18
22 Oilfield Review What does it take to decide to drill a well? If not knowledge that oil or gas lies in the target zone, it takes at least a strong con- viction, a confidence based on the best pre- dictions that current technology can produce. Not so long ago, that usually meant basing drilling decisions on analysis of aerial pho- tographs, gravity and magnetic surveys, geo- logic well log evaluation, occasionally on geochemical analysis of the terrain and finally on interpretation of 2D and 3D seis- mic surveys—all conducted independently. The workflow that led to an eventual deci- sion to drill was long and tedious, and fraught with human, mechanical and technical error. Massive reports, studies and surveys—reams of paper—from which the probable presence of hydrocarbons was to be determined, piled up on the explorationist’s desk. In less than two decades, however, com- puter technology has changed all that and culminated in today’s far better predictions that result from an almost uninterrupted work- flow integrating every discipline involved— geology, geophysics and petrophysics. To facilitate this level of integration and provide a higher degree of confidence, GeoQuest launched the GeoFrame integrated reservoir characterization system in 1993. With POSC-compliant architecture that is open to customer-developed applications, this system began with a comprehensive suite of petrophysical and reservoir analysis applications (see “Optimizing Elf Norge Workflow,” page 25). 1, 2 In 1996, it grew to encompass a complete suite of geological interpretation tools and comprise the first complement of a fully integrated database and interactive environment for petroleum exploration and production (E&P). In 1997, two state-of-the-art suites of geo- physical applications were added, the IESX and Charisma systems, to fill out the subsur- face segment of what will soon become a comprehensive information and earth-model- ing toolbox and, in the near future, an explo- ration-through-production project database. Streamlining Interpretation Workflow For help in preparation of this article, thanks to Michael Adams, GeoQuest, Gatwick, England; Lars Gåseby, GeoQuest, Stavanger, Norway; and Sheila Calkins, Hovey Cox, Susan Ganz, Bobbie Ireland and Kathleen Keeler, GeoQuest, Houston, Texas, USA. ARI (Azimuthal Resistivity Imager), ASAP (Automatic Seismic Area Picker), BorView, Charisma, CPS-3, ELANPlus (Elemental Log Analysis), Finder, FMI (Fullbore Formation MicroImager), Framework 3D, GeoFrame, GeoViz, IESX, InDepth, PetroView Plus, PowerPlan, PrePlus, ResSum, RockClass, SeisDB, SEISMOS, StratLog, StrucView, SurfViz, UBI (Ultrasonic Borehole Imager), WellComposite, WellEdit and WellPix are marks of Schlumberger. Epicentre and POSC are marks of the Petrotechnical Open Software Corporation. Fast GeoTie is a mark of Petrosystems. Recall is a mark of Z&S Geoscience Ltd. 1. POSC, the Petrotechnical Open Software Corporation, is a not-for-profit corporation dedicated to facilitating integrated business processes and computing technology for the E&P segment of the international petroleum industry. To that end, it has developed and delivered a software integration platform for E&P technical applications that is formed by a set of standard interfaces between petrotechnical software applications, database management systems, work- stations and users. 2.Balough S, Betts P, Breig J, Erlich A, Green J, Haines P, Landgren K, Marsden R, Pohlman J, Shields W, Smith D and Winczewski L: "Managing Oilfield Data Management," Oilfield Review 6, no. 3 (July 1994): 44-45. Martyn B. Beardsell Paul Vernay Elf Norge Stavanger, Norway Heather Buscher Larry Denver Rutger Gras Keith Tushingham Houston, Texas, USA A fully integrated and interactive, subsurface exploration and production software system can cut cycle time, produce more accurate drilling decisions and build teamwork.

Streamlining Interpretation Workflow

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Page 1: Streamlining Interpretation Workflow

22 Oilfield Review

What does it take to decide to drill a well? If not knowledge that oil or gas lies in thetarget zone, it takes at least a strong con-viction, a confidence based on the best pre-dictions that current technology can produce.Not so long ago, that usually meant basingdrilling decisions on analysis of aerial pho-tographs, gravity and magnetic surveys, geo-logic well log evaluation, occasionally ongeochemical analysis of the terrain andfinally on interpretation of 2D and 3D seis-mic surveys—all conducted independently.

The workflow that led to an eventual deci-sion to drill was long and tedious, and fraughtwith human, mechanical and technical error.Massive reports, studies and surveys—reamsof paper—from which the probable presenceof hydrocarbons was to be determined, piledup on the explorationist’s desk.

In less than two decades, however, com-puter technology has changed all that andculminated in today’s far better predictionsthat result from an almost uninterrupted work-flow integrating every discipline involved—geology, geophysics and petrophysics.

To facilitate this level of integration and provide a higher degree of confidence,GeoQuest launched the GeoFrame integratedreservoir characterization system in 1993.With POSC-compliant architecture that isopen to customer-developed applications,this system began with a comprehensive suite of petrophysical and reservoir analysis applications (see “Optimizing Elf NorgeWorkflow,” page 25).1, 2 In 1996, it grew toencompass a complete suite of geologicalinterpretation tools and comprise the firstcomplement of a fully integrated databaseand interactive environment for petroleumexploration and production (E&P).

In 1997, two state-of-the-art suites of geo-physical applications were added, the IESXand Charisma systems, to fill out the subsur-face segment of what will soon become acomprehensive information and earth-model-ing toolbox and, in the near future, an explo-ration-through-production project database.

Streamlining Interpretation Workflow

For help in preparation of this article, thanks to Michael Adams, GeoQuest, Gatwick, England; LarsGåseby, GeoQuest, Stavanger, Norway; and SheilaCalkins, Hovey Cox, Susan Ganz, Bobbie Ireland and Kathleen Keeler, GeoQuest, Houston, Texas, USA.ARI (Azimuthal Resistivity Imager), ASAP (AutomaticSeismic Area Picker), BorView, Charisma, CPS-3,ELANPlus (Elemental Log Analysis), Finder, FMI (Fullbore Formation MicroImager), Framework 3D,GeoFrame, GeoViz, IESX, InDepth, PetroView Plus,PowerPlan, PrePlus, ResSum, RockClass, SeisDB, SEISMOS, StratLog, StrucView, SurfViz, UBI (UltrasonicBorehole Imager), WellComposite, WellEdit and WellPix are marks of Schlumberger. Epicentre and POSC are marks of the Petrotechnical Open SoftwareCorporation. Fast GeoTie is a mark of Petrosystems.Recall is a mark of Z&S Geoscience Ltd.1. POSC, the Petrotechnical Open Software Corporation,

is a not-for-profit corporation dedicated to facilitatingintegrated business processes and computing technology for the E&P segment of the internationalpetroleum industry. To that end, it has developed and delivered a software integration platform for E&Ptechnical applications that is formed by a set of standard interfaces between petrotechnical softwareapplications, database management systems, work-stations and users.

