Operating schedules · in 1 model

Oil and gas reserves roll-forward

PD, PUD, 1P and 2P from one year to the next.

By Surojit Chakraverti, founder of L3VLUP and an investor running a long-short healthcare and technology equities strategy.

On this subject: oil and gas reserves roll-forward.Updated 5 November 2026

Part of project finance and infrastructure models, with the models, labs and guides around it.

What it does

The reserves a producer reports each year, and why they move. Proved developed (PD) reserves fall with production, move with price revisions (price sets when a producing well stops being economic) and rise as drilling converts undeveloped locations. Proved undeveloped (PUD) reserves are locations booked times the EUR of a well; drilling one moves its EUR from PUD to PD, which leaves 1P unchanged, and extensions book new locations upgraded from probable. Probable reserves added to 1P give 2P. Reserve life is closing reserves over the year’s production, and the reserve replacement ratio is reserves added over reserves produced.

Where it lives

The same schedule in each model that carries it, with the rows to open. Open a model in the browser, go to the sheet, and click the lines.

Upstream oil and gas model: E&P

Assumptions, rows 41–47: PUD locations booked, FY0, Locations added to PUD, Probable reserves, FY0, Discoveries added to probable reserves…
Reserves, rows 6–11: Price revisions, selected deck, Opening PD reserves, Less: production, Revisions…
Reserves, rows 14–24: Opening PUD locations, Less: drilled, Added by extensions, Closing PUD locations…
Reserves, rows 27–33: Opening 1P reserves, Less: production, Revisions, Extensions and discoveries…
Reserves, rows 36–41: Opening probable reserves, Discoveries, Less: upgraded to proved, Closing probable reserves…
Reserves, rows 44–47: Reserve life, 1P (R/P), Reserve life, PD, Reserve life, 2P, Reserve replacement ratio, 1P

Inspect it in the browser Worked model Starter that leaves this schedule blank

What a reviewer looks for

Conversions from PUD to PD counted as additions to 1P.
PUD reserves that no longer equal the locations left times the EUR.
A reserve life on 2P compared with a peer’s on 1P.

Learn it, then build it

Read · Guide · 7 min

Equity Research Interview Questions: The Coverage Mindset

Vocabulary: Proved Reserves (1P and 2P).

Other operating schedules

Working capital schedule Capex and depreciation (PP&E roll-forward)Airline capacity and traffic: ASK, RPK and load factor Airline unit revenue and unit cost: RASK and CASK Airline fuel cost and hedging Type curves and production decline Realised prices and the field netback Units-of-production DD&A Container fleet: owned, chartered, newbuilds and scrapping Liftings and freight rate: a liner’s revenue Bunker fuel and the bunker adjustment factor Headcount pyramid: hiring, attrition and promotion Utilisation and realisation: hours to fee revenue Profit per partner: pay, bonus pools and partnership profit Store estate roll-forward and cohorts Retail sales: density, like-for-like and online Four-wall EBITDA and new-store payback Store leases under IFRS 16 Driver-based budget: volume, price, heads and cost per head Rolling forecast: actuals, reforecast and the outturn Price-volume-mix: revenue and margin variance Cost variances: rate, volume, heads and cost per head EBITDA bridge: plan to actual and forecast Capacity cohorts: MW, GPUs, utilisation and revenue Backlog roll-forward: contracts to revenue to cash Capital roll-forward Risk budget Trading cost base Sponsorship revenue