海域天然气水合物监测井技术进展与挑战

海域天然气水合物是一种极具潜力的可替代清洁能源,但开采难度大、容易导致地质灾害,因此在开发过程中对水合物储层的监测不仅能为开发方案的动态优化提供基础数据支持,而且对于评价开发过程对环境的影响尤为重要。监测井可以对水合物储层进行原位监测,是一项关键技术,但应用于海域水合物时目前可以采用的地球物理监测仪器非常有限。结合中国神狐海域水合物储层为开发难度高的低渗透率黏土质粉砂的现实,需要研发更低功耗、更高精度的长期原位温度压力监测仪器,同时需要积极开发新的监测技术,例如可以尝试在监测井中加入示踪剂指示来自监测井的流体运移,构成生产井之外水合物分解的直接证据,从而提供水合物分解范围的科学依据。

Technological Progresses and Challenges of Marine Natural Gas Hydrate Monitoring Well

Huge amount of marine natural gas hydrates is a highly promising alternative clean energy source. However, due to its difficulty in exploitation and easy to cause geological disasters, the monitoring of the hydrate reservoir during the development process not only provides fundamental data to support the dynamic optimization of the development plan, but also plays an important role in evaluating the environmental impact of the development process. The monitoring well can deploy kinds of detectors to monitor in-situ hydrate reservoir parameters, and thus is a key monitoring technology used in natural gas hydrate production. But the monitoring well for marine gas hydrate in deep water is subject to limited geophysical monitoring instruments. Combining with the fact that the characteristic lithology of hydrate reservoir in Shenhu area of the South China Sea is low permeability clayey silt, the high development difficulty requests developing long-term in-situ temperature and pressure monitoring instruments with lower power consumption and higher measurement accuracy. At the same time, new monitoring technologies need to be actively developed. For example, it can be attempted to add tracers to the monitoring well to indicate the fluid migration from the monitoring well to the production well, which is the direct evidence of hydrate dissociation outside of the production well, thus providing a scientific basis for the extent of hydrate dissociation.