In the heart of China’s marine craton basins, a new frontier in oil and gas exploration is emerging, one that delves into the mysteries of ultradeep dolomite reservoirs. A groundbreaking study led by Guangyou Zhu from the School of Geosciences at Yangtze University in Wuhan, China, is shedding light on the genesis and preservation of these 10,000-meter-deep dolomite reservoirs, potentially unlocking vast energy resources.
The study, published in the journal *Deep Underground Science and Engineering* (translated from Chinese as *Deep Underground Science and Engineering*), systematically explores the formation and preservation mechanisms of Sinian–Cambrian dolomite reservoirs. These reservoirs hold significant promise for future oil and gas exploration in China, but their potential has remained largely untapped due to the complexities surrounding their genesis and preservation.
Zhu and his team have uncovered crucial insights into the ancient marine environments where microorganisms and dolomite coexisted, controlling the formation of large-scale Precambrian–Cambrian dolomite. “The periodic changes in Mg isotopes and sedimentary cycles reveal that the thick-layered dolomite is the result of different dolomitization processes superimposed on a spatiotemporal scale,” Zhu explains. This understanding is pivotal for predicting the distribution of these reservoirs and guiding exploration efforts.
The research also delves into the molecular mechanics of dolomitization, simulating the dissolution of typical calcite and dolomite crystal faces in different solution systems. This work has revealed the essence of heterogeneous dissolution and pore formation, providing a deeper understanding of the dolomitization process and the preservation mechanisms of deep buried dolomite reservoirs.
One of the most significant findings is the timing of dolomitization and pore formation. Using the in situ laser U–Pb isotope dating technique, the team demonstrated that dolomitization occurred during the quasi-contemporaneous or shallow-burial periods within 50 million years after deposition, with pores forming during the quasi-contemporaneous to early diagenetic periods. “Quasi-contemporaneous dolomitization was the key period for reservoir formation,” Zhu emphasizes, highlighting the critical window for the development of these high-quality reservoirs.
The implications for the energy sector are profound. The systematic characterization of the spatial distribution of the deepest dolomite reservoirs in multiple sets of the Sinian and Cambrian in the Chinese craton basins provides an important basis for predicting the distribution of large-scale dolomite reservoirs. This research clarifies the targets for oil and gas exploration at depths over 10,000 meters, potentially opening up a new era of ultradeep oil exploration.
As China and the world seek to secure energy resources for the future, this research offers a roadmap for exploring the vast potential of ultradeep dolomite reservoirs. By understanding the genesis and preservation mechanisms of these reservoirs, the energy sector can make more informed exploration decisions, ultimately leading to the discovery of new oil and gas fields. The study not only advances our scientific understanding but also paves the way for technological innovations in deep exploration techniques.
In the words of Zhu, “This research will greatly promote China’s ultradeep oil and gas exploration and lead the Chinese petroleum industry into a new era of 10,000-meter-deep oil exploration.” As the energy sector continues to evolve, the insights gained from this study will be instrumental in shaping the future of oil and gas exploration, ensuring a sustainable energy supply for generations to come.