双层分支水平井注热海水开采海底天然气水合物经济性评价

摘要

Due to the large submarine natural gas hydrate reserves, it is meaningful to exploit these resources in a cost-effective manner. Given that the existing mining methods all have inherent lfaws respectively, a thermal seawater injection method of double-branch horizontal wells is proposed in an attempt to explore the economical, safe and feasible mining methods of natural gas hydrate. The method is based on the research result about “thermal seawater injection method of double-branch horizontal wells” from Kyuro Sasaki, Shinji Ono and others of the Energy School of Kyushu University. It is a new mining method that uses a series of advantageous technologies including seawater source heat pump, shallow-branch horizontal well drilling, and natural gas hydrate decomposition using high-temperature brine. This method fully utilizes the selective drilling and large effectively controlled area of branch horizontal wells to achieve multi-point communication in the reservoir stratum by injecting thermal seawater into double-branch horizontal wells for form“hot water cavities” and perform three-dimensional exploration of natural gas hydrate by injecting from the bottom and mining at the top. This mining method is not only safe and feasible and environmentally friendly, but also economic beneifcial. It is a positive, pragmatic and innovative attempt to achieve commercial exploitation of natural gas hydrates in the future.%开展了对天然气水合物经济、安全可行的开采方法探索，提出双层分支水平井注热海水开采法。该方法是基于日本九州大学能源学院Kyuro Sasaki和Shinji Ono等人的“双水平井注热水开采法”研究成果，利用海水源热泵加热、浅层分支水平井钻井及高温盐水分解天然气水合物等优势技术提出来的一种全新的开采方法。充分利用分支水平井的选择性钻进和有效控制面积大等特性，通过在双层分支水平井中注入热海水形成“热水腔”实现储层的多点沟通，以下注上采模式完成天然气水合物的立体开采。该开采法安全可行、环境友好，且具有较好的经济效益，是实现未来天然气水合物商业化开采的一种积极探索。