DEVELOPMENT OF A PETREL PLUG-IN FOR ESTIMATING GAS HYDRATE, FREE GAS CONCENTRATION AND GAS HYDRATE STABILITY ZONE THICKNESS AT THE STOREGGA SLIDE ON THE MID-NORWEGIAN MARGIN

Abstract

Gas hydrates are naturally occurring nonstoichiometric crystalline solids comprised of entrapped guest molecules in hydrogen bonded water lattice. They are stable beneath most of the world's - continental margins and deep inland seas and also in permafrost layers of Artic. Gas hydrates can - be potential source of energy in future. Large amount of methane gas is entrapped in form gas hydrates in the world. Their dissociation can cause dramatic changes in global climate and sub-sea instabilities. For these few reasons, gas hydrate studies are crucial in present time. In this thesis I quantified gas hydrates and underlying free gas in the Storegga Slide on the mid-Norwegian margin using effective medium theory. Gas hydrates are modeled in the sediment as a pore fluid component, a sediment frame component and as an elastic cement at grain contacts. On an average the gas hydrate concentration in the Storegga region is 5% in the pore space, with peak concentration of 10-12% at some depths. The free gas concentration beneath the BSR is on an average 0.5%, with peak concentration of 1-2% assuming homogeneous distribution. I have also a - developed a Petrel plugin for estimating the thickness of the hydrate stability zone in the Storegga region using 3-phase equilibrium equations with sub-bottom temperature profile. The thickness of the I-ISZ estimated is in the range of 200-240m.