Downloaded from http://sp.lyellcollection.org/ by guest on October 1, 2021 Fundamental controls on fluid flow in carbonates: current workflows to emerging technologies SUSAN M. AGAR1,2* & SEBASTIAN GEIGER3 1ExxonMobil Upstream Research Company, PO Box 2189, Houston, TX 77252-2189, USA 2Present address: Aramco Research Center, 16300 Park Row, Houston, TX 77084, USA 3Institute of Petroleum Engineering, Heriot Watt University, Edinburgh EH14 4AS, UK *Corresponding author (e-mail: [email protected]) Abstract: The introduction reviews topics relevant to the fundamental controls on fluid flow in carbonate reservoirs and to the prediction of reservoir performance. The review provides research and industry contexts for papers in this volume only. A discussion of global context and frame- works emphasizes the value yet to be captured from compare and contrast studies. Multidisciplin- ary efforts highlight the importance of greater integration of sedimentology, diagenesis and structural geology. Developments in analytical and experimental methods, stimulated by advances in the materials sciences, support new insights into fundamental (pore-scale) processes in carbon- ate rocks. Subsurface imaging methods relevant to the delineation of heterogeneities in carbonates highlight techniques that serve to decrease the gap between seismically resolvable features and well-scale measurements. Methods to fuse geological information across scales are advancing through multiscale integration and proxies. A surge in computational power over the last two decades has been accompanied by developments in computational methods and algorithms. Devel- opments related to visualization and data interaction support stronger geoscience–engineering col- laborations. High-resolution and real-time monitoring of the subsurface are driving novel sensing capabilities and growing interest in data mining and analytics. Together, these offer an exciting opportunity to learn more about the fundamental fluid-flow processes in carbonate reservoirs at the interwell scale. This Special Publication grew from numerous study or technology development. While we recog- discussions related to a joint AAPG–SPE–SEG nize that these papers may lack the scientific and Hedberg Conference in July 2012 at Saint-Cyr sur technical rigour of a peer-reviewed manuscript, Mer, France (Agar et al. 2013), and manuscripts we feel that their inclusion is justified to represent were submitted 12–18 months after the conference. evolving frontiers in fields that are relevant to car- While these papers represent only a small pro- bonate reservoirs. Related and complementary per- portion of many strong conference contributions, spectives can be found in Geological Society they span several active research areas related to Special Publications and related journals (e.g. van flow prediction in carbonate reservoirs. Here, we Buchem et al. 2010; Hollis 2011; Garland et al. do not attempt a comprehensive review of all 2012; Agar & Hampson 2014). research areas related to carbonate reservoirs but At a time when unconventional reservoirs are discuss the themes represented by the papers in attracting much attention, discussions at the Hed- this volume in an industry context, considering the berg Conference reinforced that there remains much broad challenges addressed as well as the relevant exciting and important research to pursue in the advances. Much of the science and technology realm of carbonates. Some of the most significant discussed here can also be applied to other conven- advances are now emerging from a growth in multi- tional and unconventional reservoir types but our disciplinary research efforts (and, perhaps, a shift in primary aim is to highlight recent applications in the population of geoscientists to develop more the domain of carbonate reservoirs in a manner hybridized skill sets). As history shows, however, that is useful to non-specialists. To capture recent new knowledge to support efficient production from developments from industry as well as academia, carbonate reservoirs is likely to emerge from inter- we include references to extended abstracts from actions not only between different geoscience dis- industry conferences. In many cases, these publi- ciplines but at the interfaces with other fields, such cations are likely to be the only record of a case as materials science, fundamental physics and From:Agar,S.M.&Geiger, S. (eds) 2015. Fundamental Controls on Fluid Flow in Carbonates: Current Workflows to Emerging Technologies. Geological Society, London, Special Publications, 406, 1–59. First published online November 12, 2014, http://dx.doi.org/10.1144/SP406.18 # The Geological Society of London 2015. