Gamma Ray
Tool size, hole size, mud weight, %K (potassium content), sensor type, gamma API correction factor.
Dual Propagation Resistivity
Tool size, hole size, resistivity of the mud Rm, and constants (base offsets and temperature characterization constants).
Modular Neutron Porosity
Tool size, hole size, mud density, borehole salinity.
Modular Density Lithology
Tool size, hole size, mud density.
Data Editing
Editing of Realtime Data
Editing of realtime MNP data is not permitted. The realtime formation records are needed to accurately assign depths to the memory data. In the event severe decoding problems exist and the quality of the MWD log is lowered, editing is allowed provided the logging engineer has consent from the customer. In this case, the logging engineer is required to notify the Teleco office, then notify the client and request consent to edit the MWD log. If editing takes place, the engineer shall maintain a separate copy of unedited raw data that he shall use for processing memory data. Any and all editing should be prudent. If data is edited, it should be removed from the database. Under no circumstances should the data be replaced or
Log Quality and Data Management Standards Triple Combo altered. It is preferred that questionable data remain in the database. This data should be identified and referenced on the log as such with a remark.
Editing of Memory Data
This is strictly prohibited. There are several reasons for this. We should let the client decide whether the data in question is useful to him or not. It is our job and responsibility as logging engineers, however, to identify data that is most likely in error (for whatever reason) and documenting this as such on the log. If the client requests an edited memory log with suspect data removed, a separate log should be made and documented as such. The LIS tape should contain all of the original memory data.
When an interval of questionable data is recorded and identified, the client should be notified and a relog should be recommended. The concept of re-logging a particular interval to determine the repeatability of logging sensors is a standard practice in the logging industry. In order to establish repeatability, it is important to relog a zone where the log response is not in question in addition to relogging the questionable zone. Discuss this with the client. If the client declines to relog the interval, document this as well as the questionable interval on the remarks page of the log.
Depth Shifts
Make sure logging depths are as accurate as possible. This is crucial for this service. Make depth shifts in the database where necessary. Anytime depths differ at a depth at kelly down by 1.0 foot (0.45 meters) or greater, a depth shift should be performed. Depth shifts can be minimized by
frequently calibrating the Kelly Height sensor at kelly down and updating the depth at kelly down at every connection.
Data Management
M-SERIES
A raw database file should be stored on the hard disk (Winchester) and a raw file backed up to disk. In the event that editing of the MWD data occurs, a copy of raw unedited data shall be maintained for processing memory data (see “Data Editing” above). If a Winchester is not used on the rigsite, a raw database file also should be backed up to disk. Provide all necessary information on every disk label, and use an easy to follow sequential numbering scheme for labeling disks.
Triple Combo Log Quality and Data Management Standards MDMS
Two file types need to be backed up to disk. These are the raw memory dump data and the XFER file. Both of these need to be backed up on a run by run basis.
P-SERIES
The database file should be backed up to tape periodically during the job.
Both edited and raw data are maintained in the same database so there is no distinction between the two like M-SERIES.
HPUTIL
When M-SERIES (MWD data), MDMS XFER files (RWD data), or P-SERIES XFER files (MWD or RWD data) are converted to binary files for plotting with MPLOT, then several file types should be backed up to disk. These are as follows:
• binary.* (includes .fil, .apd, .uni, .idx),
• *.cfg (HPUTIL Rev. 2.1 or greater)
• setup.fil (Mplot/Wplot formats...formally newplot.fil)
• log.fil (Makelog/Head/Minihead formats)
• tvddata.fil
• newplot.fil (use with HPUTIL versions earlier than Rev. 2.1)
• header.fil (use with HPUTIL versions earlier than Rev. 2.1)
• comment.fil
These files can be compressed using PZIP and backed up to disk using FASTBACK with the program Getdata (see “Getdata Disks” on page 1-4).
Rigsite Data Processing
Smoothing and/or Averaging M-SERIES
None applied to the database. User selective smoothing or averaging can be applied when plotting (see log formats for recommended curve
smoothing).
Log Quality and Data Management Standards Triple Combo MDMS
MDMS processes raw memory dump data with MWD data and creates an XFER.FIL. Use MPLOT Utilities in HPUTIL to convert XFER file into a binary file. Run Squeeze to remove backplots and average data on a 0.25 feet (0.1 meter) interval (see “Squeeze” on page 9-6).
P-SERIES
None applied to the realtime database. User selective averaging (averaging on/off, it is recommended to select averaging). Propagation resistivities are block averaged on a 0.25 feet (0.1 meter) interval. See “Filtering” on page 9-5 for exclusive filtering routines applied to neutron porosity, density, and gamma ray data. During processing of data, backplots are removed.
