Devonian shale, thermal

A Comparison Between the Properties of Devonian Shale and Green River Oil Shale via Thermal Analysis... 

Figure 1. TGA and DTG thermal analyses for (A) Green River shale kerogen and (B) Devonian shale kerogen (No. 43)...

Table II. Activation Energy for Thermal Decomposition of Raw Shale and Kerogen Concentrate from Green River Oil Shale and Devonian Shale °...

Figure 2. DSC thermal analysis for (A) Green River oil shale and (B) Devonian shale (No. 43). (Both raw shale and kerogen concentrate.) (--) Raw shale, (----) kerogen concentrate, (— —) baseline.

The thermal properties of Devonian shale are quite different from those of Green River oil shale. The associated pyrite in kerogen concentrate may contribute greatly to the effect on thermal degradation of Devonian gas-bearing shale. For the first time DSC was applied to determining thermal properties of Devonian shale as well as Green River oil shale. 

Figure 3. DSC thermal analysis of pyrite in (A) pyrite mineral (Rico, Colorado), (B) Devonian shale kerogen, and (C) pyrite-reduced kerogen of...

The Kettle Point Formation subcrops in southwestern Ontario. It is up to 60 m thick, with organic carbon values usually in the range 5%-16% and Fischer Assay oil yields up to 70 1/t (17 gal/ton). The organic matter is dominantly kerogen of marine origin and has attained only an immature thermal maturation stage. A particularly rich upper zone is present over much of the subcrop area and its thickness seems to be controlled by post-Kettle Point erosion. Although studies are still preliminary, especially for the Devonian shales, the Kettle Point Formation appears to have the most potential for shale oil production in southern Ontario. 

The C4-naphthalene and C4-benzene data presented in this paper were collected as part of a larger study addressing the influence of pressure, temperature and time on hydrocarbon generation (Hill et al, 1994, 1996, 2(X)3). The goal of the study was to evaluate whether maturity parameters defined during oil pyrolysis could be extended to natural systems. Thus, the Devonian sourced oil from the WSCB was used to define C4-naphthalene and C4-benzene maturity parameters in the oil pyrolysis experiments and Mississippian oils from the Fort Worth Basin were used to evaluate C4-naphthalene and C4-benzene maturity parameters in natural systems. It was not the goal of this study to determine whether results from pyrolysis of a Devonian oil will compare exactly with oils from a Mississippian source. Due to facies differences between Devonian and Mississippian marine shales, the initial distribution of C4-naphthalene and C4-benzene isomers is different as discussed earlier. For this reason, we would also not expect maturity ratios from pyrolysis of a Devonian oil to exactly match maturity ratios from Mississippian Barnett Shale oils. However, if the maturity trends observed from oil pyrolysis results are valid, the C4-naphthalene and C4-benzene ratios should correlate with a well established thermal maturity parameter such as TAS in Mississippian Barnett Shale oils. 

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