Optimization of production well patterns for natural gas hydrate reservoir: Referring to the results from production tests and numerical simulations

Abstract

Natural gas hydrate is a clean energy source with substantial resource potential. In contrast to conventional oil and gas, natural gas hydrate exists as a multi-phase system consisting of solids, liquids, and gases, which presents unique challenges and complicates the mechanisms of seepage and exploitation. Both domestic and international natural gas hydrate production tests typically employ a single-well production model. Although this approach has seen some success, it continues to be hindered by low production rates and short production cycles. Therefore, there is an urgent need to explore a new well network to significantly increase the production of a single well. This paper provides a comprehensive review of the latest advancements in natural gas hydrate research, including both laboratory studies and field tests. It further examines the gas production processes and development outcomes for single wells, dual wells, multi-branch wells, and multi-well systems under conditions of depressurization, thermal injection, and CO₂ replacement. On this basis, well types and well networks suitable for commercial exploitation of natural gas hydrate were explored, and the technical direction of natural gas hydrate development was proposed. The study shows that fully exploiting the flexibility of complex structural wells and designing a well network compatible with the reservoir is the key to improving production from a single well. Moreover, multi-well joint exploitation is identified as an effective strategy for achieving large-scale, efficient development of natural gas hydrate.