Gamma Ray
The gamma ray sensor is primarily a lithology indicator. It measures the natural gamma ray radiation that is emitted from naturally occurring radioactive elements (uranium, thorium, potassium) deposited within the surrounding formations. Shales generally contain higher amounts of these radioactive substances than sandstones and carbonates (limestone and dolomite). Therefore, the gamma ray sensor can in most cases, effectively 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)
Drilling Dynamics
The log response of these measurements varies widely depending on drilling circumstances and are beyond the scope of this manual. Refer to the DDG Users Manual, Drilling Assistant, and EWD documentation for interpretation guidelines.
Other Requirements for This Service
None.
Log Quality and Data Management Standards Drilling Dynamics
Log Presentation
North and South America Log Presentations
1:600 AND 1:1200 ENGLISH DEFAULT LOG FORMATS (correlation)
1:240 ENGLISH LOG FORMAT
1. TVD: Optional trace used specifically for horizontal well applications. Scale should increase from right to left.
2. TCDX: Optional trace. Scale should increase from left to right.
3. INC: Optional trace. Scale should increase from left to right.
4. RPMS: Optional trace. Scale should increase from left to right.
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
Drilling Dynamics Log Quality and Data Management Standards Plotting Recommendations
Foreground logs configured during the job should use a 2 inch depth scale.
Final logs are presented with a 2 inch and 5 inch scale.
Scales
For surface and true torque, choose trace bounds that allow the downhole and surface traces to track close together. These are subtle changes
between surface and downhole parameters that can be identified. Although these trace bounds are typically different, the track divisions must be the same.
For example: Surface Torque = 5000 to 20000 ft-lbs.
True Torque = 0 to 15000 ft-lbs...each division for both scales is equal to 1500.
For true and surface weight on bit, trace scales should be the same.
Traces
Always use medium dashed lines for downhole data (true torque and weight on bit).
See “Annotations” on page 5-10.
Log Quality and Data Management Standards Drilling Dynamics International Log Presentations
1:500 METRIC DEFAULT LOG FORMAT (correlation)
1:200 METRIC LOG FORMAT (quantitative)
1. ROPS: Default units are ft/hr. Other default units and scales are 100 - 0 m/hr, 60 - 0 min/ft, 60 - 0 min/m, 10 - 0 ft/min, 10 - 0 m/min. Default for averaging is also feet. Metric equivalent is 2.0 (for 1:500) and 1.0 (for 1:200).
2. TCDX: default units are Celsius. Other default units and scales are 0 - 250°°F.
3. TVD: Optional trace used specifically for horizontal well applications. Scale should increase from right to left.
4. INC: Optional trace. Scale should increase from left to right.
5. TQCX/TQCS: Default units are ft-lbs. Optional units and scales are 0 - 20000 KN-m.
6. WBCX/WBCS: Default units are K-lbs. Optional units and scales are 0 - 50 Tonnes, 0 - 500 KN.
7. RPMS: Optional trace. Scale should increase from left to right.
Note: Pen up intervals are in feet. Metric equivalent is 3 meters (for 10 feet) and 30 meters (for 100 feet).
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
Drilling Dynamics Log Quality and Data Management Standards Plotting Recommendations
Foreground logs configured during the job should use a 2-inch depth scale.
Final logs are presented with a 2-inch and 5-inch scale.
Scales
For surface and true torque, choose trace bounds that allow the downhole and surface traces to track close together. These are subtle changes
between surface and downhole parameters that can be identified. Although these trace bounds are typically different, the track divisions must be the same.
For example: Surface Torque = 5000 to 20000 ft-lbs.
True Torque = 0 to 15000 ftlbs...each division for both scales is equal to 1500.
For true and surface weight on bit, trace scales should be the same.
Traces
Always use medium dashed lines for downhole data (true torque and weight on bit).
Annotations
• If you are plotting final logs on a replay station with a standard three track plotter (Gulton plotter), you are restricted to a three-track presentation. Most "during the run" remarks can be annotated directly on the log provided the remarks are not lengthy and they do not overlap log traces. Pre- and post-run remarks should be provided in the Remarks page of the Main Header. Realtime zeta logs can utilize track IV for annotations.
• All of the information on DDG provided above was taken from the Drilling Dynamics Field Operations Manual. It is required that a copy of this manual be obtained before running the DDG Service.
At the beginning of each run, list the following:
• Teleco run number and depth interval.
• Client bit number.
• Bit make, model, size, TFA, grading in (i.e., re-run), IADC code.
Log Quality and Data Management Standards Drilling Dynamics During the run, note the following:
• Reaming on connections (be sure to note the frequency and reason for reaming).
• Drag on connection.
• Mud weight changes with explanations for the change.
• RPM ranges.
• Surface weight on bit changes.
• Pump stroke rate and change.
• Rotary or oriented drilling.
• Geologic horizons.
• Explanation of log events as they occur.
At the end of each bit run, note the following:
• Reason for pulling out of the hole.
• Note any reaming hole conditions.
• Bit grading.
• Wear on the stabilizers.
Drilling Dynamics Log Quality and Data Management Standards
Chapter