Deep Underground Science and Engineering

10 000-m deep, Chinese craton basin, dolomite genesis, oil and gas exploration potential, reservoir distribution,reservoir preservation

The 10000-m ultradeep dolomite reservoir holds significant potential as a successorfeld for future oil and gas exploration in China's marine craton basin. However, majorchallenges such as the genesis of dolomite, the formation time of high-qualityreservoirs, and the preservation mechanism of reservoirs have always limitedexploration decision-making. This research systematically elaborates on the genesisand reservoir-forming mechanisms of Sinian-Cambrian dolomite, discussing theancient marine environment where microorganisms and dolomite develop, whichco腖前官t洤頣参仏嘗鍚茫仏鈡s th鵇訉蒄蜇籂千摇即镌格rmation of large-scale Precambrian Cambrian dolomite. The periodicchanges in Mg isotopes and sedimentary cycles show that the thick-layered dolomite isthe result of different dolomitization processes superimposed on a spatiotemporalscale. Lattice defects and dolomite embryos can promote dolomitization. By simulatingthe dissolution of typical calcite and dolomite crystal faces in different solution systemsand calculating their molecular weights, the essence of heterogeneous dissolution andpo羴淅昵的想碚骓銘駒墥笹赂樅方巾rm錚撬鑽各敫驏范猼磡鈧容 on typical calcite and dolomite crystal faces was revealed, and themechanism of dolomitization was also demonstrated. The properties of calcite anddolomite (104)/(110) grain boundaries and their dissolution mechanism in carbonatesolution were revealed, showing the limiting factors of the dolomitization process andthe preservation mechanism of deep buried dolomite reservoirs. The in situ laser U-Pbisotope dating technique has demonstrated the timing of dolomitization and poreformation in ancient carbonate rocks. This research also proposed that dolomitizationoccurred during the quasi-contemporaneous or shallow-burial periods within 50 Maafter deposition and pores formed during the quasi-contemporaneous to the earlydiagenetic periods. And it was clear that the quasi-contemporaneous dolomitizationwas the key period for reservoir formation. The systematic characterization of thespatial distribution of the deepest dolomite reservoirs in multiple sets of the Sinian andthe Cambrian in the Chinese craton basins provides an important basis for thedistribution prediction of large-scale dolomite reservoirs. It clarifies the targets for oiland gas exploration at depths over 10 000 m. The research on dolomite in this studywill greatly promote China's ultradeep oil and gas exploration and lead the Chinesepetroleum industry into a new era of 10 000-m deep oil exploration.

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354-381

2770-1328

SCI