川南页岩气区块生命周期用水核算

选取川南页岩气区块为研究对象,运用过程生命周期评估和投入产出生命周期方法核算页岩气开采生命周期的直接和间接用水量,并与美国Marcellus页岩气区块用水量进行比较。川南区块总直接用水量为22 928 m^3/井,高于Marcellus区块的总直接用水量15 320 m^3/井。从生命周期阶段来看,川南页岩气开采钻井和压裂阶段的直接用水均远大于Marcellus区块。结合水环境管理指标,自然资源禀赋条件主要决定了直接用水量的差异。川南区块总间接用水量为25 098 m^3/井,超过总直接用水量,约为Marcellus区块总间接用水量的3倍。除井场准备阶段外,其余阶段的间接用水量均大于Marcellus区块,间接用水量的差异与钻井和压裂过程的添加剂、能源使用量和全行业用水效率有关。减少川南区块页岩气开发用水量的主要途径包括提高钻井液和压裂液回用率、改善钻井和压裂添加剂使用效率、提高柴油和电力等能源利用效率和全行业用水效率。

Accounting of Life Cycle Water in South Sichuan Shale Gas Block

The shale gas block in the South Sichuan Province was selected as the research object.The process life cycle assessment(PLCA)and economic input-output life cycle assessment method(EIO-LCA)were used to calculate the direct and indirect water consumption of the shale gas extraction life cycle,with the comparison of the water consumption in US Marcellus Block.The results showed that the average direct water consumption in South Sichuan block is 22 928 m^3 per well,much higher than that of Marcellus,15 320 m^3 per well.The difference in direct water consumption is mainly due to the fracturing capacity and reservoir-forming conditions.The average indirect water consumption in South Sichuan block is 25 098 m^3 per well,which exceeds the direct water consumption and is about 3 times as much as that of Marcellus.The difference in indirect water consumption is related to the material,energy consumption and the water efficiency of the whole industry.The results showed that besides resource endowment,the future directions of water saving were mainly to improve fracturing fluid reuse rate,reduce material and energy consumption,and improve water use efficiency in various industries.