低油价下国内非常规气与进口气竞争力对比

近年来,非常规天然气已成为我国天然气供应的重要构成之一,在低油价的新常态下,中国油气行业面临究竟是继续低效益开发国内非常规气,还是加大进口海外天然气的现实抉择。为此,基于国内典型非常规气田的开发成本现状,采用净现金流量法,开展了典型非常规气田单井经济效益评价,构建了反映单井投资、累计产量、内部收益率3大关键指标的技术经济界限图版并与进口气价格进行对比,得出不同油价下我国非常规气效益开发的最优序列。研究结果表明:(1)在当前气价、投资、产量水平下,只有致密气藏"甜点区"可实现效益开发,煤层气藏、页岩气藏的内部收益率均低于基准收益率,有待于进一步降本增效;(2)当原油价格发生变化时,若油价为40美元/桶(1桶=0.159 m~3),国产致密气相比进口LNG效益更优,可优先开发,并加大LNG进口比例;(3)若油价为50美元/桶及以上时,国产非常规气相比进口LNG效益更优,应加大开发力度,平衡好国产气与进口气的供应比例关系,以实现效益最大化。

Competitiveness comparison between domestic unconventional natural gas and imported gas in the context of low oil price

In recent years, unconventional gas has become one important portion of natural gas supply in China, so under the present low-oil-price global situation, oil and gas operators have to make a realistic choice of whether to keep on developing unconventional gas resources with low efficiency and low profit or to turn to more gas import from abroad. In view of this, based on typical dynamic and cost data from domestic unconventional gas fields, the Net Present Value (NPV) was applied to make a single-well economic evaluation of typical unconventional gas fields, and the technological and economic limit charts were made reflecting the three indexes of the investment & cumulative output per well and the internal rate of return (IRR). Then, through a comparison with the imported gas prices, the optimal development sequences under different oil price scenarios were obtained. The following findings were achieved. First, under the present level of gas price, investment and gas yield, benefits will be achieved only in the sweet point zones of tight gas fields, while lower cost and higher efficiency will be highly needed in those CBM and shale gas fields, the IRR of which is lower than the minimum acceptable rate of return (MARR). Second, if crude oil price stays at 40 USD per barrel (1 barrel equals 0.159 standard cubic metres), domestic tight sand gas should be developed primarily with the increasing imported LNG as a supplement; If the price rises to more than 50 USD per barrel, all domestic unconventional gas should be developed in the first place, and the supply balance between domestic and the imported gas will be well kept to achieve the maximum benefit.