With the consumption of conventional hydrocarbon reserves and advancement in drilling technology, recently there is a high interest in gas hydrates in the world. Due to lack of experience and sensitive nature of gas hydrates, drilling in gas hydrate reservoirs were considered as risky. However, recent drilling data in gas hydrates shows that successful drilling operations in gas hydrate reservoirs are possible with some special measurements such as specially designed drilling fluid and cement slurry etc. In this study, open-hole riserless drilling, drilling with riser in marine environment, logging while drilling, drilling fluid, cement and coring systems used in hydrate exploration are explained. (C) 2016 Elsevier B.V. All rights reserved.