Additionally, user selective smoothing or averaging can be applied when plotting (however, if the data is processed with averaging selected, it is not recommended to smooth during plotting).
HPUTIL
If Squeeze is applied to the binary.fil, backplots are removed and data is averaged on a 0.25 feet (0.1 meter) interval. Additionally, user selective smoothing can be applied when plotting with MPLOT (see log formats for recommended curve smoothing).
Filtering Despiking
Available only in P-SERIES 2.0 and above. Applied to density data prior to hanning window filter (see below).
Hanning Window Filter
Available only in P-SERIES 2.0 and above. Applied to density data after
"despiking." Also applied to neutron porosity and gamma ray data. This routine filters as the data is placed on a 0.25 feet (0.1 meter) interval.
Chi Square Smoothing
Available only in P-SERIES 2.0 or above. Applied to bulk density value using delta rho, two raw data values, and the density long space windows 4 and 5.
Triple Combo Log Quality and Data Management Standards Other
Borehole Corrections
Automatically applied by surface software (see “Borehole Corrections” on page 9-2).
Dielectric Corrections
Performed as required. This will be a rigsite option in P-SERIES 2.01 and above. Applied to phase difference and amplitude ratio resistivities when these data are affected by formation dielectric effects.
Squeeze
Squeeze is required for non-P-SERIES databases (HPUTIL binary files).
Apply to binary files before plotting final logs with Gulton plotters.
Squeeze compresses the data file by removing all backplots and then averages the data on a 0.25 feet (0.1 meter) average. (For more information, see “Squeeze” on page 1-5.)
Quicken
Quicken is not required but is highly recommended for non-P-SERIES databases (HPUTIL binary files). Apply to binary files after Squeeze is performed. This application sets up indices for every 100 feet (50 meters) of log, which speeds up the depth search routine for the MEDIT editor.
(For more information, see “Quicken” on page 1-5.) ADDTSD
ADDTSD is required for non-P-SERIES databases (HPUTIL binary files).
Apply to binary file as needed during job. This application calculates the time since drilled and data density curves for MWD and RWD data.
Calculate from the phase difference resistivity (RPCM) unless otherwise requested. (For more information, see “Time Since Drilled” on page 2-7.) ADDTVD
ADDTVD is required on every horizontal well. This routine calculates and arranges directional data (true vertical depth) so it can be plotted as a curve.
This is an HPUTIL utility program. (For more information, see “True Vertical Depth” on page 2-8.)
Quicklook WDS Log Analysis Performed at the rigsite as required.
Log Quality and Data Management Standards Triple Combo Note: No other rigsite data processing is required unless
incorrect or base offsets and temperature characterization data and/or incorrect borehole corrections have been entered into the database. If this occurs, enter the correct correction factors and
recalculate the database.
Postwell Data Processing
Before Final Logs Dielectric Corrections
Performed as required. Applied to phase difference and amplitude ratio resistivities when these data are affected by formation dielectric effects.
This can be performed either in P-SERIES 2.01 and above or WDS.
Inversion
Performed as required. Applied to phase difference and amplitude ratio resistivities when characterized by thin bed effects. Performed in WDS.
After Final Logs
Postwell WDS Log Analysis
Performed at clients request by Regional Log Analyst. Provides more detailed analysis of logging data than Quicklook.
LIS ASCII File and Tape
Performed in either MDMS, P-SERIES, LOGWORKS, or WDS at customer's request.
Rigsite Calibration Verification
Required at the beginning and end of each run. Verification accomplished using the density verifier and verification menu's in MDMS or P-SERIES surface software. P-SERIES records and processes verification data and automatically calculates the variance between the shop and rigsite verification. Verification data should be recorded on Calibration Verification page on P-SERIES header.
Triple Combo Log Quality and Data Management Standards
Quality Control
Quality Control Curves Data Density
Currently, data density is not calculated for neutron porosity or bulk density. Use the data density calculated from phase difference resistivity (RPIM). Data density (integrated) should be plotted on the quantitative log as tick marks in the depth track on the left hand side.
Time Since Drilled
Since there should be relatively little difference in the time between downhole sensors, use the time since drilled calculated from phase difference resistivity unless DPR is not present (due to failure, not in drillstring, etc.) or the client requests otherwise. This will maintain consistency between logs. Plot time since drilled as a medium spot line in track III on quantitative logs. A 0 to 300 minutes scale is recommended with no wrap or back up. Where the time since drilled curve goes off scale, provide a remark in the remarks page indicating the length of exposure time. Reference this remark on the log where the curve goes off scale.
