Recorded maximum bottom-hole temperatures may vary significantly from true formation temperatures. Circulation time and time since circulation are important variables in estimation of equilibrium bottom-hole temperatures. A theoretical temperature correction technique incorporating these factors was applied to well log-heading data to compute 191 static temperatures for 64 wells in the Scotian Shelf. A linear regression, performed on 140 computed temperatures produced an average geothermal gradient of 2.66°C/100 m; correlation coefficient 0.97. A geothermal gradient map constructed from the corrected data shows that areas of thicker sediment accumulation are marked by thermal highs (e.g., Abenaki, Sable subbasins), whereas areas of shallow basement coincide with ther al lows (e.g., LeHave Platform, Canso Ridge).

A technique for calculating maturation level of organic matter based on Lopatin's method and corrected bottom-hole temperatures was developed for the Scotian Shelf. A geologic model is constructed by superimposing a temperature grid on burial history curves. From this, TTI (Time-Temperature Index) values are derived which give the maturity level for specific sedimentary horizons. A comparison of 47 calculated TTI values with vitrinite reflectance measurements for 13 wells established a calibration of this technique for the Scotian Shelf. A correlation coefficient of 0.96 was obtained for the relation, log TTI = 6.7367 log Ro + 2.7317. This particular calibration of TTI is probably valid only for the Scotian Shelf since tectonic age and history play a role in the calibration. The proce ure of calculating TTI values is readily adaptable to a computer since a standard approach is followed for every well.

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