Impact of faults on fluid flow in Zechstein carbonates

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.