再论中国陆上深层海相碳酸盐岩油气地质特征与勘探前景

深层碳酸盐岩是我国陆上油气勘探发展的重要接替领域,加强对深层碳酸盐岩的油气地质研究与探索,对于实现我国油气工业持续、稳定、健康发展具有十分重要的现实意义。通过对深层碳酸盐岩基本地质条件的深入分析,发现中国陆上深层碳酸盐岩资源潜力可能超过预期,具备发现大油气田的良好前景。具体表现在4个方面:①发育常规烃源岩和源岩内滞留液态烃裂解两类烃源灶,都可以规模供烃;②受顺层、层间两类岩溶作用和埋藏、热液两类白云石化作用的控制,深—超深层碳酸盐岩仍可以发育规模有效储层;③在递进埋藏和退火受热耦合作用下,部分海相烃源岩可以跨构造期成藏,晚期仍有大量液态烃生成,深层碳酸盐岩油、气均富;④多期构造运动作用形成的大型隆起背景、3种类型成藏模式(隆起斜坡区岩溶储层似层状大面积成藏、古潜山风化壳岩溶储层倒灌式大面积成藏、礁滩储层大范围成藏),以及古隆起围斜区及台缘带广泛发育的地层、岩性圈闭群呈集群式大面积分布。结论认为:中国陆上深层碳酸盐岩具备大面积、规模成藏的有利条件,可以形成大油气田。

Petroleum geological features and exploration prospect in deep marine carbonate strata onshore China: A further discussion

Deep marine facies carbonate reservoirs have become one of the important succession regions of China onshore oil and gas exploration and development, so such exploration and geological research in this field is of realistic significance to the sustainable, steady and smooth development in oil and gas sector in China. Therefore, through a deep investigation into the fundamental geological conditions of deep marine carbonate reservoirs, we found that such resource potential is great and far beyond the expectation, so there is a great prospect for such great discoveries as giant oil or gas fields. The following findings were obtained. First, there are two kinds of hydrocarbon kitchens, which were respectively formed by conventional source rocks and liquid hydrocarbons cracking that were detained in source rocks, and both of them could provide large scale hydrocarbons. Second, the petrophysical properties of carbonate reservoirs are immune from their buried depth due to the bedding and interstratal karst, as well as the burial and hydrothermal dolomitization, so effective carbonate reservoirs could be extensively developed in the deep and ultra deep strata. Third, parts of marine source rocks could form hydrocarbon accumulations spanning important tectonic phases under the coupling effects of progressive burial and annealing geothermal field, and liquid hydrocarbons could be kept in ultra deep strata over 7000 meters meaning that not only gas pools but also oil pools could be found in deep marine strata. Fourth, large scale uplifts were formed by the stacking of multi episodic tectonism and oil and gas could be accumulated through three types, i.e., downward invasion model, lift model and switching model. In addition, groups of stratigraphic and lithologic traps were widely developed in the areas of percline structure of paleouplifts and continental margins. In conclusion, large scale fields could be formed in marine carbonate strata in onshore basins of China because of the above mentioned advantages.