Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, TX, United States of America.
Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, TX, United States of America.
Sci Total Environ. 2020 May 15;717:137085. doi: 10.1016/j.scitotenv.2020.137085. Epub 2020 Feb 3.
There is increasing interest in beneficial uses of large volumes of wastewater co-produced with oil and gas extraction (produced water, PW) because of water scarcity, potential subsurface disposal limitations, and regional linkages to induced seismicity. Here we quantified PW volumes relative to water demand in different sectors and PW quality relative to treatment and reuse options for the major U.S. shale oil and gas plays. PW volumes from these plays totaled ~600 billion liters (BL, 160 billion gallons, Bgal) in 2017. One year of PW is equal to ~60% of one day of freshwater use in the U.S. For these plays, the total irrigation demand exceeded PW volumes by ~5× whereas municipal demand exceeded PW by ~2×. If PW is reused for hydraulic fracturing (HF) within the energy sector, there would be no excess PW in about half of the plays because HF water demand exceeds PW volumes in those plays. PW quality can be highly saline with median total dissolved solids up to 255 g/L in the Bakken play, ~7× seawater. Intensive water treatment required for PW from most unconventional plays would further reduce PW volumes by at least 2×. Desalination would also result in large volumes of salt concentrates, equivalent to ~3000 Olympic swimming pools in the Permian Delaware Basin in 2017. While water demands outside the energy sector could accommodate PW volumes, much lower PW volumes relative to water demand in most regions would not substantially alleviate water scarcity. However, large projected PW volumes relative to HF water demand over the life of the play in the Permian Delaware Basin may provide a substantial new water source for beneficial use in the future. Large knowledge gaps in PW quality, lack of appropriate regulations, and economic factors currently preclude beneficial uses outside the energy sector in most regions.
由于水资源短缺、潜在的地下处置限制以及与诱发地震的区域联系，人们对与石油和天然气开采（生产水，PW）一起产生的大量废水的有益利用越来越感兴趣。在这里，我们量化了与不同部门的水需求相比，与美国主要页岩油和天然气开采的处理和再利用选择相比，PW 的体积和质量。这些开采中的 PW 总量在 2017 年达到了约 6000 亿升（BL，1600 亿加仑，Bgal）。一年的 PW 相当于美国一天淡水使用量的约 60%。对于这些开采，总灌溉需求超过 PW 体积约 5 倍，而市政需求超过 PW 约 2 倍。如果 PW 在能源部门内被重新用于水力压裂（HF），那么在大约一半的开采中不会有多余的 PW，因为 HF 水需求在这些开采中超过了 PW 体积。PW 质量可能高度咸化，在 Bakken 开采中总溶解固体中位数高达 255g/L，约为海水的 7 倍。大多数非常规开采的 PW 需要进行强化水处理，这将使 PW 体积减少至少 2 倍。海水淡化也会导致大量的盐浓缩物，在 2017 年的二叠纪 Delaware 盆地中，相当于约 3000 个奥林匹克游泳池。尽管能源部门以外的用水需求可以容纳 PW 体积，但与大多数地区的水需求相比，PW 体积低得多不会大大缓解水资源短缺。然而，在二叠纪 Delaware 盆地的开采生命周期中，相对于 HF 水需求的 PW 预测量巨大，可能为未来的有益利用提供大量新的水源。目前，PW 质量的大量知识空白、缺乏适当的法规以及经济因素，在大多数地区都排除了能源部门以外的有益利用。
