‘LOSCS’ Lateral Offset Stacked Channel Simulations: Towards geometrical modelling of turbidite elementary channels

Abstract

Turbidite hydrocarbon reservoirs are complex features, that need to be described in detail and represented as clearly as possible. The morphology and internal distribution of elementary distributary channels are dependent on depositional settings, leading to diverse arrangements at different scales. Reservoir modelling usually requires a description of sedimentary heterogeneity on a scale smaller than that given by seismic resolution. This is because seismic data only display the outside geometry of their lateral stack, i.e. a turbidite fairway. Complexes of Laterally Offset Stacked Turbidite Channels (LOSCs) also require a description based on the scales of individual channel bodies. The most common representation of channels in a fairway is by stochastic object modelling; i.e. populating the observed fairway with realistic forms representing individual channels, but with no established consistency between the individual channels. On the other hand, one essential characteristic of LOSCs is that it evolves by progressive migration laterally and/or downdip. Stochastic object modelling provides an inadequate representation of this progressive evolution, and consequently, a poor rendering of the heterogeneity distribution in the reservoir. The method we propose consists of defining a realistic succession of individual channels that can accurately build the fairway observed on seismic. ‘Realism’ is defined using criteria from the shape of individual channels, and based on the amount of displacement necessary between successive episodes. Depending on seismic resolution, the system can be constrained by one or several positions of individual channels (the most recent position of the channel is often filled with shale, therefore visible on seismic and usable as a control point). The final result is a deterministic succession of channels laterally stacked to build the seismically observed envelope. Even with no calibration, the resulting architecture respects the general ‘texture’ of the complex and provides a better simulation of flow pathways than that achieved by random object modelling.

A model of submarine channel-levee evolution based on channel trajectories: Implications for stratigraphic architecture

“…Our model accounts for lateral channel migration, incision, aggradation, channel and overbank deposits, cutoffs, and includes a simple depth-dependent facies distribution. While it shares some characteristics with existing three-dimensional models of fluvial (Cojan et al, 2005;Pyrcz and Deutsch, 2005;Pyrcz et al, 2009;Willis and Tang, 2010) and submarine channels (Pyrcz and Strebelle, 2006;Labourdette, 2008;Labourdette and Bez, 2010;McHargue et al, 2011), our model includes several important new features: (1) development of valley morphology through long-term channel erosion; (2) long-term levee deposition resulting in consistent channel-levee and innerto-outer levee relationships; and (3) existence of a realistic geomorphic surface with a single, unfilled channel form at all times. This last feature allows us to represent the model results not only in physical stratigraphic space but in a precise three-dimensional chronostratigraphic framework as well.…”

“…(1) within individual submarine channel systems, channel size variability is relatively small, (2) channels migrate in a systematic way and their placement is far from random (Labourdette, 2008;Labourdette and Bez, 2010). Starting from such observations, we have developed a three-dimensional geometric model for submarine channel-levee systems.…”

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

“…These typically use models of specific outcrops or related generic models. Such models have been used to investigate the influence of various aspects of reservoir architecture on fluid flow across a range of different reservoir types, such as fluvial connectivity (Georgsen et al 1994), understanding shallow-marine reservoirs (Kjønsvik et al 1994;Bransaeter et al 2005), the connectivity of channelized reservoirs (Larue & Hovadik 2006, 2008, the behaviour of the Ainsa deep-water reservoir analogue (Larue 2004;Labourdette 2008) and the role of clinoforms draping shales as barriers (Forster et al 2004;Howell et al 2008b;.…”

“…During field appraisal and development, planning models are used for optimizing well locations and spacing. During field production, models are built to monitor and predict performance and to plan infill wells (Labourdette 2008). Models are also built prior to any major IOR (increased oil recovery) activities to predict performance and test the economic viability of such projects (e.g.…”

Reconstruction of Channelized Systems Through a Conditioned Reverse Migration Method

“…Labourdette (2008) proposed a geometric modeling approach based on the seismic observations of a turbidite system (e.g., final stage, channel belt borders) and on the probable migration of characteristic points of the channel trajectory. The idea of Ruiu et al (2015) is to reduce the sinuosity of the channel by doing a reverse lateral migration of the channel.…”