Delta Rho (∆ρ)
This is a very important quality control curve for the density measurement.
This curve plots the amount of correction (in g/cc) which has been applied to the density measurement as a result of increasing standoff of the density detectors from the borehole wall. The correction compensates for the drilling mud in the annulus (between the detector and formation) and is largely dependent on mud weight and formation lithology.
Note: Delta Rho (∆ρ) corrections are positive for low mud weights but may be negative for high mud weights and carbonate lithologies.
The quality of the density data is considered
compromised with any correction greater than +/- 0.10 g/cc.
Log Quality Control
You are responsible as a logging engineer to periodically evaluate the data quality of your logs. Generate a quantitative log and inspect the curves for areas that might suggest a compromise in quality. If areas characterized by poor quality are detected, notify the office (Eastman Teleco) and the client
Log Quality and Data Management Standards Triple Combo immediately. Under these circumstances, the client should be given the opportunity to recover either lost or poorly recorded data.
Listed below are required log quality checks that need to be performed for any RWD service. If during these checks you identify a problem area, you are required to call the office for recommendations.
Note: Refer to DPR Services (see Chapter 7 "Dual Propagation Resistivity") for additional recommended DPR log quality checks. These log quality checks should be run in addition to the MDL log quality checks.
1. Realtime vs. Memory Data Comparison: A quantitative log is required for adequate evaluation. At the end of each run after the memory data has been processed, a log should be made with the realtime and memory data plotted side by side (i.e., realtime DP*X data in track II, memory DP*M data in track III [* = L, S, for limestone, sandstone, respectively]). The engineer should evaluate the log for depth shifts between the realtime and memory data. Depth shifts result when incorrect time offsets are applied before processing. If depth shifts are identified, call the office for recommendations.
Note: There may be a difference between the realtime and memory MDL log responses due to smoothing and averaging which is not applied to realtime data (see
“Rigsite Data Processing” on page 9-4).
2. Realtime vs. Relog Data Comparison
• A quantitative log is required for adequate evaluation. After a relog (second pass) is performed, it is important to plot the memory relog data with the "original pass" realtime data.
Plot realtime and memory gamma ray in track I and original pass realtime DP*X with memory relog DP*M in track II (plotting DPR data in track III is optional). Evaluate this data for depth shifts. If depth shifts are identified, call the office for recommendations.
• If memory relog data is merged with "on bottom" data, a composite log which contains the realtime "on bottom" data and the memory merged relog data should be plotted and evaluated for depth discrepancies. Plot the realtime "on bottom" and the memory merged relog gamma ray together in track I. Plot the realtime "on bottom" and the merged relog in track II (plotting DPR data in track III is optional).
Triple Combo Log Quality and Data Management Standards If depth discrepancies occur, call the office for
recommendations.
Typical Log Response
Gamma Ray
The gamma ray sensor is primarily a lithology indicator. It measures the natural gamma ray radiation which is emitted from naturally occurring radioactive elements (uranium, thorium, and potassium) deposited within the surrounding formations. As it turns out, shale generally contains much higher quantities of these radioactive substances than sandstones and carbonates (limestone and dolomite). Therefore, the gamma ray sensor can in most cases easily distinguish between shales and non-shale formations.
• Shales are generally identified by high gamma ray readings (greater than 100 MWD-API units).
• Non-shale formations (sandstones and carbonates) are identified by relatively low gamma ray readings (lower than 60 MWD-API units).
Dual Propagation Resistivity
After borehole corrections have been applied and relatively standard borehole conditions exist, the following relationships between Rpd and Rat
should apply.
Permeable Zones
When Rmf< Rw , then Rpd< Rat
When Rmf > Rw , then Rpd> Rat
In both cases, the amount of separation will depend on the depth of invasion, the relative values of Rmf, Rw , and water saturations.
Impermeable Zones (Shales) When Rmf < Rw , then Rpd≤ Rat
When Rmf> Rw, then Rpd≥ Rat
Dielectric Formations Rpd < Rat
Log Quality and Data Management Standards Triple Combo Thin Beds Intersecting Borehole at High Incident Angles
(Above 60°) Rpd > Rat
Eccentricity
Typically no effect unless a large contrast between Rm and Rtexists (either Rmmuch greater than Rt , or Rtmuch greater than Rm). Under these
circumstances Rpd< Rat. Modular Neutron Porosity
After borehole corrections are applied and the following relationships should apply. This also assumes the correct logging matrix (sandstone, limestone) has been applied.
Clean Reservoir Rocks Filled with Either Water or Oil
NPCM reads correct porosity and also reads the same as DPCM (density porosity).