2. Balough S, Betts P, Breig J, Erlich A, Green J, Haines P, Landgren K, Marsden R, Pohlman J, Shields W, Smith D and Winczewski L: "ManagingOilfield Data Management," Oilfield Review 6, no. 3(July 1994): 44-45.

Martyn B. BeardsellPaul VernayElf NorgeStavanger, Norway

Heather BuscherLarry DenverRutger GrasKeith TushinghamHouston, Texas, USA

A fully integrated and interactive, subsurface exploration

and production software system can cut cycle time, produce

more accurate drilling decisions and build teamwork.

Page 2: Streamlining Interpretation Workflow

Spring 1998 23

Optimizing workflow can make a compet-itive difference at every stage of a project,but particularly during the subsurface inter-pretation phase. Workflow entails not onlythe relational processes employed by indi-viduals and asset teams to fulfill their respon-sibilities in a project, but the separate tasksthey perform, the decision points they mustreach, the supporting tools they utilize, andthe data with which they are working.Numerous factors influence each of these,including personal behavior and prefer-ences, and time constraints, but each factoreither accelerates or delays the workflow.

For years, engineers, geologists, petrophysi-cists and geophysicists worked separately onthe same project, doing the work of theirown disciplines. They were often unable todraw upon the work and interpretations ofothers during their own deliberations simplybecause they didn’t have the necessary tools.The workflow was not integrated. They couldconsult with each other by physically pass-ing hypotheses and preliminary interpreta-tions to one another and then discussingfeasibilities among themselves—a time-con-suming, often exasperating process thatcould go on for months without producing aconfident prediction.

In response to the belt-tightening of the late1980s and the need to cut costs whereverpossible while simultaneously increasingefficiency, the petroleum industry E&P sectorhas undergone major reorganizations duringthe last decade. One new development wasthe establishment of more integrated opera-tions based on multidisciplinary asset teams.Thus, to enhance workflow, save time andprevent duplication of efforts in the geology,geophysics and petrophysics domains, acommon database was needed. The obviousbenefit: each member of these asset teamscould work, not only with his or her owndata and their applications, but with the dataand applications being used simultaneouslyby the other team members, and do so inter-actively and in real time.

The GeoFrame 3.0 system meets the chal-lenge of providing multidisciplinary teamswith the tools they need to cut cycle timebetween disciplines and in doing so,increases the predictive power of interpreters.It does this by way of a common, shareddatabase and a large, interactive applicationenvironment that encompasses the full rangeof oil and gas E&P data, but remains user-friendly to permit access and use withoutdatabase skills (above).

Project Data ManagementThe database is at the very heart of this sys-tem and provides a platform for a fullpanoply of E&P applications as well as end-user custom-designed software. Althoughusually unseen by the interpreter, thedatabase is interactive and plays an essentialrole in optimizing interpretations and work-flow, yet requires no special training. Despiteits sophistication, the system contains a fullrange of data-management tools that allowone to access and work with the databaseeasily and with a human interface that islearned intuitively.

Shared by every domain, these tools enablethe user to load, access, manage and unloaddata easily. All industry-standard formats areaccepted, and numerous flexibility featurespermit such tasks as tape previews, batchloading, filtering and name aliasing. Thedatabase project managers, workflow man-agers and data managers help organize theworkflow and allow geoscientists to concen-trate on their core tasks. The various managermenus streamline project setup; cross-refer-ence data indices to avoid data duplication;ensure naming consistency with access to anunderlying data dictionary; provide tools togrant immediate access to the database; and

Geophysics

Data Management

Petrophysics

3D Visualization

Mapping

Engineering

Borehole Geology

Model Building

Geology

■■E&P interpretation. The GeoFrame database is a fully integrated, interactive platform for every stage of the E&P cycle from explorationto development and production. Applications that plug into the database include petrophysics, data management, geophysics,

3D visualization, mapping, engineering, geology, model building and borehole geology.

Page 3: Streamlining Interpretation Workflow

24 Oilfield Review

field comprehensive database queries.Display preferences can be set, but easy tog-gling between different indices, units andcoordinate systems ensures efficient use oftime. Workflow chains maintain a history ofthe process steps, including those for inter-pretation, which are all captured in the com-prehensive project backup, ensuring that nowork has to be repeated because of uncer-tainty about what a previous interpreter didor which steps were taken to arrive at a par-ticular interpretation.

Spreadsheets provide a convenient displayof data. If additional information is desiredon any of the displayed wells, in a wellspreadsheet, for example, the geoscientistcan click on one of several icons in a conve-nient menu interface to obtain further dataabout any of the items in the spreadsheet orcan query the database for more detailedinformation, such as deviation and check-shot surveys or formation dip and azimuthused for TVT (true vertical thickness) or TST(true stratigraphic thickness) indexing.Spreadsheets are available for logs, surfaces,grids, markers and zones, and by summariz-ing key information at a glance, are powerfultools for quality control.

Tools for efficient data editing are intuitive,efficient and comprehensive. Virtually elimi-nated is the time spent in tedious log andcore depth matching and splicing, which isnow done proficiently and with improvedaccuracy, as are data repair, data functioningand borehole environmental corrections.

The user-friendly POSC environment pro-vides an arena for human interface in theform of style guides, icons, and pop-up func-tion and help notations. Cross-disciplinegraphics libraries are shared, and intertaskcommunications are fully implemented;information and selection on basemaps,browsers and spreadsheets can be commu-nicated from one application to another bythe simple click of a mouse. Whatever thedomain and regardless of what one is doingon a project, everyone within the project hasaccess to the same applications and data. Allchanges to data are immediately reflected inall applications—this thanks to the imple-mentation of the POSC Epicentre datamodel.The DLIS (digital log information standard)and Geoshare standardization of input-out-put exchange formats ensure that interpretersanywhere can merge their data into otherprojects or proprietary software applicationswith minimal effort and no reformatting.

As a consequence of the database and theinteractive environment, geoscientists cannow reduce the time spent analyzing data byan order of magnitude and make better-informed, faster drilling decisions with agreater degree of confidence and accuracy.

