Lithofacies uncertainty modeling in a siliciclastic reservoir setting by incorporating geological contacts and seismic information

Deterministic modeling lonely provides a unique boundary layout, depending on the geological interpretation or interpolation from the hard available data. Changing the interpreter’s attitude or interpolation parameters leads to displacing the location of these borders. In contrary, probabilistic modeling of geological domains such as lithofacies is a critical aspect to providing information to take proper decision in the case of evaluation of oil reservoirs parameters, that is, applicable for quantification of uncertainty along the boundaries. These stochastic modeling manifests itself dramatically beyond this occasion. Conventional approaches of probabilistic modeling (object and pixel-based) mostly suffers from consideration of contact knowledge on the simulated domains. Plurigaussian simulation algorithm, in contrast, allows reproducing the complex transitions among the lithofacies domains and has found wide acceptance for modeling petroleum reservoirs. Stationary assumption for this framework has implications on the homogeneous characterization of the lithofacies. In this case, the proportion is assumed constant and the covariance function as a typical feature of spatial continuity depends only on the Euclidean distances between two points. But, whenever there exists a heterogeneity phenomenon in the region, this assumption does not urge model to generate the desired variability of the underlying proportion of facies over the domain. Geophysical attributes as a secondary variable in this place, plays an important role for generation of the realistic contact relationship between the simulated categories. In this paper, a hierarchical plurigaussian simulation approach is used to construct multiple realizations of lithofacies by incorporating the acoustic impedance as soft data through an oil reservoir in Iran.This research was funded by the National Elites Foundation of Iran in collaboration with research Institute Petroleum of Industry in Iran under the project number of 9265005

Predictable patterns in stacking and distribution of channelized fluvial sandbodies linked to channel mobility and avulsion process

Despite the importance of channel avulsion in constructing fluvial stratigraphy, it is unclear how contrasting avulsion processes are reflected instratigraphic-stacking patterns of channelized fluvial sandbodies, asa proxy for how riverdepocentersshifted in time and space. Using an integrated, geospatially-referenced 3D dataset that includesoutcrop, core, and LiDAR data, we identify for the first time in an outcropstudy a predictive relationship between channelized-sandbodyarchitecture, paleochannel mobility, and stratigraphic-stacking pattern. Single-story sandbodies tend to occur in vertically-stacked clusters that are capped by a multilateral sandbody, indicating an upward change from a fixed-channelsystem to a mobile-hannelsystem in each cluster.Vertical sandbody stacking in the clusters implies reoccupation of abandoned channelsafter “local” avulsion.Reoccupational avulsion may reflect channel confinement, location downstream of a nodal avulsion point that maintained its position during development of the sandbody cluster, and/or aggradation and progradation of a backwater-mediated channel downstream of a nodal avulsion point. Sandbody clusters and additional multilateral sandbodies are laterallyoffset or isolated from each other, implying compensational stackingdue to “regional” switching of a nodal avulsion point to anew, topographically-lowersite on the floodplain.The predictive links between avulsion mechanisms, channel mobility,and resultant sandbody distributions and stacking patterns shown in our findings haveimportant implications forexploringand interpreting spatio-temporal patterns of stratigraphic organizationin alluvial basins