Clean Reservoir Rocks Filled with Gas
NPCM reads lower porosity than DPCM (density porosity).
Shale Zones
NPCM reads higher porosity than DPCM (density porosity).
Modular Density Lithology
The following relationships should apply. This also assumes the correct logging matrix (sandstone, limestone) has been applied.
Permeable Zones
• Should read correctly unless significantly affected by standoff, drilling mud, and lithology (low mud weights will yield a positive ∆ρ; high mud weights and/or carbonates will yield a negative ∆ρ). The density measurement is considered
compromised with any ∆ρ correction greater than ± 0.10 g/cc.
• DPEM (photoelectric cross section) will read too high in barite loaded muds (over 12.0 ppg).
Triple Combo Log Quality and Data Management Standards Impermeable Zones
• Same as above.
• DPEM (photoelectric cross section) will read too high in barite loaded muds (over 12.0 ppg).
Other Requirements for This Service
Surface measurement of Rmand Rmf corrected for bottom-hole temperature (CDS temperature) required on a daily basis. This data should be supplied on the header of each daily log with BHCT (see “Main Header,
Environmental Parameters” on page 3-8 for measurement procedures).
Log Presentation
Log formats and trace scales for Triple Combo Services are more complex and diversified than our other services. Formats and scales can vary greatly from each client as well as each region. It is important to consult the client for preferred formats and scales prior to logging. The formats provided below are default formats. Two types of formats are listed: combined and segregated. Combined formats present all of the parameters measured by the DPR, MNP, and MDL on one log. This is the typical "Triple Combo"
format. Segregated formats typically present the resistivity traces on a separate log from the neutron porosity and density traces. Formats are additionally broken down by matrix type (limestone or sandstone). Since neutron porosity and density are typically run together, the log formats presented here are the same as those presented for modular density lithology.
Note: All log formats listed below assume the data is either realtime or memory data that has been processed without a P-SERIES system (or with a P-SERIES system "without averaging" selected for processing) and plotted using MPLOT. In cases where a P-SERIES system was used and the data was processed using the "averaging" option, then it is recommended not to smooth during plotting.
This will result in over smoothed logging traces. This will most frequently affect the Gamma Ray MWD API and Bulk Density/Density Porosity traces.
Log Quality and Data Management Standards Triple Combo North and South America Log Presentations
Combined Log Formats (Triple Combo)
Dual propagation resistivity, neutron porosity, and bulk density/density porosity are combined on the same log. For double combo logs, use these same formats with the exception of the missing trace or measurement.
Consult the client for preferred formats.
1:600 AND 1:1200 ENGLISH DEFAULT LOG FORMATS (correlation) LIMESTONE MATRIX
SANDSTONE MATRIX
Track 1: Linear Track 2: Linear Track 3: Linear
Trace Track Param Ledge Redge Line Mode Smooth Pen Up Notes
1
Track 1: Linear Track 2: Linear Track 3: Linear
Trace Track Param Ledge Redge Line Mode Smooth Pen Up Notes
1
Triple Combo Log Quality and Data Management Standards
1. TCDM: Optional curve for this presentation. Plot this trace in Track 3 if DPEM and/
or DRHM are not presented.
2. TVD: Optional trace used specifically for horizontal well applications. Scale increases from right to left.
3. DPLM/DPSM: Optional traces for these are BDCM (Bulk Density, Compensated).
Scales are 1.65 to 2.65 g/cc (for sandstone matrix), 1.95 to 2.95 g/cc (for limestone matrix). Consult client for preferred traces and scales.
4. DPEM/DRHM: Optional traces on correlation logs. These should be set up with half track presentations (left half, right half). Accuracy of DPEM diminishes significantly in drilling muds with high concentrations of barite (typically greater than 12.0 ppg).
This is currently not a commercial measurement.
1:240 ENGLISH DEFAULT LOG FORMATS (quantitative) LIMESTONE MATRIX
Track 1: Linear Track 2: 2 Cycle Log Track 3: Linear
Trace Track Param Ledge Redge Line Mode Smooth Pen Up Notes
1
Log Quality and Data Management Standards Triple Combo
SANDSTONE MATRIX
1. TCDM: Optional curve for this presentation. Plot this trace in Track 3 if DPEM and/
or DRHM are not presented.
2. RPTM/RPIM: As a default, use the time since drilled and data density from phase difference. The output of the RPIM trace is predetermined. However, a number must be put into these parameters to prevent MPLOT from crashing. Presentation for data density is in the depth track.
3. TVD: Optional trace used specifically for horizontal well applications. Scale
3. TVD: Optional trace used specifically for horizontal well applications. Scale