Geology and Petrophysics WorkflowThe geoscientist, an asset team member oran individual with interpretation responsibil-ity, often begins the workflow process bymoving data from the Finder master datastore or its equivalent, which houses thecompany’s validated, approved data, to aGeoFrame project. Alternatively, the inter-preter can query the database to learn whatdata are available and use the data loaders tobring in the data needed for a specific pro-ject, which may consist of well information,deviation, check-shot surveys, well logs, for-mation tops, previous interpretations, seis-mic data and more.

After querying the database to learn whatdata were available on the project, the geol-ogist might find that there were several wellswith log data, core data, some formationtops, an old nonexclusive 2D seismic surveyof the project area and a newly shot 3D seis-mic survey (above).

The choice is made to begin work with thewell logs, but it could easily have begunwith any of the other data. The data are pre-pared for analysis and given a position onthe workstation to await interpretation.Since the first stage is geology and petro-physics, the geoscientist clicks on the appli-cation manager, which provides a menufeaturing large icons for each discipline-specific application available in the system,then clicks on the geology icon and is pre-sented with a catalog of geological softwareprograms (right). At the click of a mouse are

■■Simultaneous access. With an integrated system, geologist and petrophysicist membersof asset teams can perform interpretations simultaneously with the geophysicists.

■■Managing interpretation processes anddata. The application manager providesaccess to all the necessary data loading,preparation and interpretiation tools witha click on the appropriate icons. There isno waiting for data transfers and updates.

(continued on page 29)

Page 4: Streamlining Interpretation Workflow

Spring 1998 25

Elf Norge (Elf Petroleum Norge AS) needed to con-

solidate its project data and results into a single

reference database in order to streamline its inte-

grated studies workflow. The Stavanger-based

subsidiary of the French Elf Aquitaine Group was

already using the Charisma and StratLog applica-

tions, so the decision was made, according to

Martyn B. Beardsell, Elf Norge Senior Reservoir

Engineer, to test and evaluate the new GeoQuest

GeoFrame 3.0 system to determine if it could

be the single-source solution that would fit the

company’s strategy for integrated studies and

asset-oriented teams.

Elf Norge had several specific, key objectives.

It was looking for improvement over previous

programs in areas such as interpretation, struc-

tural and geological modeling, incorporating new

data as soon as they were brought into the

database, in order to monitor the operator’s activi-

ties in the field. It wanted to be able to house both

data and results from a specific project in a sin-

gle, open project database, regardless of whether

or not the work was performed with GeoFrame

applications. It wanted to determine if these appli-

cations could complete its interpretation chain, in

effect to learn if work performed with the WellPix

and ResSum modules could replace that done

using another reservoir software system, and to

assess whether the CPS-3 application could

replace the mapping and model construction mod-

ules previously used.

Elf Norge sought to determine if this system

would improve workflow in an integrated soft-

ware and database environment, whether it

would increase interpretative output, whether it

would produce faster yet better quality results,

and whether it would be appropriate for complex

geology and drilling projects. And it wanted to

know if the system could provide a common pro-

ject database accessible by a wide variety of

applications employed by a multidisciplinary

project group.

The GeoFrame 3.0 system was installed at

Elf Norge in November 1997 and evaluated on one

of the North Sea’s largest and most complex pro-

ducing fields, the giant Oseberg field in Blocks

30/6 and 30/9, some 130 km [80 miles] northwest

of Bergen, Norway. Operated by Norsk Hydro in

cooperation with its partners Statoil (Den Norske

Stats Oljeslskap), Saga, Mobil, TOTAL and Elf

Norge, the field holds recoverable reserves of 325

million m3 [2 billion bbl] of oil and 115 billion m3

[4 trillion ft3] of gas (above).

Optimizing Elf Norge Workflow

■■Oseberg field. A complex of five major sectors, the Oseberg field lies in the mid-Norwegian North Sea.

Page 5: Streamlining Interpretation Workflow

26 Oilfield Review

Oseberg is a massive complex of dipping Brent

reservoirs with gas, oil and water.1 At its heart is

Oseberg Field Centre, composed of Oseberg A and

Oseberg B in the southern part of the field.

Oseberg C is situated 14 km [8.5 miles] north

of the Field Centre, while Oseberg East lies just

east of Field Centre, and Oseberg South 13 km

[8 miles] south of Field Centre. At Field Centre

there are some 24 oil-producing wells, two of

which are subsea, and ten gas and water-injection

wells. Oseberg C produces oil from 25 wells and

has eight gas and water-injection wells. Oil pro-

duction is expected to begin at Oseberg East this

year and from Oseberg South next year.2 Plateau

production of oil from the entire complex was in

excess of 500,000 B/D [79,450 m3/d]. Oil produc-

tion is anticipated to continue until the year 2017.

Gas sales are set to begin in 2000.

Elf Norge’s objectives in the Oseberg study

were to use the system to build a geological

model of the field, integrating all available data,

and to see if the system would allow new, more

efficient workflow capabilities in the process. An

evaluation team was established composed of

three geophysicists working with the Charisma

and GeoViz applications; four geologists working

with the WellPix, StratLog, SurfViz and

Framework 3D applications; and three reservoir

engineers working with StratLog, WellPix,

ResSum, SurfViz, Framework 3D and CPS-3

models; as well as management personnel. An

additional eight technicians used the data man-

ager and StratLog applications to prepare project

data and carry out various geological and geo-

physical tasks in conjunction with the interpreta-

tion process. The team was split between sever-

al projects including the Oseberg study.

Paul Vernay, the Elf Norge Head of Exploration

Support and Data Management, says earlier tests

of the system between February and May of 1997,

had shown that most of the functions needed to

monitor operator field activities were provided by

the system and its embedded applications. The

Oseberg study, he says, was essentially to confirm

those results and decide on the database and

application platform to be used on Elf Norge’s

nonoperated fields.

3D modelbuilding

VisualizationDepthconversion

Averaginglayers

Kriging

Binary

Gridding

Pickinghorizons

ASCII

DeviationASCII files

Link

Link

Well logs

Geoshare

Seismicinterpretation

■■Elf Norge integrated studies workflow.

Page 6: Streamlining Interpretation Workflow

Spring 1998 27

To produce its 3D geological model of the

Oseberg field, complete with faults, Elf Norge

loaded its test well logs from its Recall master log

database into the database, while the formation

tops and deviation surveys were loaded as ASCII

(American Standard Code for Information

Interchange) files, before both were transferred to

the GeoFrame project database.

