Digital Well Logs - ClickDimensionsfiles.clickdimensions.com/.../tgsgps-digitalwelllogs_a4jul2015.pdf · Over eight million well logs in over thirty countries make up ... Digital

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Largest Online DatabaseOver eight million well logs in over thirty countries make up TGS’ collection of digital well log data from the most popular hydrocarbon plays around the globe.

Depending on customer project needs, the digital formats available for each well log range from depth-calibrated smartRASTER® image files to completely digitized LAS and LAS Plus curve suites. Each format can be conveniently accessed online, through the online well data portal LOG-LINE Plus!®

Quality, Completeness and GrowthTGS adheres to strict quality control standards when acquiring, scanning, digitizing and processing well data. When possible, TGS sources the original hardcopy or truck data, and the collection includes only complete curves and log runs. TGS continuously invests in the growth of the collection, infilling regions where there is existing data, expanding into new countries and upgrading the existing collection to higher-value formats.

Digital Well LogsAll data can be delivered as:

� Hardcopy

� Raster image logs (.TIFF)

� smartRASTER® depth-calibrated rasters (.SIF)

� Digital LAS curves (see reverse for spec details)

� Source-error corrected and standardized LAS Plus digital curves

Access, Order and DeliveryData can be ordered directly online and downloaded immediately (if available) or can be shipped on physical media per preference or the size of the order. A user account is required to access the online well database. TGS also has a number of different access plans tailored to meet the cost and data requirements of a large variety of exploration ventures.

Global Well Log Coverage

US Tel: +1 713 860 2100

Email: [email protected]

For more information, contact TGS at:

UK Tel: +44 208 339 4200

© 2015 TGS-NOPEC Geophysical Company ASA. All rights reserved.

See the energy at TGS.com

Well Integrity Validation � Well information such as API/UWI number, operator, well

name and well number will be verified for accuracy

� Logs will be checked for quality and coverage before digitizing

Data Capture � A standard LAS file will consist of one gamma ray,

spontaneous potential, caliper, resistivity (shallow, medium, and deep) sonic, and density (bulk, correction, and neutron/density porosity, PE).

� TGS digitizes Wireline Standard curves only in onshore wells.

� Additional logs such as mud, micro, and dipmeter are considered non-standard but can be added upon request for an additional charge.

ResistivityThree curves from a Resistivity Log will be processed – “Shallow, Medium and Deep Resistivity”

Data Processing � Data values in casing will be removed (except GR and

NPHI)

� Data values below first reading will be removed

� -999.25 will be inserted for all removed data values

� Negative values on resistivity will be set at .0004

� Negative values on GR will be clipped to 0

� Negative values on DT will be clipped to 0

� Curves with the same curve name/description will be merged into one continuous curve covering the entire depth available

� Curves with different curve names (AIT 90, AOI 90) will not be merged

� In case of overlapping runs, shallower runs at first reading will be merged to subsequent deeper runs

� All processed curves will retain the original logging contractor mnemonics

� Header information will be captured for the last run

� All LAS is subject to a rigorous quality control process including multiple steps to ensure both complete curve coverage and a match between the digits and the hardcopy image

Final Data Output � LAS file will be output in LAS version 2.0

� All raw LAS will be output at .5 samples per feet unless metric which will be output at .1 samples per feet.

� Log header parameters and information will be provided in the LAS file for the last run available.

� Data delivery is available on CD, DVD or via FTP/Internet.

Digital Well Log Processing – LAS

LAS Coverage Map

SonicAll sonic curves are processed.

FDC/CNL

One of each of the shared curves (GR, Cali and SP) in priority as follows:

Curve Type Range Example Comments

Shallow ~10”, 20” ASN, AT 10, ASFL

Medium ~30” ILM, AT30

Deep ~60”, 90 ILM, AT90

Deep ~8’, 18’ LAT Digitize all LAT curves

Curve Type Example Comments

Bulk Density RHOB, RHBB... Take regardless of logscale

Density Correction DRHO, CORR, DRBB...

Neutron Porosity NPHI, NPOR, CNC, CNF...

Density Porosity DPHI... Take regardless of logscale

Curve Type Digitizing Priority #

Most Continuous Res. FDC/CNL Sonic Shallow

Gamma Ray ”GR” 1 4 2 3 1-Digitize the most continuous

curve

2-Infill missing data from next

priority logCaliper ”Cali” 1 4 2 3 Same as above

Spontaneous Potential ”SP” 1 2 4 3 Same as above

Curve Type Example

Delta ADT, DTL...