Porosity prediction from seismic inversion of a similarity attribute based on a pseudo-forward equation (PFE): a case study from the North Sea Basin, Netherlands

Abstract

The objective of this work is to implement a pseudo-forward equation which is called PFE to transform data (similarity attribute) to model parameters (porosity) in a gas reservoir in the F3 block of North Sea. This equation which is an experimental model has unknown constants in its structure; hence, a least square solution is applied to find the best constants. The results derived from solved equations show that the errors on measured data are mapped into the errors of estimated constants; hence, Tikhonov regularization is used to improve the estimated parameters. The results are compared with a conventional method such as cross plotting between acoustic impedance and porosity values to validate the PFE model. When the testing dataset in sand units was used, the correlation coefficient between two variables (actual and predicted values) was obtained as 0.720 and 0.476 for PFE model and cross-plotting analysis, respectively. Therefore, the testing dataset validates relatively well the PFE optimized by Tikhonov regularization in sand units of a gas reservoir. The obtained results indicate that PFE could provide initial information about sandstone reservoirs. It could estimate reservoir porosity distribution approximately and it highlights bright spots and fault structures such as gas chimneys and salt edges.

Plio-Pleistocene stratigraphic sequences and depositional model using 3D seismic interpretation constrained by well logs in Central Graben, North Sea

“…The North Sea Groups of Cenozoic era, approximately 1460 m in total thickness unconformably overlying the Chalk Group of Late Cretaceous. In North Sea region thermally subsiding basin (epicontinental basin received sediments from neighboring landmasses), were formed during Cenozoic era (Sclater and Christie 1980;Ziegler 1988;Jordt et al 1995;Sørensen et al 1997;Faleide et al 2002;Tetyukhina et al 2010;Benvenuti et al 2012;Mojeddifar et al 2015; Figure 1. Location map of F3-block: (a) subset of coordinate reference system ED50-UTM31, (b) Netherlands onshore and offshore boundaries and structural elements of the Late Jurassic-Early Cretaceous, modified after (Schroot and Schüttenhelm 2003;Kombrink et al 2012;Nelskamp et al 2012), (c) the seismic survey boundary of F3-block in blue, the location of the wells by black dots and the north-south and east-west cross sections by dashed lines.…”

“…The Middle North Sea Group (MNSG) about 350 m thick and the lithology of this group is mainly shale. The succession of Cenozoic era can also be separated into two packages by regionally marked Mid-Miocene unconformity (Deagan and Scull 1977;Kristoffersen and Bang 1982;Sørensen et al 1997;Overeem et al 2001;Winthaegen and Verweij 2003;Anell et al 2010;Tetyukhina et al 2010;Mojeddifar et al 2015). The lower package primarily contains Paleogene sediments (Lower and Middle North Sea Groups), which are comparatively fine grained (Steeghs et al 2000) than the upper package of Neogene sediments (Upper North Sea Group) about 700 m thick.…”

“…The lower package primarily contains Paleogene sediments (Lower and Middle North Sea Groups), which are comparatively fine grained (Steeghs et al 2000) than the upper package of Neogene sediments (Upper North Sea Group) about 700 m thick. Lithologically, Upper North Sea Group (UNSG) consists of coarser in grain size deltaic sandy-clay stone and sand, which exhibit complex geometries (Mojeddifar et al 2015). The Pliocene uplift of Scandinavia triggered the regression that caused the large influx of coarse sediments into the North Sea (Gregersen et al 1997;Eidvin and Rundberg 2001;.…”

Application of Spectral Decomposition and Seismic Attributes For Channel Geometry and Infill Lithology Determination: A Case Study from The Southern North Sea Basin

“…Several published works have discussed thoroughly various aspects of the post-stack time migrated 3D seismic dataset provided by dGB Earth Sciences in the F3 block. Some of these studies carried out in the study area are on delineation of geological features using spectral decomposition [18], independent spectral analysis [19], porosity prediction from seismic inversion [20] etc. Although these studies and others provide very rich literature on various aspects of the dataset, studies on prediction of the infill lithology of fluvio-deltaic channels particularly in the shallow (younger) sediments distinguishing channels filled with sand from those filled with shale are lacking.…”

The Application of Seismic Attributes and Wheeler Transformations for the Geomorphological Interpretation of Stratigraphic Surfaces: A Case Study of the F3 Block, Dutch Offshore Sector, North Sea

“…The role of the Wheeler Transformation when integrating it with seismic attributes has proven to be a powerful tool in seismic interpretation and identifying geological features. By combining these two methods instead of using it as a stand-alone tool, it has helped researchers to better understand numerous things as demonstrated in previous studies done in the Netherland Offshore F3 Block ( Figure 1) such as porosity prediction [13], fracture and fault characterization [14], structural interpretation [1,15], and turbidites characterization [16]. However, the application of Wheeler Transformation and using seismic attributes to identify geomorphological changes to reconstruct depositional history has been given little to no attention to date.…”