Interpretation began with the geologist using

the WellPix and StratLog modules to pick major

horizons in depth so they could be fed to the geo-

physicist for use in creating synthetic seismo-

grams and in seismic interpretation. Once the

major horizons were completed, then both disci-

plines worked at the same time, with the geolo-

gist analyzing the layers with the ResSum mod-

ule. The major horizon picks were Top Brent, Base

Brent and Base Cretaceous. The Brent was subdi-

vided into 10 reservoir layers.

Gridding was accomplished with the CPS-3

application, and kriging was done with

Petrosystems’ Fast GeoTie module.3 Thereafter,

geological modeling of the faults was done with

the Framework 3D application, while visualization

was done with the SurfViz module. The seismic

interpretation performed earlier with the Charisma

application was upgraded to the GeoFrame 3.0

system and then converted to depth with the

InDepth program (previous page).For detailed correlation of the wells, the true

vertical thickness (TVT) of geological objects

such as channels was needed. The ResSum

module was used to calculate the TVT and aver-

aged petrophysics. The true vertical depth (TVD)

was first obtained, then the TVT was derived from

the dip and azimuth at the well locations. The

CPS-3 application was used to evaluate layer,

dip and strike grids from the seismic horizons

depth grids. The program then extracted the grid

value at well locations to produce dip surveys at

each well location.

The WellPix and StratLog modules rapidly

defined horizons, according to Beardsell, and, he

says, the horizons and fault segment data were

transferred efficiently from the Charisma interpre-

tation application to the CPS-3 application, as

were the surfaces from the CPS-3 module to

Petrosystems’ Fast GeoTie program. The binary

read-write was also quick. Altogether, he notes,

“It was an excellent combination of functionali-

ties. In particular, the fault and horizon model

construction was very impressive, and the CPS-3

application’s mapping and volumetrics functions

were very powerful.”

The GeoFrame system proved to be fast. With

it, a framework from picked seismic and geologi-

cal isochore maps was created in one day, which

included correctly picking faults on the seismic

data and time-to-depth conversion.4 It took only an

hour to add a fault or to modify existing faults,

and just 15 minutes to add a new horizon from an

isochore map or to check errors in wells versus

the model. And an Allan diagram, which shows

the lateral displacement variations along a fault,

was produced in only 5 minutes.

Elf Norge concluded that the new system offered

significant gains in efficiency and coherency

between the different disciplines. The tight links

with InDepth and CPS-3 applications make it

possible to save days of valuable time. The

availability of horizons, well data, trajectories and

layer averages for mapping avoids errors and is

fast. The Framework 3D-InDepth combination to

produce fault models in depth is a major advance,

and the incremental update of the Framework 3D

model dramatically improves update time and

accuracy in a development environment.

“Coherency is the key to understanding how our

definition of models of fault patterns, structural

models and geological models has improved,”

Vernay said. “The improvement has clearly to

do with the 3D functionalities of the GeoFrame

system, and in particular to its GeoViz,

Framework 3D and SurfViz applications. A better

integration of data through the GeoFrame struc-

ture means definitively for us a better integrity of

the data and an improved accuracy of the data.

The risk of error is minimized because all the pro-

ject members are accessing the same set of data

and are able to react immediately when they find

an error by cross-checking information from one

of the other domains with the data they are expert

in. And once the project database is built, the

tools to build and visualize 3D models, the SurfViz

and Framework 3D applications, are considered

very efficient and useful for evaluating a well pro-

posal from an operator.”

Elf Norge has now reached the end of the evalu-

ation phase. The recommendation to use the sys-

tem as the project database for interpretation pro-

jects on its nonoperated fields, to use the

Charisma and GeoViz applications for seismic

interpretation, and to perform all geology and

structural model construction with GeoFrame 3.0

applications is about to be issued.

1. George D: "4D: The Next Seismic Generation?" OffshoreMagazine 54, no. 10 (October 1994): 22.

2. Norsk Hydro web page: http://www.hydro.com/gas/eng/,"Operated Fields: Oseberg."

3. Kriging, named for Daniel G. Krige, is a spatial-domain sta-tistical method for determining the best linear unbiasedestimate of a value at an unknown point.

4. Isochores express variations in the thickness of rock units.

Page 7: Streamlining Interpretation Workflow

28 Oilfield Review

■■Correlating well logs. In this example,the interpreter first used the WellEdit module to depth match log curves to eachother and interactively shifted the coreporosity data to match the porosity log.The corrected data output from theWellEdit module increases the accuracy of log analysis and geologic correlation later in the workflow process. The edit history appears in the lower right corner.

■■Visualization of project well logs. TheWellComposite module allows team members to see and work with well logsand other key well information, such asborehole equipment diagrams.

Page 8: Streamlining Interpretation Workflow

Spring 1998 29

all the modules and tools needed for geo-logical and petrophysical interpretation:WellEdit, WellComposite, PetroView Plus,StratLog and WellPix programs.

Well logs provide a record of rock andfluid properties with depth in a well. Withthe WellEdit module, a data-preparationprogram, the geoscientist is able to carry outa comprehensive quality check (QC) of thewell data. Logging is done at different times,and the curves are not necessarily on depthwith each other, so this module allows thegeoscientist to look at the well data and edit the log curves to depth match them(previous page, top). The user can splice, filter,patch, and apply user-specified formulas todata and edit values in spreadsheets. Themodule also provides several precise depthmatching and resampling options to bringcurves into near perfect alignment, whichgreatly enhances the quality of marker pick-ing, curve correlation, petrophysical analysisand synthetic generation.

Easy to use, with click-and-drag or typed-inchanges, the module also helps save timewith its new, simple script language forbatching and scripting of repetitive tasks, itspowerful undo functions, and the possibilityof propagating changes such as depth shifts toother curves in the database. Original data,however, are never overwritten. New curvescreated in the WellEdit module are savedwith a complete edit history or audit trail, sothat it is always possible to know who didwhat to the data and when.

The geologist or petrophysicist works withthese data in a shared graphics display tem-plate created in the WellComposite module(previous page, bottom). To expand theinformation available in the display, datacould be added at this point, for example, toshow permeability, porosity, pore-size distri-bution, fluid content and mineralogy.Photographs, computed logs, descriptivetext, synthetic seismograms, well tops andborehole equipment can also be added. Asa consequence, a wysiwyg (what you see iswhat you get) well composite is produced atany scale, in any index.

