北美超低渗致密油藏提高采收率技术现状

在过去的十年中，北美致密油气的开发技术日渐成熟，其中，最具代表性的技术是水力压裂和水平钻井技术的结合。然而，现有依靠天然能量的衰竭式开发只能采出超低渗储层中的少部分原油（采出程度低于10%），导致致密储层中仍存在大量剩余油。因此，非常规超低渗油藏提高采收率技术的研究日趋重要。目前，全世界90%以上的致密油产量来自美国，其开采技术在非常规致密油的开发领域具有明显优势。并且，在过去的十年间，北美的石油公司已经对针对致密低渗油藏的提高采收率（EOR）技术进行了许多现场测试。鉴于美国在非常规致密油的勘探开发中具有领先地位，重点对北美致密油资源开发中提高采收率措施的现场经验进行了总结和评价，并指出了其目前面临的主要困难和挑战。此项研究对于中国未来超低渗致密油藏提高采收率技术的发展具有指导和借鉴意义。

Enhanced Oil Recovery of Ultra-low Permeability Tight Reservoirs in North America

There are many significant breakthroughs in unconventional oil and gas development in North America in the past decade, among which is the combination of such as hydraulic fracturing and horizontal drilling. However, only a small amount of oil from unconventional reservoirs can be recovered by primary recovery, which means a large amount of oil is remaining in tight reservoirs. Therefore, it is essential to develop the enhanced oil recovery technology in unconventional reservoirs. The United States produces more than 90 percent of the world's tight oil production, and has an overwhelming advantage in unconventional tight oil exploration and production. Operators in North America have conducted several field pilots on enhanced oil recovery (EOR) technology in tight oil reservoirs with ultra-low permeability. The summary and evaluation of these field pilots in North American unconventional reservoirs are discussed. The main difficulties and challenges of the EOR development in unconventional reservoirs are also pointed out.