中国海相含油气盆地构造-岩相古地理特征

The characteristics of tectonic-lithofacies paleogeography of marine petroliferous basins of China

构造-岩相古地理是生-储-盖及成藏组合评价的基础,在油气勘探研究中占有十分重要的地位,然而,限于资料和认识程度,我国主要海相含油气盆地已有的相图难以满足深层海相碳酸盐岩快速勘探的需求。应用新的钻井和地震资料,结合岩相识别技术,开展了塔里木盆地、四川盆地和鄂尔多斯盆地海相碳酸盐岩构造-岩相古地理研究,取得以下成果认识:①我国小克拉通海相碳酸盐台地构造-古地理具有隆坳相间、隆控储、坳控源的特点;②构造-岩相古地理具有"多台缘、多滩带和多台盆"的特点;③构造-岩相古地理对早期白云石化的发生和岩溶作用的范围及改造程度具有重要影响,从而控制储层分布;④建立了"多台缘"镶边台地模式并改进"双滩"缓坡沉积模式,揭示我国海相碳酸盐台地内部具备多种有利成藏组合。研究成果深化了我国小克拉通碳酸盐台地构造-岩相古地理共性特点的认识,为深层海相碳酸盐岩油气勘探提供了理论支撑。

Tectonic-lithofacies paleogeography is the foundation of the evaluation for source–reservoir-cap and reservoir-forming assemblage,which plays a significant role in oil and gas exploration.However,because of the limited data and recognition,the existing facies maps of major marine basins in China can not meet the needs of oil and gas exploration in deep marine carbonate rocks.Based on the new drilling and seismic data,the lithofacies recognition technology was used to restore the marine tectonic-lithofacies paleogeography of Tarim Basin,Sichuan Basin and Ordos Basin.It is concluded that:(1)the tectonic paleogeography of China’s marine carbonate platform in small craton is characterized with the alternation of uplift and depression,and uplift controlling reservoir and depression controlling source rocks;(2)tectonic-lithofacies paleogeography is characterized with multiple platform margins,multiple shoal zones and multiple platform basins;(3)tectonic-lithofacies paleogeography plays an important role in the early dolomitization and the range and reconstruction degree of karstification,thus controlling the distribution of reservoir;(4)multiple margin platform model is established and double-shoal sedimentary model of gentle slope is improved,which reveals that there are many favorable reservoir-forming assemblages in the marine carbonate platform of China.The research results deepen the understanding of the common characteristics of China’s marine carbonate platform in small craton,and provide theoretical support for oil and gas exploration of deep marine carbonate rocks.