Lithologies can be classified using theRockClass module, which generates a strati-graphic column based on a statistical clas-sification of wireline logs, computedmineral volumes or core data (right). It per-mits interactive definition of clusters ofpoints on crossplots—as many as nine clus-ters can be used simultaneously—to buildup a lithological database.

■■Classifying lithologies. The RockClass module allows users to define a lithologicaldatabase using crossplots (bottom) and automatically generate a lithologic column (top, middle track).

Page 9: Streamlining Interpretation Workflow

30 Oilfield Review

Moving into the petrophysical domain, thegeoscientist may want to correct the logs forborehole environmental effects. Factors suchas temperature, salinity and even boreholesize can adversely affect certain logs and canbe compensated for. The PrePlus moduleautomatically detects the logging vendor andtool type and sets up the correction stepsaccordingly. Quality-control displays showdata before and after correction.

The geoscientist’s log analysis is accom-plished quickly and accurately with thePetroView Plus module, one of theGeoFrame system’s powerful log analysispackages (right). Capable of input from bothstandard- and high-technology wirelinetools, it encompasses shaly sand, carbonateand Archie formation models, and computesshale volume from combinations of shaleindicators. And it can handle porosity fromsingle logs, crossplots, or user-defined func-tions. Both industry-standard saturationequations and an option for user-definedwater saturation equations are available.

Simple enough for generalists and occa-sional users, yet detailed enough for forma-tion evaluation specialists, the PetroView

Plus module takes a step-by-step approachin guiding the interpreter through a com-plete, deterministic, petrophysical evalua-tion. From the main menu, the interpretersimply moves from subtask to subtask, top to bottom, left to right. The module pro-vides interactive parameter selection fromcrossplots, histograms and log displays. Ateach stage, a graphical display appears to allow the quality of the preceding work to be checked.

Occasionally, petrophysicists need a morespecialized log analysis technique.ELANPlus software is the advanced petro-physical analysis package that computes themost probable solution of mineral and fluidvolumes using a multilog least-squares inver-sion technique. It is especially valuable foruse with complex lithologies and with vary-ing fluid and porosity types. The analystbegins by first proposing a formation modelconsisting of mineral, rock and fluid typesthat are to be solved for, based on what isknown about the formation mineralogy. Thenext step is to select a set of log curves andset the values for the mineral, rock and fluidparameters as they relate to the logging tools.

Both petrophysical modules function inmultiwell modes, where efficient crossplotanalyses, including curve fitting, data func-tioning, log normalization and missing-curveestimation can be performed. By applyingthe session files with model and parameterinformation to other wells, individually or ina multiwell mode, the analysis is completedrapidly and with greater efficiency.

The system also has a reservoir summationmodule, if the interpretation requires it. Itcarries out accurate calculation of reservoirlayer thicknesses and averages zone proper-ties such as porosity, permeability and watersaturation from the log analysis results (left).Flexible and efficient, it allows a choice ofcurve inputs and zones. Cutoff values canvary by zone or by well. Easy to use, themodule automatically selects the mostrecent curve version, but permits rapidqueries to select alternative curve inputs, andpropagates cutoff values to other zones tospeed setup.

Before this system, dip and image data,when available, were often analyzed only bya specialist. In the new environment, how-ever, interpreters can use tools to revealdetailed structural and stratigraphic informa-tion and combine it with the petrophysicaland interwell geologic interpretation for thebest description of the reservoir. Utilizing thissuite of near-well geological analysis andinterpretation tools, processing borehole dipand image data is rapid, highly accurate andvirtually automatic. Data measurements arecorrected, equalized and interactively scaledto absolute resistivity where appropriate, andthe image can be normalized to obtain max-imum detail. Strike (the azimuthal directionof a plane such as a bedding or fault plane)and dip (the departure from horizontal of

■■A deterministic petrophysical analysis.In a step-by-step process using thePetroView Plus program, water saturationhas been computed from other log curves:gamma ray, input density (green curve),computed density (red curve), computedporosity—gas (red shading) and water(white shading), and volume analysis—shale (dashed gray shading) boundwater (checked gray shading), sand (yellow) and gas (red shading). Flags indicate bad hole conditions.

■■Measuring layer thicknesses and averaging zones. The reservoir summation modulecarries out numerous processes to determine reservoir characteristics correctly. Thispanel shows layer names, depths of their tops and bottoms, thicknesses and porosities.

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each rock layer) of subsurface formations arecomputed, faults and unconformities arelocated, and manual structural and strati-graphic interpretations are facilitated and sta-tistically analyzed through the systeminterface (left). Another module displays geo-logical structures in the near well area usingdip results, which allows determination ofwhether the structure is a fold or a normal,growth or reverse fault. Dip results are storedin the common database and shared withother modules.

The borehole geology modules allow awide range of interpretative and analyticalprocedures, including images of dipmeterdata. Interpreted dips picked in one windoware integrated and interact with stereonets,histograms, rosettes and other plots to aid inthe interpretation (below left). Accurate sandpercentages from the high-resolution datacan be determined in thinly bedded reser-voirs by image histogram thresholding, andfractures can be identified and their orienta-tions determined to detect local stress direc-tions as an aid to planning fracturestimulation. Furthermore, since fractureporosity is the key to economic recovery inmany reservoirs, the borehole module canbe an important tool in computing fracturecoverage, and mean and hydraulic aperturefrom calibrated resistivity images.

Geological Interpretation Workflow With the data in view, the geoscientist beginsthe geological interpretation with two pow-erful tools that work simultaneously toimprove the precision and reduce the timetaken to pick geological markers, theWellPix and StratLog modules. Together,they greatly simplify data manipulation byemulating what was once laboriously doneon paper but is now accomplished with afew clicks of a mouse—well-log correla-tions, cross sections and basic mapping. Theworkstation screen becomes the draftingtable to select, move and display logs for cor-relation. Wells can be compared quickly andefficiently by moving them side by side andscrolling them to align with one another.Tops can be extracted from maps and gener-ated from user-guided and automatic corre-lation algorithms. The interpreter can moreeasily pick tops using logs that are color-

■■Dip and image interpretation. Interactive dip picking from image data, enabling theinterpreter to identify and interpret structural and stratigraphic features is acceleratedwith this new system. Here, no sedimentation features are visible, but the dark streaks crossing tracks 2 and 4 are structural mud-filled fractures. Track 1 shows caliper data;track 2 is FMI Fullbore Formation MicroImager data; track 3 represents automatic orhand-picked dip results; track 4 displays ARI Azimuthal Resistivity Imager data; andtrack 5 shows UBI Ultrasonic Borehole Imager data. The interpreted dips in track 3interact with stereonets, histograms, rosettes and other plots.

