2019 was a year of high accomplishment for EGI Petroleum Geochemistry Lab Manager Dhrupad Beti, who not only successfully passed the oral defense of his PhD thesis in early November, but was also honored by the Houston Geological Society & EAGE Conference on Latin America for his poster presentation at the November conference.
The poster, “Application of a new resource assessment workflow to offshore Suriname: Correction for mineral matrix effect and reclassification of organofacies,” was awarded second runner up in the student poster presentation category.
To view the winning poster, click on the image below to expand.
Dr. Beti’s oral thesis defense, titled “Experimental Determination of Quantity and Quality of Hydrocarbons in Sedimentary Rock Samples,” was presented in early November 2019 to members of his committee (Dr. Terry Ring, Dr. Lauren Birgenheier, Dr. John McLennan, Dr. Milind Deo, Dr. Raymond Levey), EGI staff and visiting scholars, and colleagues in the Department of Chemical Engineering.
Dhrupad started at EGI as a student while pursuing first his Master in Petroleum Engineering and then a PhD in Chemical Engineering at the University of Utah. EGI extends our warmest congratulations to Mr. Beti for his accomplishments and we look forward to sharing in his bright future.
Experimental Determination of Quantity and Quality of Hydrocarbons in Sedimentary Rock Samples
The objective of this study is to understand the quantity and quality of hydrocarbons present in sedimentary rock samples using existing experimental tools. The motivation for this was mainly driven by the unconventional oil and gas revolution, where the source and reservoir rock are the same. Pyrolysis techniques historically investigated source of hydrocarbons in conventional reservoirs, where source and reservoir rocks are different. Analyzing these unconventional rock samples for the quality and quantity of hydrocarbons is the subject of this thesis and is a necessary step to gather better understanding of the fluids present in-situ.
In an attempt to gather more information from the S1 peak, a new method that divides S1 peak (thermally vaporized hydrocarbon up to 300°C) into six different peaks, called “Incremental S1” is presented. Experiments using the Incremental S1 method were performed on engineered samples where crude oil of different API gravity is artificially introduced into sandstone. Experiments using real geologic samples representing the three-rock types are also analyzed using the Incremental S1 method. A new data processing procedure to extrapolate the experimental signal to attain an accurate area under the curve is presented. To validate the boiling point distributions attained from the Incremental S1 experiments, six-stage, two-phase flash separation simulations of crude oil composition sourced from locations all over the world (192 locations) are performed. Thermal-desorption experiments are also performed to confirm the Incremental S1 results. A detailed review of other pyrolysis methods used to understand the quality and quantity of hydrocarbons, along with their respective advantages and limitations are presented. Knowing the implications of evaporation losses in the determination of the quantity and quality of hydrocarbons, a thermodynamic model is developed to simulate evaporation losses in rock samples. Lastly, in order to study the influence of mineral matrix effect on the quality and quantity of the precursor of hydrocarbon (kerogen), and its effect in estimating the key exploration parameters such as SPI (Source Potential Index) and GOR (Gas Oil Ratio), multiple kinetic simulations were performed.
The results presented in this study show that the new Incremental S1 method not only provides qualitative information of hydrocarbons present in rock samples, it also enables accurate estimation of the quantity of hydrocarbons present in rock samples. It is concluded that an estimation of evaporation losses can be performed if the initial moles of hydrocarbons is assumed. It is also concluded that the mineral matrix effect in the pyrolysis of Kerogen can be corrected using palynofacies analysis and improved methods to calculate SPI and GOR (developed here) are employed.