For the simple structural traps, the usual practice is to shoot a few 2D seismic lines to delineate the body in space. As these data make use of Two Way Travel Time (TWTT), unless highly refined velocity analysis is available, conversion of time sections into depth sections is a challenging task. However, making use of the well-log information, if the calibration for the producing litho-units is done properly, one can get very reliable information about the hydrocarbon distribution. Vertical Seismic Profiling (VSP) is useful for accurate delineation as it makes use of one-way-travel time. For complex areas, that means, areas having strong tectonic controls like thrust belts, 3D data acquisition is a must. For proper reservoir monitoring when at regular time intervals multi-component seismic studies are carried out, we have 3C4D. These data sets can only help to get very accurate hydrocarbon distribution in space and time.

Fluid contacts can be static / initial or dynamic after production. They are often inferred from observations at wells, seismic and  material balance at field / compartment scale. Well data consist in pressure logs, saturation logs, and fluid data - PVT consideration around fluid data can provide information about contacts beyond the depth range of well / reservoir intersection. Well data is usually sparse in time and space. Seismic is a critical source of contact information, through Direct Hydrocarbon Indicators (e.g. flat spot) but also because it can provide structural information. Establishing a good understanding of the petro elastic response of the rock is recommanded for DHI interpretation. It is very much used these days. Material balance is the most interpretative method but can help.

Formation evaluation can be gained from Petrophysical analysis of well logs in a field such as depositional environment, structural characterization, in-situ rock attributes and TOC carbon/oxygen ratios from pulsed neutron sources. To determine oil chemistries as a tracer tool to genesis, a spatial geochemical analysis should be performed as a first step in determining distribution patterns. Data should be plotted on a GIS base map that will allow future datasets added as overlays for correlation patterns. Remote sensing may be another such dataset.