■■Comparing dip to seismic images. Like other project data, dip results are stored in the database. In this depth cross section, apparent dips are shown in green on the well.By comparing dip data to seismic data, the geologist can validate an interpretation.

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coded according to their curve value, andcan utilize ghost curves to stretch andsqueeze portions of curves to better interpretfaults or intervals that appear to thin orthicken (top). Markers can be highlightedand quickly correlated to geophysical sur-faces. All the logs in the display can beminiaturized simultaneously for a quick sec-tion display that expedites definition of thetops and units.

The WellPix program works hand in handwith the StratLog module. Once the markershave been picked, interpretation of the stratabetween the wells begins with automatic

marker-ties and the generation of anenhanced geologic cross-section hypothesis(above). Displays that encompass all avail-able data in the well can serve as a templateand automatically be used for other wells.These displays are added to the cross sec-tions so the geologist can begin the interwellinterpretation. The autotie functionality willquickly create correlations by tying forma-tion tops together from well to well.Correlations can then be edited, createdmanually, or even extracted into the crosssection from existing maps. Furthermore,

flattening on a particular correlation can givean indication of the geology at the time ofdeposition, and gaps in the well display atfault locations can help to reach a betterunderstanding of the fault displacement.

The StratLog cross section is enhanced withmultiwell time and depth functions, whichpermit display and interpretation of crosssections accurately in either depth or time,with or without seismic data, by incorporat-ing the check-shot information at each well.With seismic traces, however, the fully inte-grated module makes possible a detailedinterwell interpretation of structure andstratigraphy for any cross section by allowingthe extraction of seismic traces from anyexisting 3D volume in the database andinserting the traces into the cross section’sbackground (next page, bottom).

To check the quality of the correlations fromsection to section, the geologist may employthe 3D visualization techniques found in theGeoViz software, which provides a fully flex-ible, three-dimensional workspace that is ofequal value to both the geologist and geo-physicist for both 3D visualization and inter-pretation (next page, top).

Both GeoQuest seismic interpretation sys-tems, IESX and Charisma, are now a part ofthe GeoFrame environment and are fullyintegrated with all other modules. Therefore,regardless of which interpretation system isused, the geoscientist is able to movesmoothly from domain to domain and func-tion to function, thanks to the intertask com-munications capabilities and shared projectdatabase built into the system.

One of the benefits that the Charisma andIESX suites brought to the system was theaccessibility of seismic traces to the otherapplications being utilized. With them, forexample, the geologist could see that thestraight-line autoties that were made didn’treflect what was happening in the seismicdata. Therefore, near the end of the initialinterpretations, these first interpretationscould be corrected by working in bothdomains, interpreting between the wellswith the StratLog module, using the seismicdata and working in both time and depth.The interpreter can bring the seismic data todepth, provided there is good control on thetime-depth curve or if there is depth indi-cated on the seismic traces. This is accom-plished because of the integration and speedbuilt into the system, which leads to a moreprecise result.

■■Picking geological markers. Variable area color fill, quick sections, ghost curves andmultiple templates are among the many functionalities of the WellPix module that maketraditional paper correlations almost obsolete for analyzing well logs. A bright-spot sandmember is selected as the geologic marker and tied in on all four of these well logs.

■■Updating cross sections. The StratLog application facilitates rapid generation andupdates of cross sections using lithology fill, deviated wellbore and flexible compositedisplay as shown in this panel.

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Geophysics WorkflowThe value of integration and intertask com-munication becomes readily apparentwhen the geophysical data come into play.The single-project database promotes dataand interpretation integration for cross-dis-ciplinary workflow; thus, while the geolo-gist and petrophysicist members of the assetteam were working through their own pro-cesses of data-quality check, preparationand interpretation, their geophysicist coun-terpart was in all likelihood working in par-allel with them.

As in the geological and petrophysicalworkflow, the process of geophysical inter-pretation begins with data loading; this time,however, it is the seismic traces that areextracted from the Finder master database’sSeisDB seismic archival system or loadeddirectly from tape. Regardless of whether it isa 2D or 3D project, all the available data areplaced on the GeoFrame platform, and thegeophysicist examines the initial cube dis-

■■Inserting a seismic background. The integration of geological and geophysical interpretations is achieved by simply overlaying3D seismic traces on a geological interpretation.

■■3D visualization.The GeoViz application permitsoptimal three-dimensional visualization of thedata as they areinterpreted. Here,hydrocarbon-bearing sanddeposits (yellow)on the down-thrown side of agrowth fault arehighlighted. Theuppermost horizonis truncated by anunconformity.

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play to determine what format the seismicdata should have, 8 or 16 bit—if attributeanalysis is to be done, the highest possibleresolution is desirable. In addition, at thisstage the geophysicist decides which mod-ules are likely to be used in preparing andinterpreting the data and loads them from theFinder database as well (above left).

If the project is both 2D and 3D, differ-ences in seismic acquisition parameters orphase must be addressed for a consistentinterpretation. Ordinarily, this means adjust-ing the 2D data to the 3D, so the geophysi-cist runs any filtering or deconvolution thatneeds to be done and does the phase rota-tion and shifts to match the 2D with the 3D(above right).

■■The geophysical workstation. The geophysicist is able tobring into the interpretation all the work, interpretations andupdates that other asset team members have contributed tothe project.

■■Tying 2D and 3D data. Tying the differ-ent vintages of 2D data and ensuring thatthese match the 3D data are achievedwith a mistie analysis module. Phase dif-ferences, static shifts and horizon mistiesare compensated for with an analysis toolprior to interpretation. Here, the phase cor-relation (red) and the correlation coeffi-cient are established interactively.

■■Panning through the data. The geophysicist is able to pan through the seismic datausing volume cuts and transparency to search for significant features. Here, a volumecut along an interpreted horizon surface reveals an area with major bright spotanomalies (red).

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Once data preparation is complete and allthe necessary tools are at hand, the geophysi-cist returns to the GeoViz application andbegins the interpretation by scanning theentire cube of data, stepping through theseismic traces while exploring progressivepermutations, shifts and changes that are cre-ated by stratigraphic incidents and interrupt-ing faults in substrata. When a significantevent is seen, for example a bright spot, thegeophysicist centers on this and then pansfarther through time slices, exploring theextent of fault systems and the magnitude ofany anomalies (previous page, bottom).

