Using similarity theory to design natural gas hydrate experimental model

• We summarized a mathematical model for hydrate exploitation from HydrateResSim.
• We defined two kinds of characteristic time based on the two controlling mechanisms.
• We derived 73 similarity numbers for gas hydrate experimental model design.
• We put forward two schemes for the design of gas hydrate experimental model.

Experimental simulation is an important approach to study the gas hydrate dissociation mechanism, and similarity theory is an effective tool for the design of experimental model. Based on hydrate kinetic reaction model in HydrateResSim, seventy-three similarity numbers are derived by means of inspectional analysis and dimensionless analysis. Gas production from the natural gas hydrate reservoir is controlled by two mechanisms, namely dissociation-controlled mechanism and flow-controlled mechanism. Two groups of schemes are put forward for the design of experimental model of natural gas hydrate according to these two mechanisms respectively: for flow-controlled hydrate reservoir the scale of injection rate of heat and water, and parameters associated with size is the same with that of length, the scale of time is the square of length scale; for dissociation-controlled hydrate reservoir, the scale of parameters associated with size is the same with that of length, the scale of absolute permeability is 4/3 times square of length scale, the scale of time is 2/3 times square of length scale, the scale of injection rate of heat and water is 7/3 times square of length scale.