Objective
The Badhole ID & Repair Module enables users to flag and repair washout for the bulk density, neutron, sonic, and photoelectric factor curves based on user criteria. This module also comprises options for flagging coal and salt and for de-spiking curves.
Key Parameters
For the badhole flagging the user should first specify what curves should be flagged (by well), then what criteria should be used (by well), and finally what the threshold values are (by zone).
- Flag badhole for RhoB and PE: Specify if badhole should be flagged for the bulk density and photoelectric factor curves, based on the specified criteria.
- Apply caliper max criterion: Flag badhole for RhoB and PE using a maximum threshold for the caliper curve.
- Apply caliper rugosity max criterion: Flag badhole for RhoB and PE using a maximum threshold for the caliper rugosity curve.
- Apply RhoB min criterion: Flag badhole for RhoB and PE using a minimum threshold for the bulk density curve.
- Apply RhoB max criterion: Flag badhole for RhoB and PE using a maximum threshold for the bulk density curve.
- Apply Drho max criterion: Flag badhole for RhoB and PE using a maximum threshold for the density correction curve.
- Apply PE max criterion: Flag badhole for PE using a maximum threshold for the PE curve.
- RhoB repair option: Specify the action to be performed when badhole is flagged for the bulk density curve.
- PE repair option: Specify the action to be performed when badhole is flagged for the photoelectric curve.
- Flag badhole for Nphi: Specify if badhole should be flagged for the neutron curve, based on the specified criteria.
- Apply Nphi max criterion: Flag badhole for the neutron curve using a maximum threshold.
- Apply Nphi min criterion: Flag badhole for the neutron curve using a minimum threshold.
- Nphi repair option: Specify the action to be performed when badhole is flagged for the neutron curve.
- Flag badhole for DT: Specify if badhole should be flagged for the sonic curve, based on the specified criteria.
- Apply DT max criterion: Flag badhole for the sonic curve using a maximum threshold.
- Apply DT min criterion: Flag badhole for the sonic curve using a minimum threshold.
- DT repair option: Specify the action to be performed when badhole is flagged for the sonic curve.
- Evaluate for coal: Specify if coal should be flagged based on specified criteria.
- Evaluate for salt: Specify if salt should be flagged based on specified criteria.
- Pad badhole flag: Specify if the badhole flag should be padded to include adjacent samples.
- Blend with repaired curve: Specify is the repaired curve should be blended with the original curve in intervals adjacent to the badhole flags.
Output Curves
Most important curves shown in bold.
- COAL_FLAG: Flag for coal intervals
- SALT_FLAG: Flag for salt intervals.
- BADHOLE: Badhole flag for bulk density.
- PE_BADHOLE: Badhole flag for photoelectric factor.
- DT_BADHOLE: Badhole flag for compressional sonic.
- NPHI_BADHOLE: Badhole flag for neutron.
- RHOB_FINAL: Final bulk density curve after all repair, de-spiking, and normalization.
- NPHI_FINAL: Final neutron curve after all repair, de-spiking, and normalization.
- DT_FINAL: Final compressional sonic curve after all repair, de-spiking, and normalization.
- PE_FINAL: Final photoelectric factor curve after all repair, de-spiking, and normalization.
CPI Config Reference
The relevant configuration file is 04_bad_hole.yaml.
Display
- Gamma ray and caliper track with caliper threshold parameter lines.
- Neutron-density track.
- Depth track.
- Caliper rugosity track with caliper rugosity threshold parameter lines.
- Density correction track with Drho threshold parameter lines.
- Density repair track with minimum and maximum threshold parameter lines.
- Neutron repair track with minimum and maximum threshold parameter lines.
- Sonic repair track with minimum and maximum threshold parameter lines.
- Photoelectric factor repair track with minimum and maximum threshold parameter lines.
Associated cross-plots
None.
Associated maps
- Badhole_summary: Thickness of density washout on a zone-by-zone basis.
Recommendations
- When working across large areas consider using caliper rugosity instead of caliper to identify badhole as caliper will vary based on well design.
- When flagging coal and salt use the check boxes in the zonal parameters to turn on the flagging for each zone as required.
- Repair via MLR (multi-linear regression) or RF (random forest) uses and auto-ML that builds and tests several combinations of models to perform an optimal repair.
