Auditable volumetrics for fast and effective evaluation of hydrocarbon resources Within the newest release 2018.2, GeoTeric is enhancing the exploration workflow by introducing a ‘Volumetrics’ tool which allows calculation of oil and gas resource estimates at any point during horizon interpretation ...
Within GeoTerics’ Validate module it is possible to define rock properties from well logs to generate geologically accurate models. Once accurate rock properties are defined in a model, it is important to accurately replicate the geological scenario for which the model is testing. In some cases, using defined rock properties is not enough detail to replicate the geological depositional environment. To increase the accuracy of the model design it is possible to transition rock properties from one type to another.
Dip and Azimuth volumes are used in several ways in GeoTeric, from processes such as Noise Cancellation (SO FMH & SO Noise filters) to attribute generation (SO Semblance, SO Dip Derivative, SO Discontinuity, Flexure, etc...). The majority of these filters/attributes have the symbol SO in front of them, indicating they are Structurally Oriented.
The GeoTeric 2017.2 release not only included the release of the Adaptive Faults as part of our Adaptive Interpretation System, but also the ability to load and visualise data in floating point. The ability to load geophysical volumes such as Vp/Vs and Acoustic Impedance volumes with their original values allows interpreters to extend their subsurface analysis capabilities in GeoTeric.
GeoTeric’s Adaptive Fault Interpretation provides a fast and accurate interpretation system which improves the efficiency of your fault interpretation.
The Adaptive Faults are data following fault sticks, which snap to discontinuities in reflectivity data, attributes or CMY Blends. With just 2 clicks of the mouse you can have an accurate fault stick. The Graph Theory looks at how similar the attribute, or break in the seismic data is from the background and determines the best route from first click to where the cursor is located.
To start interpreting the faults, click on the Interpret module (figure 1) or right click in the 3D scene and select Adaptive Faults. Either option will bring up the main Interpretation menu in the 3D scene.
In the previous Geobodies instalment, a geobody was created using a Standard Frequency Decomposition (FD) blend as this technique is useful in identifying subtle changes within a geological feature. In this post, an Adaptive Geobody will be created using a High Definition Frequency Decomposition (HDFD) blend. The matching pursuit techniques used in GeoTeric’s HDFD blending generates frequency decomposition results as close to seismic resolution as possible. This improvement in vertical/temporal resolution is traded off in terms of accuracy of frequency resolution.
The Adaptive Geobodies tool tool is based on generating delineating geological deposits from data values using model based delineation. It is a powerful and flexible tool which can be used in multiple ways. The basic techniques will be shown below and in this instalment the benefits of using a Standard Frequency Decomposition blends for creating geobodies.
The benefits of the different Blending techniques were outlines in the previous blog posts and here we will look at using the Standard blending method to extract geological features. The Constant Bandwidth and Uniform/Exponential Constant Q are useful reconnaissance blends as they have very good frequency resolution but poorer temporal resolution. As a result it is possible to identify subtle frequency differences within these blends and subsequently extract them with the Adaptive Geobodies workflow.
RGB Frequency Decomposition Blends are extremely useful in identifying both structural and stratigraphic events. These are best observed in the Z domain as the effects of vertical smearing are minimized. When observed along the inline or crossline it can be harder to trace the stratigraphic events.
Bedform Indicator is designed to skeletonize the seismic response to highlight the relationship between seismic strata within the data set. It highlights bedform features such as onlaps and clinoforms. So, by combining the Bedform Indicator volume with the RGB volume it will be possible to map and track sratigraphic features in 3D.
Not all geobodies are discrete geological features that can be extracted such as channels or debris flows, sometime more large scale geobodies need to be calculated. This is often the case when analysing large reservoirs where a “tank of sand” model may be applied or if two horizons pinch-out making geobody volumetric estimations difficult. This is an important process as the Gross Rock Volume (GRV) is an essential input to the STOIIP or GIIP calculations. We can increase the accuracy of our GRV estimation with the use of existing horizons and the Adaptive Geobody tool.