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics Downloaded from http://sp.lyellcollection.org/ by guest on October 1, 2021 2 S. M. AGAR & S. GEIGER chemistry, biotechnology, applied mathematics, and influence ‘styles’ of flow and recovery behaviours computational sciences. For this reason, scientists (flow/recovery types) for given reservoir con- from fields outside the traditional domains of geo- ditions, fluid types and well scenarios. Knowledge science were invited to the Hedberg Conference of the frameworks and evolutionary patterns that with a view to discussing and formulating novel give rise to distinct geological combinations can joint ventures. To reinforce the multidisciplinary provide early insights into the nature of distinct approach, this introduction is organized to reflect flow domains in the subsurface. Static and thematic areas that cut across multiple disciplines dynamic domains defined by separate model com- (Table 1). Topics covered in this volume include ponents can be radically different from those geophysics, structural geology, pore-scale pro- defined by a knowledge of: (a) the combined cesses, reactive transport modelling, geological impacts of geological elements on flow in a given modelling visualization and reservoir simulation. region v. their effects modelled separately and Accordingly, we start with examples that illustrate coupled across different grids; and (b) the signifi- the value of global context and multidisciplinary cance of knowing the relative impacts of geological studies. We then discuss advances in analytical elements on flow at different scales (in a given com- and experimental methods. This section is followed bination) and to determine which ones matter. There by a discussion of advances in subsurface imaging is certainly value in individual studies, such as and sensing methods. We then discuss inputs into in-depth investigations of carbonate fault zones models and the representation of multiscale data (Ferrill et al. 2011), studies of mechanisms, environ- as a challenge common to multiple geoscience dis- ment and timing related to fracture populations ciplines. A discussion of modelling techniques is (Amrouch et al. 2010; Jeanne et al. 2012), and con- then followed by a discussion of monitoring on pro- straints on reservoir architecture, physical proper- duction timescales or in real time. ties and fluid systems (Hausegger et al. 2010; Wolf et al. 2012) that yield valuable insights into processes and location-specific factors. Similarly, the last few years have seen a continuing publication Global context and frameworks of diagenetic studies in outcrops (Lo´pez-Horgue Background and challenges et al. 2010; Maliva et al. 2011; Palermo et al. 2012) as well as in the subsurface (Morad et al. One of the key challenges for translating academic 2012; Machel 2010). However, as recognized at geoscience research into industry applications is the Hedberg Conference, advances in these scienti- the need to place information and insights from fic areas could benefit substantially from broader, independent studies into a relevant framework or coordinated community efforts in a manner similar global context. For decades, geoscientists have to large integrated studies such as the Genome Pro- captured detailed data and interpretations from out- ject (Abecasis et al. 2010). crops, complemented by various theoretical, ana- Comparisons of myriad investigations per- lytical and modelling studies. But much of this formed independently on local outcrops can, in the work remains untapped by industry because it has right circumstances, offer insights far beyond those yet to be integrated into a form that provides gained through isolated studies. Given the chal- readily available, generic insights for subsurface lenges of (geological) model validation based on scenarios. While carbonate sedimentology and stra- limited access to subsurface data, regional-scale tigraphy have been developed in local, regional and insights can strengthen capabilities to link outcrop global contexts (Insalaco et al. 2000; Markello observations to inferences for the subsurface. Such et al. 2008; Garland et al. 2012), greater integration approaches can strengthen early reservoir distri- of this information into a post-depositional frame- bution and quality predictions during exploration work offers further uplift. We believe that there phases, and, together with production data, may remain significant opportunities to develop similar offer paradigm shifts for the evaluation of carbon- frameworks for diagenesis and deformation. By ate reservoirs. Comparative studies can further pro- global context, we do not simply mean ‘tectonic mote the identification of processes or associations setting’ or ‘depositional environment’ but, rather, common to given geological settings and/or his- a more sophisticated