Geophysics
Thermal Maturity & Geothermal Lab
Gradient, heat and the oil window in one well model.
Computes the geothermal gradient from formation and surface temperatures, and places samples in the oil or gas window using vitrinite reflectance and Rock-Eval Tmax.
Overview
Each well or sample becomes a row in the thermal maturity record and a point on the temperature–depth chart. Academic guidelines beside the form explain each threshold.
What you enter · What you get
What you enter
- Well name or sample ID
- Formation depth (m)
- Formation and surface temperature (°C)
- Vitrinite reflectance Ro (%) and Tmax (°C)
What you get
- Geothermal gradient (°C/km)
- Maturity stage: immature, oil, gas
- Temperature–depth chart
- Excel export
How it works in the field
Enter well data
Analyse and plot
Export the record
Method and equations
Geothermal gradient and heat flow
Linear gradient between surface and formation temperature; heat flow with an assumed thermal conductivity.
G = 1000 (Tf − Ts) / z · q = k · G
Maturity windows
Oil window Ro 0.6–1.1 % or Tmax 430–465 °C; wet gas to 1.35 %; dry gas beyond (Peters & Cassa 1994).
Who uses it
Basin modellersGeothermal-energy researchersWell-site geologists
Standards and references
- Peters, K.E. (1986). Guidelines for evaluating petroleum source rock using programmed pyrolysis. AAPG Bulletin, 70(3), 318–329.
- Dow, W.G. (1977). Kerogen studies and geological interpretations. Journal of Geochemical Exploration, 7, 79–99.
- Beardsmore, G.R. & Cull, J.P. (2001). Crustal Heat Flow: A Guide to Measurement and Modelling. Cambridge University Press.
Results support professional judgement. They do not replace a licensed engineer’s or geologist’s sign-off.
At a glance
- Category
- Geophysics
- Runs on
- Phone, tablet and desktop browser
- Export
- CSV table, PNG chart, PDF report
- Access
- Subscribers
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