Generation and distribution of thermogenic natural gas hydrates in submarine sediments

With an one-dimensional equipment designed by China University of Petroleum,the simulation of natural gas hydrate generation was carried out using conventional thermogenic natural gas as source and submarine sediment as porous medium.Resistivity method was applied to analyze the generation and distribution of natural gas hydrate in sediment.The results showed that resistivity varied between different positions of sediment.In the middle and lower position,resistivity first increased and then became stable.While in the middle and upper position,resistivity changed like zigzag,that was,decreasing,increasing (or stable),decreasing,increasing and stable.The changes of resistivity indicated the generation and distribution of natural gas hydrate in different positions.The natural gas hydrates in the middle and lower positions had come into being while those in the middle and upper positions were still during the induction and nucleation stages.Influenced by temperature gradient,natural gas hydrates generated slowly and scattered.If gas supplied sufficiently,natural gas hydrates might generate massively in the middle and upper positions.Finally,a hydrate generation and distribution model was established based on the above-mentioned analyses.