Data capture for multiscale modelling of the Lourinhã Formation, Lusitanian Basin, Portugal: an outcrop analogue for the Statfjord Group, Norwegian North Sea

Abstract

Current recovery from the Statfjord Group in the majority of the fields on the Tampen Spur is less than 50%. A contributing factor to this is an incomplete understanding of multiscale heterogeneities, their distributions within a range of fluvial geobodies and their lateral extent and morphology in inter-well areas. Sedimentary heterogeneities have been modelled, together with petrophysical parameters, at a variety of scales. The modelled properties at a given scale were upscaled to the next level of heterogeneity, thus better honouring effective property values. The use of outcrop analogues is still a key tool for understanding facies relationships and the stratigraphic development of subsurface hydrocarbon-bearing reservoirs. The Lourinhã Formation, Portugal, was used as an analogue to collect both qualitative and quantitative data consistently following a three-phase workflow to capture data at various scales of heterogeneity. Traditional field data collection techniques have been supplemented with the collection of LiDAR data. A digital workflow utilizing interlinked datasets facilitates rapid data analysis and better data visualization with results that are more easily utilized in multiscale modelling studies. These scaled models were used to increase our understanding of the effect on flow of lithofacies and facies association distributions together with internal architectural elements and heterogeneities.

The application of outcrop analogues in geological modelling: a review, present status and future outlook

“…2001), all of which are used for conditioning objectbased models. Quantification of the geometry and dimensions of the sedimentary building blocks (also referred to as architectural elements or genetic units) that comprise the reservoir is typically undertaken with a stratigraphic framework that defines the larger-scale architecture or stacking pattern of the elements (Keogh et al 2014). The product of this type of study consists of statistical descriptions of attributes, such as channel sandstone-body width -thickness relationships.…”

“…At this stage, the majority of data are coming from the oil field rather from outcrop analogues, although it may be possible to incorporate data from nearby analogue fields. Outcrop analogues may, however, provide soft data on the breadth of the permeability range that is typically underestimated in the limited subsurface dataset, and also on the permeability structure that might exist to bridge the gap between core plug and cell in the model Keogh et al 2014;Nordahl et al 2014). …”

“…Multi-scale modelling is a specific kind of upscaling in which the elements that control fluid flow (laminae, bedforms, facies, facies associations) are specifically modelled at the representative elemental volume (REV) scale Ringrose et al 2008). This part of the workflow is not commonly used but is extremely valuable in reservoirs that are heterolithic at a wide range of scales (Keogh et al 2007(Keogh et al , 2014Nordahl et al 2014).…”

“…In complex heterolithic reservoirs there may be several scales of modelling, with the results from a fine-scale set of models being used to condition the inputs for the next level of model (Elfenbein et al 2005;Ringrose et al 2005). These small-scale models may be conditioned from process-based models (Nordahl et al 2014) or from studies of outcrops (Jackson et al 2003) or from a combination (Keogh et al 2014). …”

“…The procedure applied for determination of fluvial sandstone-body size needs to be well documented in order to avoid mixing of body types and of dimensions (Fielding & Crane 1987;Gibling 2006;Keogh et al 2014). It also needs to be coupled to a careful definition of what has been measured; for example, single or composite point bars, or single-or multistorey channelized sheets.…”