Impact of faults on fluid flow in Zechstein carbonates

众所周知，油藏内部的断层会对产量产生重大影响。在低孔隙度、脆性岩石中形成的断层可能比周围的储层具有更高的渗透率，因此可以作为流体流动的管道。另一方面，在多孔的、延展性强的岩石中形成的断层常常起到阻碍流动的作用；这些通常被称为密封断层。封闭断层的存在通常会降低石油开采的经济性，因为与没有断层分隔的油藏相比，需要更多的井来生产相同体积的石油。密封断层也可能对未来的二氧化碳储存作业产生重大影响。最近，大量的研发工作使我们在预测断层对砂岩储层流体流动的影响方面取得了重大进展。特别是砂岩中断层岩的渗透率，目前已有大量的资料。TransGen等软件工具通常使用这些值来预测断层沿线的渗透率分布，并生成可包含在流体流动模型中的输入文件，以考虑断层对石油生产的影响。然而，目前还没有类似的工具可用于评估断层对碳酸盐岩储层内流体流动的影响。这是一个重大的遗漏，因为作为石油储集层，碳酸盐岩与砂岩同等重要，甚至更重要。数据和软件工具的缺乏降低了行业优化石油生产和计划提高石油采收率（EOR）计划的能力。在未来，这种知识差距可能会降低我们评估二氧化碳储存和核废料处置场所安全性的能力。为了填补这一知识空白，本项目将：(i)建立碳酸盐岩断层岩流动特性数据库。（ii）确定断裂时对这些性质的关键控制，如应力和流变学。（三）确定已发表的断层如何影响碳酸盐岩储层流体流动的实例。（四）制定算法和工作流程，将这些结果纳入工业标准软件工具，以提高我们模拟碳酸盐岩储层中与断层有关的流体流动的能力。

It is well known that faults within petroleum reservoirs can have a significant impact on production. Faults formed in low porosity, brittle, rocks may have a higher permeability than the surrounding reservoir and therefore can act as conduits for fluid flow. On the other hand, faults formed in porous, ductile, rocks often act as barriers to flow; these are often referred to as sealing faults. The presence of sealing faults often makes petroleum production less economic because more wells are needed to produce the same volume of petroleum compared to a reservoir that is not compartmentalized by faults. Sealing faults are also likely to have a significant impact on future CO2 storage operations. A large amount of R&D has recently led to major advances in our ability to predict the impact of faults on fluid flow in sandstone reservoirs. In particular, a large amount of data now exists on the permeability of fault rocks in sandstones. These values are routinely used by software tools, such as TransGen, to predict the permeability distribution along faults and generate input files that can be included into fluid flow models to take into account the impact of faults on petroleum production. Similar tools are not, however, available for assessing the impact of faults on fluid flow within carbonate reservoirs. This represents a major omission given that carbonates are equally, if not more, important than sandstones as reservoirs for petroleum. This lack of data and software tools reduces the ability of industry to optimize petroleum production and plan enhanced oil recovery (EOR) programs. In the future, this knowledge gap may all reduce our ability to assess the safety of CO2 storage and nuclear waste disposal sites.To fill this knowledge gap this project will:(i) Build a database of the flow properties of fault rocks in carbonates.(ii) Identify the key controls on these properties such as stress and rheology at the time of faulting.(iii) Identify published examples of how faults affect fluid flow in carbonate reservoirs.(iv) Develop algorithms and workflows for incorporating these results into industry standard software tools to improve our ability to model fault-related fluid flow in carbonate reservoirs.