**4. Conclusions**

In this work, a new low-heat cement slurry system incorporating prepared phase change microcapsules (MPCM-1) was developed for cementing in natural gas hydratebearing sediment. The following conclusions can be drawn:


This work not only provides a comprehensive and intuitive proof of the feasibility of the application of MPCM-doped low-temperature cement slurry in hydrate sediment cementing, but also provides a new idea for inhibiting the formation of temperature cracks in mass concrete in civil engineering.

**Author Contributions:** Conceptualization, Writing—Original draft preparation, Methodology: G.Y. Project administration: T.L. Project administration: H.Z. Validation: Z.Z. Visualization: Y.F. Conceptualization, Data Curation: E.L. Writing—Review and Editing: V.M. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was financed by the National Key Research and Development Program of China [Grant No. 2016YFE0204300] and the National Natural Science Foundation of China [Grant No. 42072343].

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The study did not report any data.

**Conflicts of Interest:** The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
