Distribution and resource evaluation of natural gas hydrate in South China sea by combing phase equilibrium mechanism and volumetric method

China Geological Survey conducted the second trial production of natural gas hydrate (NGH) in the Shenhu Area in South China Sea (SCS) from 2019 to 2020. Compared with the first trial production in 2017, the second trial showed significantly increased daily gas production and total gas production, and removed some technical obstacles for large-scale NGH resource developments in the SCS. However, current NGH resource evaluation in the SCS is still at the stage of prospective gas content assessment, which is unable to guide further NGH exploration and development. This study utilized the hydrate phase balance to delineate the NGH distribution range and effective thickness and volumetric method to evaluate NGH resource. Based on the latest exploration and production data from the Shenhu Area, Monte Carlo simulation was performed to calculate the NGH resource amount with different probabilities. By assuming a 50% cumulative probability, the in-situ NGH resources in the SCS was estimated to be 11.7 x 10(12) m(3) and the recoverable NGH resources was 2.8 x 10(12) m(3). These results will provide a more reliable resource basis for China to formulate comprehensive development strategies for oil and gas exploration in the SCS. (C) 2021 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.