| Author's Name: SHEN Anjiang, CHEN Ya’na, MENG Shaoxing, ZHENG Jianfeng, QIAO Zhanfeng,NI Xinfeng, ZHANG Jianyong, WU Xingning |
| Marine carbonate rocks in China are characterized by aging, developing in small-scale cratons and locating in the lower tectonic layer of superimposed basins. Reservoir genesis and distribution are among the many scientific problems in hydrocarbon exploration. This paper summarizes three innovative achievements made by the project team of the Key Laboratory of Carbonate Reservoir in the past five years in the field of marine carbonate sedimentary reservoir research in China as follows: (1)based on the analysis of tectonic-lithophase paleogeography of the Sinian-Cambrian, Changxing Formation-Feixianguan Formation in Sichuan Basin, it is found that the intra-platform rifts in small-scale craton were generally developed, and thus the carbonate platform sedimentary models of bi-margin ＆ bi-shoal were
established. This discovery reveals that the source rocks and large-scale reservoirs can also develop in the intra-platform,which provides a theoretical basis for the exploration field expansion from the margin to the internal of the platform, and it was confirmed by the discovery of the Anyue gas field; (2)based on the exploration practice of karst reservoirs in the Tarim Basin, innovations in the genesis of karst reservoirs and the type ＆ distribution of karst reservoirs of intracarbonate rocks broke the traditional view that the karst reservoirs mainly develope in the buried hills. This view extends the exploration realm from the buried hill areas to intra-carbonate rocks areas, and it was confirmed by the discovery of Harahatang and Shunbei oilfield on the south slope of North Tarim Basin; (3)the old and deep-buried marine carbonate reservoirs are still facie-controlled and the pores are more inherited from pre-buried stage than modificated in buried stage, which laid the foundation for the scale and predicatability for deep-buried and ancient marine carbonate reservoirs,which promote the exploration values of these reservoirs. This view was confirmed by the hydrocarbon exploration practice in Tarim and Sichuan Basins. Reef-shoal(mound) facies, evaporite tidal flats, sequence boundaries, exposure surfaces and unconformities, paleo-uplifts and fault systems control the distribution of high-quality and large-scale reservoirs of deep-buried and ancient marine carbonates. These understandings not only have important theoretical significance for the development of carbonate sedimentary reservoir discipline, but also provide basis for the expansion of exploration field. |
