Essential elements and processes of the oil and gas systems in the Netherlands
Databases, maps and integrated basin modelling
TNO
|Knowledge for business
Advisory Group for the Ministry of Economic Affairs
Poster Verweij 07rk 01
TNO Built Environment and Geosciences Geological Survey of the Netherlands PO box 80015
3508 TA Utrecht The Netherlands
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Gas Composition
CH4 Crest CO2 N2 H2S StructElem Gas field Oil field
Gas composition of the Upper Rotliegend Group (RO) (version 18-05-2006)
Regional seal: Cretaceous Chalk and shales hold fluid overpressures > 10 MPa
Topseal breach allows hydraulic communication between L.Triassic and Jurassic units ->
equilibration of pressures 0
1000
20 40
Southernm part Central Graben Fluid pressure (Mpa)
Lithostatic gradient
Density corrected hydrostatic gradient Hydrostatic gradient
60 80 100 120 140 160
North Sea Group Chalk Group
Scruffand Schieland Group Lower Germanic Trias Group 0
2000
3000
Depth (mVDss)
4000
5000
6000
Temperature in wells at 2500m depth calculated with Temperature gradients from all data
Legend Temperature ranges
24.5 - 50.0 50.1 - 75.0 75.1 - 80.0 80.1 - 85.0 85.1 - 90.0 90.1 - 95.0 95.1 - 100.0 100.1 - 105.0 105.1 - 110.0 110.1 - 115.0 115.1 - 120.0 120.1 - 140.0 SALT Polygon from Gas
Figure 1 Location map showing structural elements in onshore and offshore Netherlands
Figure 4 Geochemical composition of natural gas in the Upper Rotliegend Group.
Figure 6 W-E cross-section through the southern part of the Dutch Central Graben and the Terschelling Basin showing the distribution of pore fluid overpressures.
Figure 7a) 3D geological model of the Terschelling Basin and southern part of the Dutch Central Graben
Figure 7b) Simulated present-day temperature: results from 3D basin modelling of the Terschelling Basin and the southern part of the Dutch Central Graben (using PetroMod Version 10.0 of IES).
Note the influence of salt diapirs on the temperature distribution
Figure 8 Simulated maturity history (1D extraction of 3D simulation run)
a
b
Figure 9 Top view of simulated present-day maturity at the Top Carboniferous in the Terschelling Basin and the southern part of the Dutch Central Graben (results from 3D basin modelling) Figure 2 Calculated
temperatures at 2500 m depth derived from geothermal gradients.
These geothermal gradients were calculated at more than 600 well locations using Bayesian least squares on approximately 7000 temperature measurements of different origin and quality
Figure 3 Maturity at Top Carboniferous. The maturity map is based on in-house measured vitrinite reflectance values of the Carboniferous at 115 well locations
Figure 5 Multiwell plot of pore fluid overpressure versus depth in the southern part of the Dutch Central Graben. All stratigraphic units from the Lower North Sea Group and older are overpressured. Very large variations in overpressure occur in the Triassic units
For information on Exploration and Production issues and E&P data see the Netherlands Oil and Gas Portal www.nlog.nl Introduction
TNO applies two approaches to increase the knowledge on essential elements and processes of the petroleum systems in the Netherlands:
1. Regional mapping;
2. Detailed mapping and 3D basin modelling.
Regional mapping
The TNO thematic mapping programme of the deep subsurface of Netherlands onshore and offshore aims to compile, analyse and map temperatures and rock and fluid properties (fluid = oil, gas, water) derived from released data from oil and gas wells.
In 2007 focus was on analysing and mapping:
- Temperature and geothermal gradients (Figure 2) - Maturity of Carboniferous source rocks (Figure 3) - Geochemical composition of natural gas
accumulations (Figure 4).
Detailed mapping and 3D modelling
As part of the TNO detailed mapping programme of sub- areas, special attention is paid to analysing and interpreting rock and fluid parameters. We use 3D basin modelling for the integrated interpretation of the wealth of data obtained in the detailed mapping project with the aim to increase the understanding and knowledge of the petroleum systems. The deliverables for the Terschelling Basin and the southern part of the Dutch Central Graben include:- Visualisation and analysis of rock and fluid parameters - 3D burial histories
- Petroleum system analysis.
Figures 5 and 6 present examples of the pressure versus depth plots and cross-sections used to characterise the fluid pressure conditions in the area.
Figures 7, 8 and 9 show selected results of the 3D basin modelling.
