Study on the equivalence between gas hydrate digital rocks and hydrate rock physical models

Abstract According to the filling modes of gas hydrate in the permafrost, combined with rock physical method, two types of hydrate rock physical models are established by the method of elastic modulus model, including skeleton type hydrate rock physical model and fluid type hydrate rock physical model. Besides, based on the CT scanning images of hydrate reservoir rocks, combined with the numerical simulation method of hydrate distribution, two types of hydrate digital rock models are constructed, which correspond to the hydrate rock physical models. Firstly, time average equations are used to estimate several physical properties of hydrate rocks, the velocities of the hydrate rock are calculated on different models, in order to verify the equivalence between hydrate rock physical models and hydrate digital rock models, and compare the difference between different hydrate filling modes. Secondly, different models are appliedto the characteristics analysis of hydrate reservoir rocks. Finally, the theoretical calculation curve is compared with the data of the actual sampling point of the hydrate reservoir, which used to the recognition of hydrate filling modes. It can be seen from the results that there is a good equivalence relationship between the hydrate rock physical models and hydrate digital rock models, and the filling modes of hydrate in this area is more in accordance with the skeleton type models, which means that this method can be used to determine the hydrate filling modes in hydrate reservoirs.