Geochemical Characteristic of Some Oil Shale Deposits of Israel

Abstract

This preliminary study investigates the organic petrology and geochemistry of several notable Late Cretaceous organic-rich carbonate oil shale deposits associated with the upwelling belt in the SE of of Tethyian Margin, central Israel and compared with other world prominent oil shale examples (e.g., US, Canada, and Mongolia). The results of this study show that the oil shale deposits of Israel contain highly labile organic matter such as chlorophyll and lipid–derived matter, which normally degrade during early diagenesis, indicating that these oil shales did not undergo thermal stress required for generation of hydrocarbons. These oil shales were also deposited in an environment with a powerful combination of extreme organic matter production and excellent preservation which has secured rapid accumulations of these organic-rich deposits. Elemental signatures are suggestive of a warm, shallow marine environment as indicated by low boron content (<50 ppm). High nutrient content and as shown by extreme enrichment of phosphorus has promoted high levels of organic matter production. This, along with anoxic condition resulted in preservation of labile organic matter. Prevailing anoxic to euxinic conditions is supported by elevation of redox-sensitive trace elements including molybdenum and uranium. The combined effects of high accumulation of organic matter and excellent preservation has resulted in a significantly higher proportion of labile organic matter in these oil shale deposits compared to similar deposits in other areas of the world. These attributes provide favorable conditions for higher extraction of hydrocarbons utilizing lower energy consumption during thermal cracking processes.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016