Simulation of Coupled Evolution of Pore Pressure, Fluid Flow, Compaction and Temperature; Consequences for Correct Temperature and Maturity Prediction in Unexplored Areas and Unconventional Basin Settings

Hanneke Verweij¹, Petra David¹, Monica Souto Carneiro Echternach², Andre Bender³, and Jan Diederik van Wees^1
1TNO Geological survey of The Netherlands, PO Box 80015, 3508 TA Utrecht, The Netherlands
²Utrecht University, Faculty of Geosciences, Budapestlaan 4, 3584 CD Utrecht, The Netherlands
³Petrobras, Av. Jequitibá 950, Cidade Universitária-Q7, Rio de Janeiro, Brasil

From the very start, temperature and maturity prediction has been a major objective in the development and application of basin modeling tools for finding more oil and gas. In recent years, the increasing need for alternative energy supplies and durable resources has promoted a rapidly increasing interest in opportunities that the subsurface offers for providing geothermal energy and long-term geological storage sites of CO₂. Knowledge on the present-day temperature distribution is a prerequisite for a reliable evaluation of the use of the subsurface for these purposes. In addition to the application of basin modeling for petroleum related research, TNO incorporates basin modeling in research on these alternative purposes, for example in its workflow to predict the present-day temperature field and to construct temperature maps.

Basin modeling programs simulate the temperature evolution using heat flow equations that are based, amongst other things, on lithology- and porosity-dependent thermal conductivities. As a consequence, the temperature evolution and the calculated present-day temperatures and source rock maturation will be affected by the porosity evolution, and thus by the compaction models, porosity-permeability relations, and hydraulic boundary conditions applied. Because fluid flow is 3-dimensional, the related porosity and permeability evolution and the temperature evolution might be different for 1D, 2D and 3D simulations. In addition, ignoring the influence of fluid flow and pressure evolution on the development of porosity and permeability may lead to serious errors in predicted temperature and source rock maturation.

As part of the process of developing an appropriate generic workflow for incorporating basin modeling in the construction of temperature and maturation maps, we have evaluated in detail the effect of using different default and user-defined compaction and porosity-permeability relations for hydrostatic and hydrodynamic conditions in predicting porosity, permeability, pore pressure, temperature and maturity by running simulations with one commercial (Petromod) and two in-house developed basin modeling programs (SimBR of Petrobras and TNO’s Petroprob). We used synthetic test cases and a real case from an area in the salt-dominated and highly overpressured Netherlands offshore. This paper presents the results of this evaluation. We will show that ignoring, and also unjust accounting for, the influence of fluid flow and pressure evolution on the development of porosity and permeability may lead to serious errors in the predicted temperature and source rock maturation. This effect is especially important in overpressured but normally compacted deep basin centers, in salt-dominated basins and in rapidly subsiding basins with significant compaction disequilibrium. We would like to discuss these effects and their consequences for a successful application of basin modeling for temperature and maturity prediction at different depths in different basin settings.

 

AAPG Search and Discover Article #90066©2007 AAPG Hedberg Conference, The Hague, The Netherlands