美国页岩气地面集输工艺技术现状及启示

为了促进中国页岩气资源能的规模化与高效低成本开发,根据页岩气具有压力和产能衰减速率快、开采寿命长、进入增压开采周期短、气井初期产出水量大等显著区别于常规天然气的开发与井口物性特征,分析了页岩气地面工程规划设计的难点在于:①地面工程建设需同地下资源条件相匹配;②地面集输系统设计规模不易确定;③地面集输管网与站场布置较难确定;④地面集输工程在设计初期需要考虑增压开采问题;⑤地面工艺需标准化、模块化设计;⑥地面工程设计需要考虑水处理系统的影响。以美国典型的Barnett和Marcellus页岩气田为例,对目前国外页岩气地面集输系统的总体工艺、井场工艺、处理站工艺、集输管网布置形式、产出水处理等工艺技术现状进行了系统总结,并讨论了美国页岩气地面集输工艺在我国的适应性问题,提出了中国页岩气地面工程规划设计的技术思路与建议,以期为中国页岩气资源的规模化与高效低成本开发提供指导和借鉴。

The state of the art of the surface gathering and transportation technologies in US shale gas fields and its enlightenment to China

Compared to the conventional natural gas development, commercial shale gas production will have to meet with particular challenges such as high rates of shale formation pressure drop and deliverability decline, a long service life of shale gas production wells, a short exploitation cycle of pressure boost shale gas recovery, a high yield of water production at the initial stage of a shale gas well, and so on. Accordingly, the planning and design of surface engineering in a shale gas field will also have to face up with the following difficulties. First, the ground surface engineering planning and design should match well with the underground shale gas resources conditions. Second, a ground surface engineering project design scale is not easy to determine. Third, a layout of ground gathering and transmission lines and stations is quite difficult to decide upon. Fourth, the pressure boost shale gas recovery should be considered at the preliminary design phase. Fifth, ground surface flow processes should be managed and operated under a standardized and modular program. Sixth, waste water treatment should be also taken into account in design. Taking the classical Barnett and Marcellus shale gas fields as cases of studies, we summarized and analyzed the state of the art technical process of a ground surface gathering and transmission system, in terms of well site processing facilities, infield and central processing facilities, gathering and transportation pipeline layout forms as well as water treatment technologies. In addition to the discussion on the adaptability of the US shale gas experience in China, we also presented some proposals on how to make our optimal planning and design of the surface gathering system in shale gas fields in China. This study provides a valuable reference for the high efficient and low cost development of shale gas fields in China.