Evaluating the total oil yield using a single routine Rock-Eval experiment on as-received shales

In this study, a fast method for evaluating the total oil yield using a single routine Rock-Eval experiment on as-received shales is proposed. First, the temperature threshold (TOK) of the S2oil and cracking hydrocarbons were determined by combining the pyrograms of the as-received shale with a solvent-extracted replicate. Then, the total oil yield was directly derived from the hydrocarbons evaporate at a temperature below than TOK in a routine Rock-Eval experiment. The results show that the TOK value is controlled by the sample’s maturity and pore structure. The higher the maturity, the larger the specific surface area and the smaller the pore size, the greater the TOK. A prediction model of TOK was proposed based on the sample’s production index (PI). The total oil yields estimated by the two methods of both the TOK prediction model and the average TOK value (465 °C) are consistent with those obtained by Jarvie (2012) using the thermal-extraction method with correlation coefficients of 0.983 and 0.9548, respectively. Compared with the previous methods, the single routine Rock-Eval experiment method proposed in this study is convenient and not requires an extraction experiment. In addition, there are archived routine pyrolysis data available that can be used to directly calculate the total oil yield based on the temperature threshold.

Source: Journal of Analytical and Applied Pyrolysis - October 14, 2019 Category: Chemistry Source Type: research