Abstract The distribution and abundance of pyrrolic compoundsin sediments and crude oils are most likely influencedby inorganic sedimentary components. In thispaper, thermal simulation experiments on the systempyrrole-hematite-water were carried out at elevated temperaturesand pressures in order to investigate the effectof organic-inorganic interactions on the preservationof pyrrolic compounds. Compositions of the reactionproducts were analyzed with GC-MS and GC-FIDmethods. In the closed system pyrrole-hematite-water, thenitrogen-oxygen exchange obviously occurred at temperaturesabove 350ºC in accordance with the thermochemicalcalculation. Large amounts of furan and ammonia weregenerated after simulation experiments, indicating thatthe conversion of pyrrole into furan was the dominant reaction.Thermochemical exchange effect between organicnitrogen and inorganic oxygen was obviously facilitatedby elevated temperatures and found to be catalyzed byhematite, but inhibited by the increasing volume of water.Thermodynamically water spontaneously reacts with pyrroleabove 300ºC. The reaction of pyrrole-hematite-wateris an exothermic process in which the reaction heat positivelycorrelates with temperature. The heat released wasestimated as 9.0 KJ/(mol) pyrrole - 15.0 KJ/(mol) pyrrole intypical oil reservoirs (100ºC–150ºC) and 15.0–23.0 KJ/(mol)pyrrole in typical gas reservoirs (150ºC–200ºC). The calculatedactivation energy of the nitrogen-oxygen atom exchangeis about 129.59 kJ/mol. According to the experimentalresults, a small amount of water may effectivelyinitiate the nitrogen-oxygen exchange. The study wouldimprove our evaluating of the preservation and fate ofpyrrolic compounds in deeply buried geologic settings andfurther understanding of thermochemical processes behindthe degradation of petroleum.