Dr. Heijn van Gent 

          now at Shell
          mail: h.vangent@ged.rwth-aachen.de (still active)
        

From 's-Hertogenbosch, the Netherlands.

Now at Shell (Advanced seismic interpretation R&D) , Rijswijk

2009-2011: PostDoc at Geologie-Endogene Dynamik, RWTH Aachen

2006-2009: PhD at Geologie-Endogene Dynamik, RWTH Aachen

2000-2006: MSc. at Faculty of Geosciences, Universiteit Utrecht, the Netherlands (master thesis partially at RWTH)

2009-2012 Fracture occurence from seismic and wells

When do what kind of deformation structures form, and how do (local) changes in stress influence the formation of these fractures, veins and deformation bands. In an Industry sponsored project we are trying to find out!

As part of this project, we visited SE Utah on a couple of ocasions, performing GPR in Canyonlands NP (poster) and counting deformation bands in Arches NP.

I work together here with Christoph, Zoltan and Michiel. Click on the figure for a gallery.

2009-2012 Stringer Geometries

Together with Frank Strozyk, I am working of quantifying the internal geometry of salt structures, based on 3D reflection seismic observations of the stringer. These geometries rival the internal part of orogens, both in complexity and size, but very little is known about the evolution of these structures, which play an important role in hydrocarbon-, geothermal- and evaporitic salt production and exploration.

The first results are published in JSG, bur a second paper on stringer geometries is submitted to a Geological Society of London - Special publication on salt (September 2011, preprint)

2007-2011 CT scans & Discrete Element Models of dilatant faulting

The analogue models of dilatant faults  I developed for my MSc Thesis (se below) are nice, but they have one major drawback, you cannot look INSIDE the models. Recently Marc Holland and myself have published on some first results of analogue models inside a CT-scanner, showing the 4D evolution of the open fracture networks in detail. The paper is available at EPSL (2011).

With Steffen Abe, we developed Discrete Element Models to model the analogue model, shown below. The results show that many of the structures in the analogue models are quite robust. We have recently published a contribution to JGR of our first results!

2008-2011 Tectonic controlled deposition of Upper Cretaceous Chalk

Previously, it was assumed that the upper Cretaceous Chalk of Danmark was deposited under relatively quite, pelagic conditions. Recently bottom currents have been inferred to be responsible for subtle structures in these deposits, but together with Stefan Back and Lars Reuning, we have found evidence of gravity driven transport, augmented by tectonic movement along basement faults, as well as the effect of saltstructures on chalk deposition.

A paper of this work is now published in the Journal of the Geological Society of London.

Active

"Fracture Occurrence and Density from Seismic and Well Data"

For this project I work together with Zoltan Komoroczi, on how to regonize small scale structures, surrounding faults in sandstone from seismic and well data.

• Project page

The effect of pre-existing fractures on fault evolution

Teaching

Since the beginning of my work at the Institute for Geologie – Endogene Dynamik in 2006, I have been actively involved with teaching of students, both on the BSc and MSc level, and also for foreign students. My teaching experience mostly focuses on computer-enhanced teaching. For example, I have been developing the course “Structural forward modeling” for MSc.-students, and lectured on “quantitative geology” a course that uses a spreadsheet-software to quantify geological processes. In addition I have been the logistical manager for several industry courses and courses held by external teachers. Every year I co-supervise a 2-day “Tectonics for beginners” field trip in the Belgium, and served as a “native guide” in the Netherlands for groups of Omani GUtech students on several occasions and have given several “town hall”-lectures on structural geology to mostly non-scientific audiences.

Stress and Strain from 3D seismic data

2006-2009. The evolution of stress fields gives insight in for example the plate tectonic development of an area, and at the same time, it Dynamic information will also further the understanding of smaller scale processes such as halo kinesis, fault reactivation and tectonic inversion.

The calculation of paleostress tensors (for example with Angeliers Direct Inversion Method, or Spangs Numerical Dynamic Analyses) is based on knowledge of both the orientation of fault planes, as well as the direction of slip on the faults. This slip vector is usually determined through direct field observations of fault kinematic indicators, such as slickenslides. This field based approach results in a relative under representation in paleostress studies of areas where the horizons of interest are not outcropping. This is particularly the case in sedimentary basins where direct fault observations are not possible.
We implement a 3-step workflow, based on the interpretation of 3D seismic volumes. We have access to the first class seismic data base of the Nederlandse Aardolie Maatschappij (NAM, Assen, the Netherlands).
The first step entails the detailed interpretation of horizons and faults on the member level. Special attention is given to detailed interpretation of kinematic indicators such as en-echelon fault assemblages, splays, fault bifurcations and other fault interactions. Also the fault cut offs of horizons will be studied in detail.
In the next step, these detailed interpretations are palinspastically reconstructed using 3D balancing software (3Dmove, Midland Valley). This step provides the movement direction of faults. Removing of younger deformation allows the restoration of older, deeper horizons.
As a third step, fault orientation and fault slip from different time periods are used to calculate the paleostress tensor. The Numerical Dynamic Analysis was the applied method, because the dataset was observed to be to complex for the Direct Inversion Method. Because the deformation of overlying horizons was removed from deeper horizons, a paleostress stratigraphy can be constructed.
Results show that paleostresses from the NW corner of the Dutch Groningen Gasfield correspond with known data from Germany, France and Great Britain. Principle stress directions are sometimes observed to switched, but this might be the result of the position of the study area on a structural high. The observed maximum horizontal compressive stress in this study corresponds with known data, such as the Neotectonic data from the World Stress Map.

Looking at smaller, non-reacted faults from the Upper Cretaceous Chalk Group, it was shown that the seismic roughness of these faults is independent of the interpretation direction, and thus not a result of the interpretation uncertainty. These undulations can then be used to confine movement directions, and thus to calculate the paleostress.

Zechstein Stringer

 

I published several peer reviewed papers on these topics (see below), but you can find my full dissertation here (as PDF).

The modeling of open fractures in gypsum powder

2005: Cosupervised by Janos Urai and Hans de Bresser (UU) See here for a description of my MSc thesis.

click here for all my publications