydration temperature rise appeared significantly later, the induction period was delayed into the acceleration period, the maximum of hydration temperature rise exhibited a decreasing phenomenon, and the hydration temperature rise of low hydration heat cement was far lower than that of the G-class oil well cement.