中国西部叠合盆地深部油气勘探面临的重大挑战及其研究方法与意义

Key challenges and research methods of petroleum exploration in the deep of superimposed basins in western China

在综合调研和收集了世界深部油气藏大量资料及对中国西部叠合盆地油气地质特征深入研究的基础上,总结提出中国西部叠合盆地深部油气勘探面临着三方面的重大挑战:①油气组成复杂,多期混合、来源不清,致使深部油气勘探方向难以确定;②富集油气的有效储层裂缝和溶蚀孔洞混杂,成因机制不清,导致勘探区带预测困难;③油气相态变异大,油气分布特征受深部高温压环境、低孔渗介质条件和多种运聚动力的影响,使得现有的成藏理论难以有效指导勘探目标的预测。因此认为,加速中国西部叠合盆地深部油气勘探必须解决三个关键科学问题:①多期构造过程叠加与深部油气生成演化;②深部有效储层形成机制与发育模式;③深部油气复合成藏机制与油气富集规律。为此,建议采用油气成藏过程正演模拟和油气成藏过程反演剖析相结合的研究方法和"深部成藏条件—深部成藏机制—深部成藏规律"的技术主线,重点选择深部资源潜力最大的塔里木盆地和准噶尔盆地开展研究,期待形成和发展中国叠合盆地深部油气复合成藏理论,研发深部油气分布预测配套技术,促进中国西部深部油气勘探和储量的快速增长。

Based on comprehensive knowledge of deep reservoirs all over the world and petroleum geological features of superimposed basins in western China, this paper recognizes three key challenges of petroleum exploration in the deep of superimposed basins in western China. The first challenge is that hydrocarbons genera- ted in multi-phases mix together and their origins are not clear, making it hard to select leads. The second chal- lenge is that fractures and dissolved pores/cavities mix together in reservoirs and their origins are unclear, making it hard to predict favorable plays. The third challenge is that phases of hydrocarbon vary greatly and the distribution of hydrocarbon is influenced by high pressure and temperature, low porosity and permeability and several driving forces of migration, making it difficult to predict exploration targets using existing pool-forming theories. Therefore, to accelerate hydrocarbon exploration in the deep of superimposed basins in western Chi- na,we have to find answers to three key issues ： （i） multi-stage tectonic overprinting and deep hydrocarbon generation and evolution ; （ii） development mechanism and pattern of deep effective reservoirs ; （iii） compo- site pool-forming mechanism and accumulation pattern of hydrocarbons in deep strata. It is suggested to adopt a research method that integrates forward modeling with inversion analysis of hydrocarbon accumulation process and a technical route of ＂geological condition-mechanism-pattern of hydrocarbon accumulation＂. Tarim Basin and Junggar Basin can be choosen as the focus of study as they have the greatest deep petroleum resource po- tential. It is expected to develop theories on composite hydrocarbon accumulation in the deep of superimposed basins in western China and supporting techniques to predict hydrocarbon distribution. These new theories will promote hydrocarbon exploration and fast reserve growth in the deep of western China basins.