深海天然气及其水合物开发模式与钻采技术探讨

中国南海的石油天然气资源十分丰富,但其大多数都埋藏于深水区,油气勘探开发工作面临着许多难题和挑战。历经多年的探索与实践,我国海洋油气钻探工程已经实现了从浅水（水深300 m以内）到超深水（水深超过1 500 m）的跨越,并在南海发现了丰富的天然气与海域天然气水合物（以下简称水合物）资源,亟待进行安全高效开发,因而对相应的天然气及其水合物高效开发模式与技术支撑体系提出了迫切的需求。为此,针对深海天然气及其水合物安全高效开发的重大课题,提出了适用于常规天然气的“水平井或复杂结构井浮式钻完井+水下钻采系统+浮式生产、集输与浮式液化天然气生产储卸装置（FLNG）处理系统+船运外输”的开发模式及其技术支撑体系,以及适用于非常规天然气——海域天然气水合物的“水平井或复杂结构井浮式钻完井+水合物原位分解开采+水下或浮式生产与集输处理系统+管道或船运外输”的开发模式及其技术支撑体系;论述了大位移井、“U”形井等先进井型的开发模式及其适用的海洋地质环境,并给出了“U”形井的连通控制模型;此外,还介绍了与深水钻井力学和设计控制技术相关的研究进展。结论认为,建立先进适用的工程模式及其技术支撑体系,寻求实现“地质—工程—市场”一体化的解决方案,同时加强相关的信息化与智能化建设,是深海天然气及其水合物安全高效开发的关键之所在。

Discussin on development modes and engineering techniques for deepwater natural gas and its hydrates

There are rich oil and gas resources in the South China Sea, most of which are however located in deepwater areas, so the exploration and development of such resources are faced with a lot of technical challenges. In China, a great leap has been made in offshore drilling over the past years from shallow (within 300 m) to ultra deep water (more than 1500 m). On this basis, a lot of natural gas and its hydrates have been explored from the deepwater areas in the South China Sea, which urgently need to be exploited safely and efficiently. Therefore, it is useful to probe the corresponding efficient development modes and their technology supporting systems to meet such great urgent needs. In this regard, we first presented the development modes and their technology supporting systems for the exploitation of deepwater natural gas and its hydrates, such as "floating drilling operations for horizontal or complex well engineering, subsea drilling & production system, floating production and FLNG processing system, and transportation by shipping" for conventional natural gas, and "floating drilling operations for horizontal or complex well engineering, exploitation of the natural gas hydrates decomposed in situ, subsea or floating production and gathering processing system, and transportation by the pipelines or shipping" for natural gas hydrates. Moreover, we put forward such development modes as extended-reach wells or U type wells and their applicative oceanic & geological environments. In addition, we introduced a connection control model of U type wells and some research progresses in deepwater drilling mechanics & control techniques. It is concluded that the key to the safe and efficient development of deepwater natural gas and its hydrates is to establish an advanced and applicable engineering model and its technical support system, to seek for the integrated solution of "geology–engineering–marketing", and to strengthen the relevant construction of information and intelligence.