Case Studies

Precise Density Mapping

High accuracy and resolution of DMT enables us to make structural and tectonic maps, interpretation and models with higher resolution compared to conventional non-seismic geophysical data. Example demonstrates that DMT provides different information about studied area. Structural features interpreted with DMT were verified on seismic and borehole data.



*Detection of geological structures by DMT (left) and Sandwell gravity model (right). Spectacular identification of several structures is evident.

Structural and Tectonic mapping

Structural and tectonic mapping directly results from precise density mapping since complex structures such as faults, folds and juxtaposition of different structural blocks often create high density contrasts. Distribution of these contrasts, represented by high gradients on DMT data, allows to interpret structures, potential trapping system, role of faults in hydrocarbon migration paths, etc.

*Structural and tectonic mapping by DMT. Positive and negative zones in DMT data mark structural highs and basin areas. Steep gradients define position of faults.

Basement Surface and Structure

Higher densities of basement rocks compared to sedimentary sequences of basins make strong response in DMT data. DMT is therefore effective tool for exploration of basement surface and structure. Example shows basement surface (in seismic line) clearly reflected by 3D map of DMT data. The DMT enables us to determine structure of basement and outline structures with potential hydrocarbon occurrences in elevated fractured basement or in 4-way closures above basement arches.

*Identification of basement structure by DMT data. Seismic interpretation of basement surface compared with 3D map of DMT data clearly demonstrates high effectivity of DMT in mapping of basement surface.

Advanced interpretation of existing seismic data based on DMT

In many areas, seismic exploration reached its limits. One of the example, where additional methods are needed, is the sub-basalt exploration. Using the connection between the DMT technology and seismic data, numerous promising structures might be found below basalt layers.

*Accurate detection of elevated basement below basalts by DMT technology.

Tracking of geological structures out of the 2D seismic data

Resolution of DMT technology has potential to identify promising structures in sedimentary infill. Using limited number of existing data provided by our customer, Geo-Applications can track those promising structures to provide more accurate focus in the next exploration stage.

*Tracking of geological structures out of the 2D seismic lines

DMT Trend Surface

Trend Surface is commonly used tool in Petrel software. Its main usage is in numerous geological situations, when horizon correlates with base conformable horizon, but its reflex is not clearly visible in the whole area of interpretation. A similar approach was used by Geo-Applications to correlate DMT and basement surface. High level of correlation between the DMT surface and basement is an absolutely necessary prerequisite.

Example from UK Continental Shelf illustrates the difference in data value, if only one 2D seismic line is used (pic. a and b) and if the same line is used together with DMT Trend Surface (pic. c). Credibility of the results is presented in pic. d, where interpreted horizons on other 2D seismic lines are displayed together with DMT surface.

*Example of DMT Trend Surface from North Rona basin (UK Continental Shelf). Picture (a) shows one seismic line used for interpolation of basement surface (b) from this seismic line. Significant improvement of interpolation is achieved when DMT Trend Surface is used (c). Credibility of DMT Trend Surface was proved by additional seismic sections (d)