The Qaidam Basin, recognized as one of the major petroliferous areas in western China, is gaining attention for its hydrocarbon resource potential. Recent research has analyzed 113 source rock samples from the Upper part of the Lower Ganchaigou Formation (E32) to assess their hydrocarbon generation potential and geochemical characteristics. The study, published on March 10, 2025, leverages advanced techniques including Rock-Eval 6 pyrolysis, gas chromatography-mass spectrometry (GC-MS), and cluster analysis to draw important conclusions about these source rocks.
This research is particularly significant as the world faces increasing energy demands alongside the gradual depletion of conventional hydrocarbon reserves. Evaluations of source rocks are key to ensuring energy security and driving future exploration efforts. Source rocks serve as the organic material for hydrocarbon generation, and their assessment requires detailed geochemical analysis, including organic matter origin, deposition environments, and conversion processes.
Through the study, the authors discovered notable insights about the E32 source rock, which was found to exhibit fair hydrocarbon generation potential. The source rock is predominantly composed of Type I and Type II1 kerogens, which play diverse roles depending on their organic composition derived from both aquatic organisms and higher plants, with aquatic organisms contributing more significantly. The total organic carbon (TOC) content across the samples varied from 0.23% to 2.86%, with the average value resting at 0.77%. Notably, 53.6% of the identified samples exhibited TOC content ranging from 0.4% to 0.8%, which is considered optimal for hydrocarbon production.
The hydrocarbon group composition revealed average markers indicating 49.35% for saturated hydrocarbons, 22.07% for aromatic hydrocarbons, 18.07% for resins, and 10.51% for asphaltenes. The study measures key parameters like hydrocarbon generation potential (Pg), which ranged from 0.004 mg/g to 17.86 mg/g, averaging at 2.28 mg/g, and indicates various thermal maturity stages observed through vitrinite reflectance (Ro) values, ranging from 0.45% to 0.91%. These findings indicate the source rock is currently classified as being within low-maturity to mature stages.
Employing cluster analysis allowed researchers to treat geochemical data statistically, achieving valuable insights about the formation history and migration pathways of hydrocarbons from these rocks. Through unsupervised learning techniques, they addressed the variances and relationships among different samples, providing answers to the complex questions of how mixed-source oils correlate with their originating rock structures.
The significance of this study extends beyond just the Qaidam Basin, giving researchers worldwide effective methodologies to evaluate source rock characteristics for regions with similar geological formations. Understanding oil-source relationships and hydrocarbon migration dynamics is instrumental for future explorations, especially considering the ever-evolving demands of the global energy market.
Overall, the research validates threshold TOC values and evaluates hydrocarbons within mixed-source crude oils, asserting the importance of refining existing analytical models. Insights garnered from this study promise to enrich the discourse on hydrocarbon exploration strategies wherein identifying the sources and migration pathways remains critically relevant for sustainable energy solutions.