Changes

  | part    = Critical elements of the petroleum system

  | part    = Critical elements of the petroleum system

  | chapter = Evaluating source rocks

  | chapter = Evaluating source rocks

  | frompg  = 6-1

  | frompg  = 6-23

  | topg    = 6-41

  | topg    = 6-23

  | author  = Carol A. Law

  | author  = Carol A. Law

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch06/ch06.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch06/ch06.htm

  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

}}

}}

T_max is the temperature at which the maximum rate of hydrocarbon generation occurs in a kerogen sample during pyrolysis analysis. The S₂ peak represents the rate of hydrocarbon generation (the area under the curve represents the amount). The temperature at the time the S₂ peak is recorded during pyrolysis is T_max, given in °C. [[:file:evaluating-source-rocks_fig6-6.png|Figure 1]] shows output from a pyrolysis analysis and when Tmax is recorded.

T_max is the temperature at which the maximum rate of [[Petroleum generation|hydrocarbon generation]] occurs in a [[kerogen]] sample during [[Rock-Eval pyrolysis|pyrolysis]] analysis. The S₂ peak represents the rate of hydrocarbon generation (the area under the curve represents the amount). The temperature at the time the S₂ peak is recorded during pyrolysis is T_max, given in °C. [[:file:evaluating-source-rocks_fig6-6.png|Figure 1]] shows output from a pyrolysis analysis and when T_max is recorded.

[[file:evaluating-source-rocks_fig6-6.png|thumb|{{figure number|1}}See text for explanation.]]

[[file:evaluating-source-rocks_fig6-6.png|thumb|300px|{{figure number|1}}Output from a pyrolysis analysis and when T_max is recorded.]]

==Interpreting t_max==

==Interpreting T_max==

We can use the general guidelines for maturation levels given below for Rock-Eval pyrolysis Tmax for types II and III kerogens. Different pyrolysis techniques have different cutoffs for pyrolysis oil and gas generation zone boundaries. Pyrolysis Tmax can be significantly different for type I kerogen<ref name=ch06r13>Tissot, B., P., Pelet, R., Ungerer, P., 1987, [http://archives.datapages.com/data/bulletns/1986-87/data/pg/0071/0012/1400/1445.htm Thermal history of sedimentary basins, maturation indices, and kinetics of oil and gas generation]: AAPG Bulletin, vol. 71, p. 1445–1466. Excellent review of the relationships between maturation indicators and hydrocarbon generation from kerogens.</ref> or kerogen containing high sulfur concentration and is not a reliable indicator of maturity for these kerogen types.

We can use the general guidelines for maturation levels given below for [[Rock-Eval pyrolysis]] T_max for [[Kerogen types|types II and III kerogens]]. Different pyrolysis techniques have different cutoffs for pyrolysis oil and gas generation zone boundaries. Pyrolysis T_max can be significantly different for type I kerogen<ref name=ch06r13>Tissot, B., P., Pelet, R., Ungerer, P., 1987, [http://archives.datapages.com/data/bulletns/1986-87/data/pg/0071/0012/1400/1445.htm Thermal history of sedimentary basins, maturation indices, and kinetics of oil and gas generation]: AAPG Bulletin, vol. 71, p. 1445–1466. Excellent review of the relationships between maturation indicators and hydrocarbon generation from kerogens.</ref> or kerogen containing high sulfur concentration and is not a reliable indicator of maturity for these kerogen types.

{| class = "wikitable"

{| class = "wikitable"

|-

|-

! Hydrocarbon generation zone

! Hydrocarbon generation zone || Rock-eval pyrolysis T_max, °c

! Rock-eval pyrolysis tmax, °c

|-

|-

| Immature

| Immature || < 435

|

 

|-

|-

| Oil (from type II kerogen)

| Oil (from type II kerogen) || 435–455

| 435–455

|-

|-

| Oil (from type III kerogen)

| Oil (from type III kerogen) || 435–465

| 435–465

|-

|-

| Gas (from type II kerogen)

| Gas (from type II kerogen) || > 455

| >455

|-

|-

| Gas (from type III kerogen)

| Gas (from type III kerogen) || > 465

| >465

|}

|}

[[Category:Critical elements of the petroleum system]]  

[[Category:Critical elements of the petroleum system]]  

[[Category:Evaluating source rocks]]

[[Category:Evaluating source rocks]]