66th EAGE Conference and Exhibition - Workshops

What is Meta-Gridding, and what impact does it have on reservoir modeling? Current practice in reservoir modeling relies upon the integration and utilization of data at multiple scales.

The efficiency, accuracy and stability of reservoir flow simulations strongly depend on the proper grid selection.

We are dealing with the direct conditioning of fine-scale geostatistical models to dynamic data, the updating process being no more conducted on the fluid flow simulation model (obtained after an upscaling step).

The reconciliation between irregular stratigraphic grids and regular seismic grids can be done in two ways for two different objectives: 1) Seismic modelling for 4D feasibility, 4D modelling as an help for 4D interpretation or geophysical validation of the static geomodel. 2) Integration of seismic attributes into the geomodel.

The amount and density of seismic data given as input in the Shared Earth Model is increasing continuously. Not only the seismic volumes are getting bigger but the size of the problem is multiplied by the various numbers of seismic attributes necessary to perform a full multi-attributes interpretation.

Magnetotelluric data are commonly acquired, processed and interpreted for the geothermal and mining industries with, in some cases, positive outcomes from data analyses giving useful and meaningful results. The impact on their respective businesses can be significant as well as being cost effective.

A SeaBed Logging (SBL) survey has been carried out by ElectroMagnetic GeoServices AS (EMGS) on a prospect in the Norwegian Sea. Good quality data were recorded with a total of 31 receivers along two crossing receiver lines. Processed data shows large and systematic MVO (Magnitude Versus Offset) responses in a limited part of the survey area. These MVO anomalies are most likely caused by subsurface resistivity variations. However, care must be taken when relating MVO responses to subsurface hydrocarbons. Pitfalls are present and a full integration with geophysical data is required in order to fully explain the observed anomalies.

The real potential of electromagnetic methods for geophysical applications is often underestimated. In other circumstances, the benefits offered by these methods are over evaluated.

Active source electromagnetic (EM) sounding bridges the gap between 3D seismic and exploration drilling by providing a method of mapping sub-surface electrical resistivity variations from the seafloor. While 3D seismic identifies the geological structures that may contain hydrocarbons, under many circumstances they do not reveal the presence of hydrocarbons themselves. Active source EM sounding exploits the large resistivity contrast between resistive hydrocarbon saturated reservoirs, and the surrounding more conductive sedimentary layers saturated with aqueous saline fluids. Under the right circumstances it can confirm the presence of hydrocarbons by identifying their resistive characteristics. This means that the possibility of drilling dry exploration wells is significantly reduced, as is the need for extensive appraisal drilling.