БУРМАСТЕР PRO · ENEngineering analysis of drilling
Distinguish rock-cutting rate from stage duration and compare intervals without causal shortcuts.
Prerequisites: SI units, MD/TVD, ratios and reading time logs.
Original learning material. Independent domain and translation reviews are pending. Not accredited training, an operating instruction or work authorisation.
Open interactive studyCHAPTER 1ROP, time and the correct denominator
A rate only has meaning with its time definition. Actual drilling time, on-bottom time and elapsed stage duration may be different quantities. Before calculation, identify which events the log includes: connections, circulation, surveys, repair and waiting. Do not silently exclude inconvenient intervals or classify every difference as non-productive time; categories depend on the agreed accounting system.
Across intervals, a time-based average is total drilled length divided by total time in the same category. An arithmetic average of interval rates generally differs because durations differ. A short fast interval next to a long slow interval makes this distinction important.
Before comparing shifts, tabulate interval boundaries, drilled length, selected time, bit condition, lithology, operating state and record source. Check time completeness and consistency before calculating. Better ROP does not establish shorter construction time or lower cost: casing work, logistics and delays can change the overall result.
Walkthrough
Interval A: 30 m in 2 h; B: 10 m in 2 h. Rates are 15 and 5 m/h; combined rate is 40/4 = 10 m/h. If B takes 1 h, the combined rate is 40/3 ≈ 13.333 m/h, whereas the arithmetic mean is (15+10)/2 = 12.5 m/h.
Independent task
18 m are drilled in 1.5 h, then 20 m in 2.5 h. The full stage lasts 6 h. Find combined drilling and elapsed-stage rates. What must be clarified about time categories?
Reveal debrief and criteria
38/4 = 9.5 m/h and 38/6 ≈ 6.333 m/h. The remaining two hours cannot be classified without log events. Both results use the same footage but different time definitions.
- Lengths are summed
- denominators are distinguished
- units are stated
- time is not classified without evidence.
Editorial criteria; independent assessment and learning-outcome validation are pending.
Attempt in the interactive worksheet →
CHAPTER 2Parameters, response and causality
Weight on bit, rotational speed and flow operate within a coupled system. A change in ROP cannot be explained by one parameter without rock, bit wear, cleaning and drillstring dynamic context. Record the control change, measured response and concurrent condition changes separately.
A trend shows co-variation but does not automatically identify mechanism. If ROP rises after RPM increases while a different formation is entered, the rotational contribution is not isolated. Torque oscillation amplitude alone does not identify a particular vibration mode: frequency, measurement location, signal quality and additional indicators are needed.
Build the learning analysis as a testable hypothesis. State the timed observation, alternative explanations and the evidence that could distinguish them. Actual parameter changes require the well programme, equipment limits and responsible authority. This chapter teaches interpretation, not field setpoints. A favourable numerical result with unknown constraints is not an operating recommendation.
Walkthrough
ROP rises from 12 to 15 m/h: observed growth is (15−12)/12 = 25%. This describes the change, not proof that one parameter caused the entire 25%.
Independent task
ROP rises from 8 to 12 m/h after two parameter changes and entry into another interval. Calculate growth, identify three confounders and formulate a testable hypothesis.
Reveal debrief and criteria
Growth is 50%. Possible confounders include lithology, bit condition and cleaning/dynamics. A hypothesis specifies a comparable interval and required measurements rather than claiming an established cause.
- Growth uses the original baseline
- alternatives are identified
- the hypothesis is testable
- no real operating parameters are prescribed.
Editorial criteria; independent assessment and learning-outcome validation are pending.
Attempt in the interactive worksheet →
CHAPTER 3Stage efficiency and improvement priorities
Team performance analysis needs agreed time categories. Separate actual drilling, planned activities, confirmed delays and unallocated intervals. The last category matters: unknown time must not automatically be attributed to human error or equipment failure. Categories must reconcile to the observation window.
Cost comparison requires a common boundary. Rig hourly cost, bit cost and total operation duration belong to different model elements. Faster drilling may accompany extra wear, tool changes or supporting expenditure. State included costs and distinguish a fictional estimate from an accounting fact.
Sensitivity helps prioritise improvement. How much could stage duration fall if ROP increased while other times stayed fixed? This gives a conditional effect under stated assumptions. It excludes operation interactions, complication probability and safety changes. Use it to formulate questions and select evidence, not to promise savings to a customer.
Walkthrough
120 m at 10 m/h takes 12 drilling hours; at 12 m/h it takes 10. With other activities fixed at 8 h, stage duration falls from 20 to 18 h: 10%, despite a 20% ROP increase.
Independent task
A 90 m interval is planned. ROP changes from 9 to 12 m/h; other activities take 6 h. Find durations, time reduction and forecast limitations.
Reveal debrief and criteria
16 and 13.5 h; reduction is 2.5 h or 15.625% of the initial stage. Other times and consequences are assumed unchanged; monetary savings are not determined.
- Stage boundary is preserved
- drilling and other times are separate
- percentage baseline is stated
- limitations are identified.
Editorial criteria; independent assessment and learning-outcome validation are pending.
Attempt in the interactive worksheet →
CAPSTONECapstone: an improvement report
A team compares two fictional intervals. A drills 60 m in 6 drilling hours plus 4 other hours. B drills 60 m in 4 drilling hours plus 6 other hours. Both bit and lithology change on B. A manager proposes calling B “50% more efficient”.
Check which metric the percentage describes and what changed in total duration. Produce a short engineering report with inputs, both rates for each interval, confounders and requested evidence. Do not prescribe parameters or attribute effects to personnel or equipment without evidence.
Walkthrough
Start by defining the stage boundary and time categories. Check percentages against the original metric.
Independent task
Calculate drilling and elapsed rates for A/B; assess the manager’s claim; identify evidence needed for causal analysis.
Reveal debrief and criteria
A: drilling rate 10 m/h, elapsed rate 6 m/h. B: 15 m/h and 6 m/h. ROP rises 50%, while total duration remains 10 h. Overall “efficiency” is undefined; costs and causal contributions are unknown. Comparable intervals, time categories, bit condition, rock, parameters and log quality are needed.
- All four rates are calculated
- percentage baseline is stated
- correlation is not treated as causation
- the report includes limits and evidence requests.
Editorial criteria; independent assessment and learning-outcome validation are pending.
Attempt in the interactive worksheet →