Much information can be seen ahead ofthe central interpretation phase. It may bedetermined if the bright spot is a major fea-ture at the particular level of the seismicdata. Then, if it is not a frontier explorationand there is well control in the area, welllogs can be matched to the seismic data todetermine the potential for a hydrocarbon-bearing reservoir.

A synthetic seismogram can be producedat this point (above right). All the well logsare brought into the interpretation, and aseismic wavelet is extracted from the vol-ume. The wavelet is taken from an actualwell path allowing a truer representation ofthe earth response than by using a standardformula wavelet. This allows a more exactmatch of the synthetic with the seismicresponse and makes it possible to identify adeflection in the log as the base of the reser-voir and another deflection as the top of thereservoir. As a result, the geophysicist will beable to recognize, for example, the seismicresponse of a specific sandstone, and under-stand how lateral variations in reservoirproperties are encoded on the seismic data.

The interpretation begins with the trackingof a seismic event. Traditionally, this wasdone by tracking along whatever continuousor easy to correlate events the geophysicistcould see in the data, generally following thedirection of the acquisition by taking inlinesand crosslines at a fixed increment. With thesystem, it is possible to take full advantage ofhaving a 3D volume that can be manipu-lated in many ways and examined from anyperspective (right). In this case, rather thanfollow inlines to see where they lead, thegeophysicist can simply add a distinctivecolor to specific events, or flood-fill them, bypointing at reflections that appear interestingand clicking on them. Automatically, theGeoViz Voxel function flood-fills the entire

■■Synthetic seismogram. To achieve a precise estimate of the phase and spectrum ofthe data for an accurate synthetic seismogram, a wavelet (track 5) is extracted fromthe seismic volume. The third column shows synthetic trace computed by combiningthe extracted wavelet with the reflectivity (track 1). It compares well with the seismictrace along the wellbore (track 2).

■■Autotracking. Both IESX and Charisma applications have user-guided autotracking tools that allow quick and precise interpretation of specific seismic events. The left paneldisplays a horizontal cut called a time slice at constant time (upper left) and a vertical cutat an interpreted seismic section (lower left) through a cube of seismic data. The eventbeing tracked is shaded green. The right panel displays successive horizontal time slicesas the event is tracked down through the cube of data.

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structure, isolating it from the rest of thestrata and making it easily interpreted andsaved to the basemap for later reference(above left).

Once this segment of interpretation is saved,the focus may move across a fault. If problemsare encountered trying to reconcile dataacross a fault, for example, correlation toolspermit cutting out sections of seismic data andtransposing them onto another section—suchas on the other side of a fault—to correlate thenext leg of the event with its continuation.

Another technique that reduces the timecycle of going through and interpretinginlines one at a time is the use of automaticarea tracking. By knowing where the top ofthe reservoir is and what the seismicresponse is, tracking can be done automati-cally across the event with just two clicks,filling the full structure with easily differenti-ated color for rapid interpretation.

Traditionally, in a typical environment, thegeophysicist would have to move back andforth between the basemap and the seismicdisplay, selecting in turn individual lines thatintersected the horizon and watching to seewhere the interpretation fell. In this new sys-tem, however, three canvases can be usedand a multitude of tracking techniques areavailable to flood-fill away from the controllines automatically to identify most if not allof the reservoir, blocked only by faults. Itplaces the interpretation exactly where itneeds to go and reduces the time cycle byfacilitating movement through the datamuch more quickly and efficiently.

■■Voxel picking in the GeoViz application. With the GeoVizVoxel module, specific anomalies can be separated, visualized, illuminated and interpreted. In this case, the Voxel interpretation from a reservoir unit by a fault and the gas-water contact are displayed in red.

■■Correlation mapping. A correlation map is extracted from theseismic data to make lateral changes in the seismic traces moreapparent. The correlation is low where strong changes occur as aresult of facies boundaries or faults (dark colors). High correlation,implying a constant seismic character, is shown in yellow. Theexample shows a channel (meandering red curves) crosscut by afault (downward dark diagonal curve).

■■A simple basemap. Combining all the mappable elements into one visualizationworkspace, the status basemap shows horizon time data and faults from the geophysicist,overlain by well data, cross-section traverses and contours generated by the geologist.

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Thus by employing either the Voxel-pickingtechnique or the ASAP Automatic SeismicArea Picker application, a continuous hori-zon, perhaps interrupted by faults, is inter-preted. At the same time as the interpretationof the horizons, the faults can also be inter-preted. The traditional way of interpretingthem has been to just place the fault seg-ments on the seismic data wherever theyappear, or to interpret them directly on thestatus map by putting in boundary markers toshow where the displacements of the faultsfall. But, with this new software system, a cor-relation map can be generated to highlightheterogeneities based on seismic traces andto visualize the fault pattern automatically.

The correlation map is created by using spe-cific correlation parameters either based onan interpreted horizon surface or a slice from

the 3D seismic volume (previous page, topright). Strong changes suggest the location ofeither a fault or stratigraphic variance, andgenerally show the fault patterns clearly. Nointerpretations are needed to produce the cor-relation map, which is simply extracted fromthe seismic data ahead of time.

Considerable time can be saved at this pointby using several shortcut tools that havereplaced traditional methods. The geophysi-cist can apply, for example, the global cursortracker, the ASAP module, the conventionaltracker, and correlation maps not only tointerpret the fault boundaries and match thefaults to the reservoir edges, but to build up atime interpretation with an accurate fault pat-tern interpretation for a specific horizon.

Looking for closure of the event in question,the geophysicist would probably make a first-

pass structure map of that particular level (previous page,bottom). With it, it may be pos-sible to determine if a reservoir is likely to be astratigraphic, structural or combination trap.

In many cases, a time-structure map doesn’treveal this much information, only wherethere are potential highs toward which oil orgas is likely to migrate. Much more informa-tion can be gained from seismic attributes.Thus, the geophysicist would now run a quickattribute analysis on the structure map to lookfor amplitude variations, acoustic impedanceor volume attributes, which could be associ-ated with hydrocarbon accumulation. Theattributes indicate areas of higher porosity andpossible presence of hydrocarbons, and thisinformation will help determine whetherthere is remaining potential that may merit sit-ing a new well (below).

■■Attribute mapping. This multiwindow environment displays various time interpretation grids alongside surface-based attributes suchas reflection strength (left panels) and acoustic impedance (right panels) of a faulted reservoir. The ability to view and interpret thesediverse data types simultaneously increases the confidence in the overall interpretation result.

