An analysis of the key safety technologies for natural gas hydrate exploitation

Abstract

Natural Gas Hydrate (NGH) is a high combustion efficiency clean energy and its reserve is twice as that of natural gas and petroleum, so NGH is the potential resource which could overcome the increasing energy assumption. One of the essential aspects during the exploitation of NGH is to avoid risk, and here in this work, we summarized the relevant management experience to study the critical safety risk in the exploitation of natural gas hydrate. The problems that must be resolved during NGH exploitation were identified through the research on the comparison of the characteristics of conventional gas hydrate mining methods and potential drilling engineering risks and stratum damages in the processes of exploitation. Combined with typical case analysis of gas hydrate mining, it is concluded that the key for safe NGH exploitation is the changes of stratum stress caused by hydrate decomposition; and all safety management experiences should be based on steady drilling and reasonable exploitation to prevent environment, equipment, persons and other aspects damages from layering and stress changes.

Numerical simulations of depressurization‐induced gas production from hydrate reservoirs at site GMGS3‐W19 with different free gas saturations in the northern South China Sea

“…5 The percentages of the above four types of reservoirs in nature are expected to be 14%, 5%, 6%, and 75%, respectively. 6 At present, Class 4, representing the largest content, is hard to be a candidate for gas production because of its dispersed distribution. 7 Among the other three classes, Class 1 hydrate accumulations are regarded as the most promising targets since the proximity to the hydration equilibrium at the hydrate-gas interface is favorable to gas recovery.…”

Investigation of the dissipative structures following microseismic diffusion during hydraulic fracturing of methane-hydrate-bearing sand

“…That is why specialists are searching for new innovative technologies to exploit gas hydrate deposits. Sasaki et al [5] presented a system of hot water injection with a pair of horizontal wells to exploit the NGH. The technology of hot water cyclic steam stimulation with a single well that has been traditionally used to improve the recovery effect in a superheavy oil reservoir [6] proved to be effective for NGH production augmentation.…”

Prevention of Seabed Subsidence of Class-1 Gas Hydrate Deposits via CO2-EGR: A Numerical Study with Coupled Geomechanics-Hydrate Reaction-Multiphase Fluid Flow Model

“…The weak structure of these reservoir rocks may lead to serious formation damage and cap rock failure during the gas extraction and hydrate dissociation processes. The risk of geological hazards that may occur during the hydrate production process must be avoided [13]. Hydrate dissociation that occurs in the reservoir releases both free gas and water, thereby influences the pore pressure.…”