Glossary

Plain-language definitions of the terms used across Tidywells, with links to the posts where they matter.

A B C D E G H I L M N P Q S V W Y

Arps decline curve: A family of equations, first described by J. J. Arps, that describe how a well's production rate falls over time. Tidywells uses the hyperbolic form with a switch to exponential decline at a terminal rate. See the decline-curve tool and the backtest.
b-factor: The curvature parameter of an Arps curve. b = 0 is exponential decline, b = 1 is harmonic, and values between 0 and 2 are common in practice. A higher b means the decline slows down more over time and gives a larger long-term forecast, so very high values deserve caution.
Backtest: Testing a forecast method on the past: fit it on a well's early months, predict the following months, and compare with what was reported. Our backtest did this for about 1,900 wells.
BC Energy Regulator (BCER): The regulator for oil and gas activity in British Columbia. Tidywells reads its public production file for BC.
Bitumen: A heavy, viscous form of oil produced mainly in northern Alberta. In the regulator files, Alberta wells licensed for crude bitumen are part of the oil product, which is why "Alberta oil" totals include them. See Most licensed wells aren't producing.
Cumulative production: The total volume a well has produced since it started, or the total volume a forecast adds up to over a period.
Decline curve: A line that shows how a well's production rate falls over time, used to forecast future production. See the tool.
Di (initial decline): The starting decline rate of an Arps curve, written as a share per year. A Di of 0.7 means a nominal 70% per year at the start. It is nominal, so it is not the same as the actual fall over one year.
Dmin (terminal decline): The long-run decline rate at which a hyperbolic curve is switched to exponential decline, so the forecast does not flatten forever.
Energy basis: A way to compare oil and gas on one scale. Tidywells counts 6 Mcf of gas as equal to 1 barrel of oil, and calls a well an oil well if oil is at least half of its output on this basis.
Gas-oil ratio (GOR): How much gas a well makes for each barrel of oil, in standard cubic feet per barrel (scf/bbl). It differs a lot between provinces and well types. See Gas-oil ratios.
Horizontal well: A well drilled sideways through the producing layer after its vertical section, which exposes more rock. Most new wells in Alberta are horizontal. See Are new wells getting better?
Infrastructure file: The regulator's list of wells with details such as status, licence and spud date, separate from the production file. Its row count is not the number of wells. See What a naive load gets wrong.
Licensee: The company named on a well's licence. It is not always the current operator, because wells change hands without a new licence. See How concentrated is production?
m³ and 10³ m³: Cubic metres, the unit the regulators use. Oil is reported in m³ and gas in thousands of m³. Tidywells converts at 6.2898 barrels per m³ of oil, and about 35.3147 thousand cubic feet (Mcf) per thousand m³ of gas.
Mcf and MMcf/d: Mcf is a thousand cubic feet of gas and MMcf is a million. MMcf/d is a million cubic feet per day, the unit for gas rates on this site.
Median: The middle value when results are sorted, so half are above it and half below. Tidywells uses medians for per-well results because a few very large or very small wells would distort an average.
Monthly snapshot: A Tidywells page for one month with the average daily rate, change on the month before and on the year before, and the number of wells producing. See the list of snapshots.
NPV (net present value): Future cash flows from a forecast, discounted back to today's dollars. In the decline-curve tool it is illustrative only and is not a valuation.
Petrinex: The system that publishes public production and well data for Alberta and Saskatchewan. Tidywells reads those public files and does not host them.
Producing well: In Tidywells analyses, a well that reported a positive oil or gas volume. A licensed well that is abandoned, suspended or idle is not producing. See licensed vs producing.
qi (initial rate): The production rate at the start of an Arps curve, in barrels or thousand cubic feet per day.
scf/bbl: Standard cubic feet of gas per barrel of oil, the unit of gas-oil ratio.
Seasonality: A regular pattern that repeats through the year. Gas production in Alberta and BC runs above trend in winter and below in late spring and autumn, while oil barely moves. See Gas has a season.
Shut-in: A well that has stopped producing, temporarily or for longer. Production files only show wells that produce, so a shut-in simply disappears from the data. See Shut-ins and restarts.
Spud date: The date drilling of a well began.
Vintage: The year a well started producing, used to compare newer and older wells. See Are new wells getting better?
Well status: A field in the regulator's well file describing what state the well is in, such as flowing, pumping, suspended or abandoned. It can be blank, and some wells with a blank status do produce.
Year-on-year change: A comparison of a month with the same month a year earlier. It avoids the effect of the season, which a comparison with the previous month does not.

Informational only, not investment, legal or engineering advice. Missing a term? Email hello@tidywells.com.