隐蔽油气藏资源潜力预测方法探讨与初步应用

隐蔽油气藏形成演化过程和成因机理十分复杂,为了提高油气资源评价的可信度,为高层次的决策提供科学依据,应综合利用多种方法,如发现过程模型反演法、成藏门限理论正演计算法以及综合预测法。运用这些方法对济阳坳陷隐蔽油气藏的资源潜力进行了预测,结果显示:济阳坳陷还有20.24×10⁸t以上的隐蔽油气藏储量待发现,占剩余可探明储量的75%以上。其中,东营凹陷和沾化凹陷待发现隐蔽油气藏分别为7.83×10⁸t和3.53×10⁸t,车镇凹陷和惠民凹陷为3.78×10⁸t和3.52×10⁸t。平面上,隐蔽油气藏主要分布在储量丰度较高、探明储量较低的成藏体系内;层位上,沙河街组四段及其以上目的层勘探程度虽高仍是隐蔽油气藏储量增加的重点层位;类型上,岩性透镜体油气藏、不整合遮挡油气藏及古潜山油气藏是隐蔽油气藏今后勘探的重要类型。

Prediction method and its preliminary application in predicting resource poten tials of subtle oil/gas reservoirs

As formation, evolution and genetic mechanism of subtle oil/gas reservoirs are very complicated, various methods, such as discovery process model inversion, theoretical forward computation of hydrocarbon accumulation threshold and comprehensive prediction method, should be comprehensively used, so as to increase the reliability of potential evaluation and provide scientific basis for high level decision-makers. These methods are used to predict the potentials of subtle reservoirs in Jiyang depression. The prediction results show that there are still more than 2.024 billion tons reserves to be discovered in subtle reservoirs in the depression, which account for over 75% of the remaining provable reserves. The undiscovered possible reserves in subtle reservoirs in Dongying, Zhanhua, Chezhen and Huimin sags are 783 million tons, 353 million tons, 378 million tons and 352 million tons respectively. Laterally, subtle oil/gas reservoirs are mainly distributed in the reservoiring systems having relatively high abundance of reserves and relatively low proved reserves. Vertically, although the 4th member of Shahejie Formation and the targets above it have highly been explored, they are still the key horizons for discovering new reserves in subtle reservoirs. Lithologic lenticular reservoir, unconformity-screened reservoir and buried hill reservoir are the main types of subtle reservoirs to be explored in the future.