gas hydrate - CCOP

MATHEMATICAL MODEL
The mathematical model for the STOMP-HYD simulator comprises governing conservation
equations and associated constitutive equations that describe the flow and transport of heat
and components through multiphase geologic media. In general the solved flow and transport
equations are identical across the community of numerical simulators for methane hydrate
production. STOMP-HYD, however, differs from hydrate production simulators in its use of
capillary pressure functions to calculate phase saturations. This section describes the
governing conservation equations and the calculation approach for the mobile and immobile
phases.
Governing Equations
The STOMP-HYD simulator solves five conservation equations, which can be expressed in
two forms: 1) conservation of heat and 2) conservation of component mass (i.e., H 2 O, CH 4 ,
CO 2 , and NaCl). The conservation of heat equation, expressed in differential form, states that
the time rate of change of internal energy equals the net transport of heat into the system,
according to Eqn. (2.1):
Where, the phase flux is computed via Darcy’s law, according to Eqn. (2.2), and component
diffusion is computed from molar gradients, considering molecular diffusion and hydraulic
dispersion, according to Eqn. (2.3). Only the contribution of gas phase diffusion/dispersion is
considered for the conservation of heat equation.
The conservation of component-mass equation, expressed in differential form, states that the
time rate of change of component mass equals the net transport of component mass into the
system, as shown in Eqn. (2.4):
Where, for mass transport, diffusion through all mobile phases is considered. Hydraulic
dispersion is considered only for the transport of NaCl.
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New Energy Resources in the CCOP Region - Gas Hydrates and Coalbed Methane