Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin , 10100 Burnet Road, Austin, Texas 78758, United States.
Environ Sci Technol. 2017 Sep 19;51(18):10903-10912. doi: 10.1021/acs.est.7b02185. Epub 2017 Sep 6.
The Permian Basin is being transformed by the "shale revolution" from a major conventional play to the world's largest unconventional play, but water management is critical in this semiarid region. Here we explore evolving issues associated with produced water (PW) management and hydraulic fracturing water demands based on detailed well-by-well analyses. Our results show that although conventional wells produce ∼13 times more water than oil (PW to oil ratio, PWOR = 13), this produced water has been mostly injected back into pressure-depleted oil-producing reservoirs for enhanced oil recovery. Unconventional horizontal wells use large volumes of water for hydraulic fracturing that increased by a factor of ∼10-16 per well and ∼7-10 if normalized by lateral well length (2008-2015). Although unconventional wells have a much lower PWOR of 3 versus 13 from conventional wells, this PW cannot be reinjected into the shale reservoirs but is disposed into nonproducing geologic intervals that could result in overpressuring and induced seismicity. The potential for PW reuse from unconventional wells is high because PW volumes can support hydraulic fracturing water demand based on 2014 data. Reuse of PW with minimal treatment (clean brine) can partially mitigate PW injection concerns while reducing water demand for hydraulic fracturing.
二叠纪盆地正在经历“页岩革命”，从主要的常规油田转变为世界上最大的非常规油田，但在这个半干旱地区，水资源管理至关重要。在这里，我们根据详细的逐井分析，探讨了与采出水（PW）管理和水力压裂水需求相关的不断变化的问题。研究结果表明，尽管常规油井生产的水量比石油多 13 倍（PW 与油比，PWOR = 13），但这些采出水大部分已被重新注入到压力枯竭的油藏中，以提高石油采收率。非常规水平井使用大量的水进行水力压裂，每口井的用水量增加了约 10-16 倍，如果按水平井长度归一化，则增加了 7-10 倍（2008-2015 年）。尽管非常规油井的 PWOR 比常规油井低 3 比 13，但这些 PW 不能再注入页岩储层，而是被排放到非生产地质层段，这可能导致超压和诱发地震。非常规油井 PW 再利用的潜力很大，因为根据 2014 年的数据，PW 量可以支持水力压裂水的需求。PW 的再利用（清洁盐水）只需进行最小的处理，就可以部分缓解 PW 注入的担忧，同时减少水力压裂的水需求。
