Rock-Eval analysis and organic petrographical characterization of the Upper Jurassic Naokelekan Formation, northern Mesopotamian basin, Kurdistan Region-Iraq

The aim of this study is to assess the type, thermal maturity and the petroleum generation potential of the Upper Jurassic Naokelekan Formation, occurring across the Kurdistan Region of Iraq, by applying organic petrographical methods and Rock-Eval analysis. The Rock-Eval data would indicate the presence of kerogen types III, IV and II as the main constituents. However, the qualitative petrographical evaluation revealed that the main organic constituents are solid hydrocarbons, in the form of microgranular migrabitumens, with minor amounts of pyrobitumens. These secondary particles have affected the results of the Rock-Eval analysis and would have led to misinterpretation of organic matter typification based on pyrolysis results only. The combined results of petrography and pyrolysis indicate an active petroleum system within the Upper Jurassic sequence, where hydrocarbons are generated and reservoired within suitable lithologies.

PARAMETERS CRYSTALLIZATION PROCESSES AND SOLID PETROLEUM HYDROCARBONS DISSOLUTION

In the proposed work, the experimental data on the processes of crystallization and different nature waxy hydrocarbons recrystallization in hydrocarbon solvents have been compared. T-1 technical paraffin (GOST 23683-89) with the melting point of 54 °С and ceresin-80 (GOST 2488-79) with the dropping temperature of 80 °C have been used. РТ-1 kerosene (GOST 10227-86) and de-waxed oil of fraction 420-490 °С have been used as hydrocarbon solvents. The experimental data on crystallization and recrystallization processes of paraffin wax with a melting temperature of 54 ºC and ceresin with a dropping temperature of 80 °C in kerosene and dewaxed oil are presented in this paper. It is shown that chemical structure has the main influence on the processes of crystallization and recrystallization of solid petroleum hydrocarbons. An exceedance of solid hydrocarbons solution temperatures tр above their cloud points tп has been observed which is explained by hysteretic processes. The temperature difference Δt = tр- tп depends on the solid hydrocarbons nature and their content in solvents. Wax solutions in kerosene have higher values Δt relative to ceresin solutions in kerosene, which can be explained by the difference in chemical structure of solid hydrocarbons. With the increase in solid hydrocarbons content in their solvents due to the differences in solid hydrocarbons diffusion rate, Δt decreases. The discovered regularities of solid hydrocarbons crystallization and recrystallization should be taken into account in the processes of paraffin oil production, transportation and processing.

Gilsonite exploration by using electrical resistivity tomography with multi-electrode gradient array: Acase study in Rionegro (Colombia)

Subsurface exploration using geophysical methods has increased the prospective economic possibilities for new non-metallic minerals and other raw materials such as solid hydrocarbons. In this paper, we show results of electrical resistivity tomography (ERT) carried out by using the multi-electrode gradient array, and conducted with the main purpose ofmapping thehighresistivity anomalies relatedto the presence of solid hydrocarbons bodies. ERT profiles were interpreted trough considering the gilsonite evidence on rocky outcrops in the La Luna Formation (Ksl) and their respective lithological contact with the Bocas Formation (Jb). This study concludes that,both on thesurface and in the subsurface, in the stratification plane of La Luna Formation, the gilsonite is a tabular and oblique shape, and the contact Ksl-Jb is faulty with an almost vertical inclination.However,different structural processes have contributed to theirregularformation and massive body of gilsonite. Finally,the study concludes that resistivity tomographies represent a reliable alternative for preliminary exploration stages. Sincethe cost of the methodisrelatively low in Colombia, it also serves as aneconomically viable alternative for small exploratory projects.

Independent gilsonite vein, Uintah County

The Uinta Basin of northeastern Utah contains a wide variety of hydrocarbon resources including vast accumulations of crude oil and natural gas deposits, one of the largest oil shale resources in the world, and the largest tar sand deposit in the United States. In addition, unique solid hydrocarbons, including gilsonite, wurtzilite, tabbyite, and ozokerite, have a long and colorful history of exploration and/or production in the region. The most abundant of these, gilsonite, occurs in distinctive swarms of subparallel, northwest-trending veins. The lateral continuity of the veins is impressive, with relatively long, straight ribbons stretching across the hills of the eastern Uinta Basin. The veins are also vertically continuous, extending hundreds to more than 3000 feet (900 m) below the ground, commonly having only small variations in width. The Uinta Basin contains the world’s largest deposit of gilsonite and is the only place in the world where this unique resource is economically produced. Gilsonite is remarkable for its unusual geologic origin, chemical and physical properties, and industrial uses. Industry pioneers are noted for creating innovative uses for their product and for over 100 years have solved mining, processing, transportation, marketing, and other challenges to supply gilsonite to world markets. Accordingly, gilsonite has been studied and described in a large body of research dating back to the 1880s. Most recently, the Utah Geological Survey (UGS) published Special Study 141 (Boden and Tripp, 2012), which presents the latest mapping of gilsonite deposits and a compilation of existing data. To date, over 70 significant veins and vein systems, having a total combined vein length of over 170 miles (270 km), have been mapped by UGS geologists.