摘要
The Rock-Eval technique in the last few decades has found extensive application for source rock analysis.The impact of shale particle crush-size and sample weight on key Rock-Eval measurements,viz.the S;curve(heavier hydrocarbons released during the non-isothermal pyrolysis-stage)and the S;curve(CO_(2)released from oxidation of organic matter during the oxidation-stage)are investigated in this study.For high and low total organic carbon(TOC)samples of different thermal maturity levels,it is apparent that particle crush-size has a strong influence on the results obtained from RockEval analysis,with the effect being stronger in high-TOC samples.In comparison to the coarser-splits,S;and pyrolyzable carbon(PC)were found to be higher for the finer crush sizes in all the shales studied.The S_(2)CO_(2)oxidation curve shapes of Permian shales show contrasting signatures in comparison to the Paleocene-aged lignitic shale,both from Indian basins.A reduced TOC was observed with rising sample weight for a mature Permian shale from the Jharia basin,while the other shales sampled showed no significant reduction.The results indicate that the S_(2)CO_(2)curve and the S_(2)T_(2),are strongly dependent on the type of organic-matter present and its level of thermal maturity.Sample weight and particle size both influence the S;-curve shapes at different heating rates.With increasing sample weights,an increase in S;-curve magnitude was observed for the shales of diverse maturities.These differences in the S;curve shape lead to substantially different kinetic distributions being fitted to these curves.These findings are considered to have significant implications for the accuracy of reaction kinetics obtained from pyrolysis experiments using different sample characteristics.
基金
awarding BH the CSIR-CIMFR in-house research grant(No.MLP-93/2019-20),the funds of which were utilized to purchase the Rock-Eval 6 device at CSIR-CIMFR and conduct the research。
