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within a volume known to represent porosity, for example, and the volume-grower tool will display all interconnected porosity within the volume (left). Because each voxel is defined in part by its coordinates, the distance between any two voxels can be measured. To facilitate this process, the Inside Reality system uses a ruler tool to provide a visual scale. This tool can be used to measure grain or pore size in three dimensions, helping geoscientists estimate pore-volume proportions and connectivity. Taking rock samples from the laboratory to an immersive visualization environment enables an asset team to share important information and concepts about reservoir samples so they can make more informed decisions. Inside Reality virtual reality technology lets geoscientists share 3D virtual core data with those in remote sites to help asset teams collaborate with company experts and partners around the world (below left).

&#62; Sandstone track ing. An opacity  lter has b een used to highlight q uartz grains in sandstone from a Rotliegendes gas reservoir in Germ any . In the volum e ( light gray ) , interconnected porosity ( b lue) is im aged using the volum e-grow er tool provided b y Inside Reality softw are. Fringe ( red) along the edge of the porosity indicates possib le connections to neighb oring pores detected autom atically b y the softw are. Carb onate cem ent ( orange) is also show n in the volum e. The horizontal slice show s q uartz grains ( dark gray ) , pore space ( b lack ) , carb onate cem ent ( m edium gray ) , and b arite cem ent ( w hite) .

Applications Rock fabric and textural data provide geologists with key information used in analyzing facies and in determining depositional environments. Geologists and petrophysicists can now obtain important information about grain size, shape and matrix from digital scans of core or core fragments. A single core-fragment image can yield thousands of individual grains. By digitally disaggregating grains in a scanned sample, analysts can obtain coordinates of all voxels composing each grain, the number of neighboring grains and grain-overlap information.1 5 From such a dataset, geologists can derive a comprehensive analysis of grain sizes and distribution to obtain a full suite of statistical

15 . Saadatfar M, Turner ML, Arns CH, Averdunk H, Senden TJ , Sheppard AP, Sok RM, Pinczew sk i WV,

K elly J and K nack stedt MA: “ Rock Fab ric and Tex ture from Digital Core Analy sis, ” Transactions of the SPWLA 4 6th Annual Logging Sy m posium , New Orleans, J une 26– 29 , 2005 , paper Z Z .

&#62; Visualization using Inside Reality technology . Bringing sam ple volum es into an iCenter secure netw ork ed collab orative environm ent allow s asset team s to b ecom e im m ersed in their data. Stereo proj ection creates a perception of depth, providing a different perspective on the 3 D nature of the rock and its

m icrostructure. Inside Reality visualization softw are provides a detailed im age of a foram inifera fossil m easuring 1. 5 x 1. 0 m m ( inset) . This 3 D visualization allow s ex am ination of the fossil from m any different angles. The anim ated avatar m irrors the pointing m otions and actions of another view er w ho is interacting w ith these data from a rem ote site.

The ability to manipulate opacity values plays an important role in the seedpoint and volume- grower tools featured as part of the Inside Reality toolbox. Using the seedpoint tool, the viewer selects a point within a slice or volume. This

point has a certain X-ray attenuation value. Once a point is selected, the program can automat- ically pick all neighboring voxels of a similar value that are connected to that point. This feature can help a geoscientist pick a point

16. Both the Udden-Wentw orth and the K rum b ein scales are used to classify rock sam ples according to diam eter; the form er is a verb al classi cation w hile the latter is num erical. According to the Udden-Wentw orth scale, sedim entary particles larger than 64 m m in diam eter are classi ed as cob b les.

Sm aller particles are peb b les, granules, sand and silt. Those sm aller than 0. 003 9 m m

are designated as clay . Several other grain-size scales are in use, b ut the Udden-Wentw orth scale ( com m only called the Wentw orth scale) is the one that is m ost freq uently used in geology . The K rum b ein scale is a logarithm ic scale, w hich assigns a value designated as phito classify the size of the sedim ent. Phi is com puted b y the eq uation: ø = – log2 ( grain size in m m ) .

17 . Arns CH, Averdunk H, Bauget F, Sak ellariou A, Senden TJ , Sheppard AP, Sok RM, Pinczew sk i WV and

K nack stedt MA: “ Digital Core Lab oratory : Analy sis of Reservoir Core Fragm ents from 3 D Im ages, ” Transactions of the SPWLA 4 5 th Annual Logging Sy m posium , Noordw ij k , The Netherlands, J une 6– 9 , 2004 , paper EEE.

18. Bennaceur K , Gupta N, Monea M, Ram ak rishnan TS, Tanden T, Sak urai S and Whittak er S: “ CO2 Capture and Storage— A Solution Within, ” Oil eld Review 16, no. 3 ( Autum n 2004 ) : 4 4 – 61.

10 Oilfield Review

1.0 m m
