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 T_max for 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.

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 T_max, °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]]