Recent research into the Ordovician Majiagou Formation in the east-central Ordos Basin has unveiled crucial insights into its thermal history and hydrocarbon accumulation stages, which could significantly impact the region’s energy sector. Led by Hua Tao from the Department of Geology at Northwest University in Xi’an, this study, published in the journal Energies, highlights the exploration potential of marine carbonates in this area, which has already garnered attention due to past successful gas flows.
The study indicates that the thermal evolution of the carbonate reservoirs is mainly influenced by the basin’s deep thermal structure, showing a notable trend of decreasing thermal values from south to north. The Fuxian area stands out as a hotspot, situated at the center of Early Cretaceous thermal anomalies, with organic matter maturity levels reaching up to 3.2%. This information is critical for energy companies looking to assess the viability of hydrocarbon extraction in the region.
Thermal history is essential for understanding when hydrocarbons are generated and accumulated. The research identified three significant thermal evolution stages: a slow warming phase before the Late Permian, a rapid warming phase from the Late Permian to the Early Cretaceous, and a subsequent cooling stage. This evolution is linked to significant geological events that have shaped the basin’s current hydrocarbon landscape. “The present geothermal gradient of the Ordovician Formation exhibits characteristics of east-high and west-low, with an average of 28.6 °C/km,” Tao noted, emphasizing the varying potential across the basin.
Fluid inclusions within the carbonate rock strata provide further insights into hydrocarbon charging periods, with temperatures recorded between 110–130 °C for early-stage inclusions and 160–170 °C for late-stage inclusions. These temperatures correlate with two distinct hydrocarbon charging periods, occurring during rapid warming phases that could represent optimal times for exploration and extraction activities.
For energy companies and investors, understanding these thermal histories and hydrocarbon accumulation stages opens up new avenues for exploration. The estimated proven reserves in the Ordovician formation are substantial, approximately 2384.85 × 10^8 m³, indicating a strong potential for future development. The findings of this study not only enhance the geological understanding of the region but also provide a solid foundation for strategic investment in hydrocarbon exploration.
As the global energy landscape continues to evolve, the insights provided by Hua Tao and his team will be invaluable for guiding future exploration efforts in the Ordovician carbonate reservoirs of the Ordos Basin. The research underscores the importance of thermal history in hydrocarbon generation and accumulation, reinforcing the potential of this region as a key player in the energy market.