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Consistent and realistic interpretation ofboth horizon and fault surfaces requiresthree-dimensional visualization in theGeoViz application. For the faults specifi-cally, the interpreter faces the challenge ofderiving a geometrically correct and inter-nally consistent fault framework in the short-est timeframe. This task is performedautomatically by the Framework 3D applica-tion, allowing construction of an accuratelyterminated fault framework into which theinterpreter feeds the surfaces and has themterminated against the faults. (It dispenseswith the idea of defining polygons to showwhere the faults terminate.) If, for example, afault is encountered, the horizons will halt atthese barriers and then adopt values down

the fault plane. The result is an accuratelyterminated horizon at the fault intersection.

That done, the structural surfaces are incor-porated into the GeoViz 3D workspace, andattributes, such as acoustic impedance, arethen draped on top of those surfaces to showwhere the high energy or bright spots lie(above). This completes the time interpreta-tion of the surfaces, but to drill a well or doa simulation of the reservoir, the well plan-ning engineers need to have the surfacesconverted to depth. For that, the geophysicistemploys the InDepth application, a compre-hensive, interactive depth-conversion mod-ule with all the tools to generate andcalibrate velocity and depth models withwell and seismic data.

Depth conversion based only on well dataresults in considerable guesswork betweenwells, so it is often better to have the stack-ing velocity as well. In our example situa-tion, the geophysicist has only well data, butif stacking velocities were available, theyshould be calibrated and matched to thewell data. The interpreter would then select aseries of velocity functions, whether intervalvelocities or average velocities, and apply itall the way down to the zone of interest.Once the depth-converted surfaces wereestablished, the geophysicist could convertmany of the faults and all of the seismic datadirectly to depth and use that new depthinformation in the last stage of the interpre-tation, design of the well path in depth ratherthan in the time domain (next page, top).

Drilling targets are defined based on thesedepth-converted data, and proposals aremade for the well paths to reach those tar-gets. The targets and well-path designs arethen forwarded from the well-planning engi-neer member of the asset team to the geo-physicist, who loads them into the system tosee how they fit in the now centralized (geo-logical, petrophysical and geophysical) geo-logical model. If the proposed well meetsboth the E&P objectives and well engineer-ing constraints, the decision is likely to be todrill. If not, the target selection and wellplanning process require another iteration,until all asset team members are satisfiedwith the well proposal and agree on an opti-mal well plan. The result would be a wellwith the highest probability of success, onethat maximizes the return on the investmentat the lowest possible drilling-engineeringrisk (next page, bottom).

The GeoFrame 3.0 system accomplishes indays what once took weeks, and does sobecause of its streamlined interdisciplinaryworkflow and shared project database.Interpreters, geologists, petrophysicists, geo-physicists and engineers—as members of anasset team or as individuals—access thesame project data and participate in a cross-discipline, real-time interpretation orprospect evaluation. Although presentedhere as a somewhat linear process for thepurpose of simplicity, the workflow is neitherlinear nor circular, but instead, an iterative,concurrent process of interpretative contri-butions from members of a project assetteam who simultaneously view, edit andinterpret data and results throughout everyphase of a project. Each person’s work isbroadcast to the project database, whichthen transmits changes to everyone who isworking on the project as real-time updates.

■■Reservoir characterization. Many elements are used to characterize the reservoir in 3D,such as horizon surfaces, well logs, interpreted fault planes as well as the acousticimpedance subvolume shown here. The display shows where the higher porosity zone issituated (red). The large anomaly (red-white colors) highlights a gas play and permits amore accurate well-path design.

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Coming Applications and FunctionsWhen well-planning engineers receive thefinal depth-converted interpretation from thegeophysicist, the project exits the system. Inlate 1998, the GeoFrame 3.5 system will bereleased, which will add further integratedfunctionalities to this software platform.

Formerly linked but unincorporated, the CPS-3, StrucView and Framework 3D applicationswill be added as fully integrated componentsof the system. The CPS-3 gridding and con-touring application for E&P operations willextend surface modeling, volumetric analysisand mapping capabilities. The StrucView

module will add to structural interpretationwith its dip data description. And theFramework 3D application will make it pos-sible to leverage all the interpreted data in thegeophysical environment and map them, tovalidate faults against horizons, and createinfill maps between major seismic reflectorswithout having to resort to numerous macrojobs to accomplish this task.

The system will provide a platform forevery function from exploration throughdevelopment and production. It will seatintegrated applications for everythingrequired from the first undertaking in a reser-voir, whether shooting seismic lines ordrilling a well, all the way to the final simu-lation and even artificial lift. It will make vol-ume-based geological models in whichpetrophysical properties are distributed inrelation to seismic properties, and includesuch information as porosity, resistivity andsaturation. It will perform log-property map-ping and seismic inversion, but these func-tions are only the beginning; the workflowcommences well before and continues longafter geological and geophysical interpreta-tion, and so will the system’s capabilities.

Already, other oilfield disciplines are liningup for inclusion in the GeoFrame family. The Geco-Prakla SEISMOS seismic process-ing system, already compliant with the sys-tem, will soon be fully integrated. So, too,will the Drilling Office suite of drilling appli-cations, including the Anadrill PowerPlandirectional well-planning system, which isalready linked to the GeoViz application,allowing the well-planning engineer to seethe proposed wellbore path relative to tar-gets and key geologic structures as inter-preted by the geologists and geophysicists onthe asset team. When these are fully inte-grated into the GeoFrame environment,wellbore design time and expense will beconsiderably reduced.

Other functions, such as reservoir simula-tion and management, field operations anddrilling, and production data managementare being developed for inclusion in thefuture. Ultimately, the system will take itsplace as a solutions source, an informationinterchange and earth modeling toolbox thatseamlessly integrates petroleum exploration,development and production data manage-ment and utilization for faster, more efficientoperations with minimum risk. —DG

■■Depth conversion. The InDepth application allows accurate depth conversion of horizons and faults as well as the entire seismic volume. Because of tightly integrateddepth-conversion tools, it is possible to step from time to depth seamlessly. The left panel represents velocities that are used to convert the seismic horizon from time todepth. Lower velocity is red; higher velocity is blue. The right panel shows the same horizon with velocity control points displayed.

■■Designing well paths. GeoViz 3D visualization greatly expedites the design of well trajectories (red) to tap target zones in the most efficient manner while avoiding collisions with other wellbores.