New Methods of Volume Rendering with Examples from the Barnett Shale
James, Huw 1; Kostrova, Tatyana 2; Ragoza,
Evgeny 2
(1)Product Management, Paradigm, Houston, TX. (2) R&D,
Paradigm, Houston, TX.
The latest 3D graphics processing cards may have up to 6GB of
graphics memory and over 400 processing cores in their Graphics Processing Unit
[GPU]. This memory capacity allows useful volumes of 3D seismic surveys to be
completely downloaded to the graphics card as amplitude data instead of
serially in slices as 3D graphics data. The compute power of more than 400
cores is sufficient to perform volume rendering with variable opacity at near
real time. This change to sending seismic data rather than graphics data to the
card enables many other operations to be performed on the card rather than by
the host machine’s CPUs. This avoids delays waiting for new graphics data to be
sent from main CPU memory to the card. Operations such as band pass filtering,
complex trace attributes or proportional flattening can be performed instantly
now instead of by batch jobs. Once seismic data is on the graphics card, it can
be re-rendered over different ranges, using different opacity settings and
different color settings locally so rendering can be accomplished very quickly.
The compute power of the GPU need not be limited to just improving the speed of
rendering, it can also be applied to improving the quality of the rendered
image so that more information can be extracted by the interpreter. We
illustrate this by using data from a 3D seismic survey for the Barnett Shale in
the Fort Worth basin of Texas.
The Barnett shale is a marine deposit that lies on Ordovician limestones of the Viola/Simpson formations and dolomites of the Ellenburger group. The Barnett shale is overlain by carbonates and shales of the Pennsylvanian Marble Falls group. Porosity is low, less than 6% and permeability is typically less than one microdarcy. Production is accomplished though horizontal wells with artificial fracturing. The fracturing process may re-open large sealed faults reducing the efficiency of the process. Faults may penetrate either the water rich Ellenburger dolomite below or the Marble Falls limestone above and allow water to be drawn into the well jeopardizing production. The Ellenburger contains numerous paleokarsts which have caused the Barnett to sag into the collapsed cavities. These weak zones could also cause easy communication between the Ellenburger dolomite and bore holes in the Barnett. So an understanding of the historic faults, fractures and paleokarsts is important to well placement.
AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.