珠江口盆地油气勘探新进展与潜力区带预测

Recent advancements in oil and gas exploration and potential zone prediction in Pearl River Mouth Basin

  • 摘要: 珠江口盆地新生界油气资源丰富,探明储量增长迅速。低角度拆离型断层控烃、古潜山走滑断裂与风化淋滤控储、深水多类型储集体富集等地质认识创新为盆地勘探迎来新机遇。然而,该盆地地质结构复杂、目标类型多样,增加了勘探的难度。因此,在勘探理论突破的指导下,重新评估盆地新生界油气地质条件、明确油气勘探潜力区带至关重要。通过综合分析珠江口盆地的构造—沉积耦合作用、烃源岩条件和储层条件评价、油气运移特征,开展了盆地不同区带的油气地质成功概率评估,并计算了新生界总地质资源量。珠江口盆地在新生代经历了裂陷期、裂后拗陷期及构造活化期的构造演化,形成了陆相沉积、海陆过渡相沉积及浅海相沉积充填特征,控制了古近系两套主要烃源岩及陆、海相两套储层。浅水区的陆丰、惠州、文昌凹陷油气地质条件优越,含油气概率超过20%,地质风险较低,划分为Ⅰ类有利区带。新生界总地质资源量约为138亿吨,其中石油占71%,天然气占29%。基于区带评价和勘探实例,未来应重点加强深层古潜山、古近系及深水油气藏的勘探,特别是在恩平、开平、白云凹陷寻找低角度拆离型油气藏,文昌、阳江凹陷寻找深层走滑断裂潜山裂缝型油气藏,白云、荔湾凹陷寻找深水油气藏。这些凹陷有望成为珠江口盆地未来油气勘探的重要潜力区带。

     

    Abstract: The Pearl River Mouth Basin (PRMB) is rich in oil and gas resources in the Cenozoic, with proven reserves growing rapidly. Geological breakthroughs, such as the identification of hydrocarbon accumulation controlled by low-angle detachment faults, strike-slip fault-controlled reservoirs in buried hills through weathering and leaching processes, and multi-type reservoir enrichment in deep-water areas, have offered new insights into exploration targets in PRMB. However, the complex geological structure and diverse target types in the basin increase the difficulty of exploration. Therefore, under the guidance of breakthroughs in exploration theory, it is crucial to reassess the Cenozoic oil and gas geological conditions in PRMB and identify potential oil and gas exploration zones. Through comprehensive analysis of the tectonic-sedimentary coupling relationships, hydrocarbon source rock and reservoir conditions, and oil and gas migration characteristics in PRMB, the oil and gas-bearing probability in different zones of PRMB was evaluated, and the total geological resource amount of the Cenozoic was calculated. The PRMB experienced significant tectonic evolution during the Cenozoic, characterized by rifting, post-rift depression, and structural activation. This evolution resulted in the formation of continental, transitional, and shallow marine sedimentary filling features, which controlled the development of two Paleogene hydrocarbon source rocks and two sets of continental and marine reservoirs. The oil and gas geological conditions in the shallow-water areas of the Lufeng, Huizhou, and Wenchang sags were favorable, with oil and gas-bearing probability exceeding 20% and relatively low geological risks. Therefore, these areas were classified as Class Ⅰ favorable zones. The total geological resource amount of the Cenozoic was approximately 13.8 billion tons, with oil accounting for 71% and natural gas 29%. Based on zone evaluation and actual exploration cases, future exploration should focus on buried hills, Paleogene, and deep-water oil and gas reservoirs, especially searching for those in low-angle detachment faults of the Enping, Kaiping, and Baiyun sags, fractured reservoirs controlled by deep strike-slip faults in buried hills of the Wenchang and Yangjiang sags, and deep-water reservoirs in the Baiyun and Liwan sags. These sags are expected to become important potential exploration zones for future oil and gas exploration in PRMB.

     

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