3-D numerical modeling of methane hydrate deposits

Within the German gas hydrate initiative SUGAR, we have developed a new tool for predicting the formation of sub-seafloor gas hydrate deposits. For this purpose, a new 2D/3D module simulating the biogenic generation of methane from organic material and the formation of gas hydrates has been added to the petroleum systems modeling software package PetroMod®. T ypically, PetroMod® simulates the thermogenic generation of multiple hydrocarbon components including oil and gas, their migration through geological strata, and finally predicts the oil and gas accumulation in suitable reservoir formations. We have extended PetroMod® to simulate gas hydrate accumulations in marine and permafrost environments by the implementation of algorithms describing (1) the physical, thermodynamic, and kinetic properties of gas hydrates; and (2) a kinetic continuum model for the microbially mediated, low temperature degradation of particulate organic carbon in sediments. Additionally, the temporal and spatial resolutions of PetroMod® were increased in order to simulate processes on time scales of hundreds of years and within decimeters of spatial extension. As a first test case for validating and improving the abilities of the new hydrate module, the petroleum systems model of the Alaska North Slope developed by IES (currently Shlumberger) and the USGS has been chosen. In this area, gas hydrates have been drilled in several wells, and a field test for hydrate production is planned for 2011/2012. The results of the simulation runs in PetroMod® predicting the thickness of the gas hydrate stability field, the generation and migration of biogenic and thermogenic methane gas, and its accumulation as gas hydrates will be shown during the conference. The predicted distribution of gas hydrates will be discussed in comparison to recent gas hydrate findings in the Alaska North Slope region