Reserves and Forecasting · Module R5
Type Wells and Undeveloped Locations
Forecasting wells that have not been drilled. The module covers analog selection, normalising for time zero and completion size, why an average curve is not the median well, how survivor bias inflates late-time averages, and what evidence and commitment undeveloped reserves require.
- Level
- Intermediate
- Position
- Module 5 of 8
- Video
- About 18 minutes, narrated
- Format
- Narrated video lesson with captions and slide reading view; with the certified option, a quiz whose pass unlocks the next module.
What the module covers
- Selecting and normalising analog wells
- Mean well versus P50 well
- Survivor bias in month-by-month averages
- Lognormal EUR statistics and analog count
- Proved undeveloped locations and the five-year guideline
Learning outcomes
After the module you should be able to:
- Build P90/P50/P10 type wells from a documented analog set.
- Build P90, P50 and P10 type wells from an analog set
- Quantify how uncertain a small-sample P50 is
- Decide which locations can carry proved undeveloped reserves
A short preview
Well results in a play are usually right-skewed, so the mean sits above the median. If the natural logarithm of EUR has a standard deviation of 0.5, the mean of a lognormal distribution is the median multiplied by e^(0.5²/2), about 13 percent higher. A type curve built by averaging rates month by month therefore describes the mean well; scale a representative shape to the median EUR when you want the best-estimate well for a single location.
Who it is for
Reservoir and production engineers, petrophysicists and geoscientists who estimate, review or report reserves and production forecasts.
Prerequisites: None required; working familiarity with production data and volumetrics helps.
Take the module in the Learning Hub
Reserves and Forecasting: Specialty course, sold separately: eight modules from PRMS classification and decline curves to type wells, material balance, aggregation and the reserves report. The lesson opens in the Learning Hub once the track is purchased; graded quizzes and the certificate come with the certified option.