围岩含油饱和度控制岩性油藏成藏的物理模拟

Physical simulation of the control of source rock oil saturation on forming lithological oil pools

东营凹陷已发现的岩性油藏基本处于沙四上亚段、沙三段烃源岩的排烃门限范围内,烃源岩的排烃范围及排烃强度对岩性圈闭成藏有明显控制作用。为研究不同围岩含油饱和度对岩性圈闭成藏的控制作用,在剖析东营凹陷岩性油藏的基础上,使用三维高温高压岩性油藏成藏实验设备,通过计算机和可视化技术数据采集系统,采集实验温度、压力、位移和电阻数据,通过标定实验,得出砂体模型内含水饱和度及含油饱和度与其电阻的关系,进行数学拟合,将模拟实验获得的电阻转换成含油饱和度,用以研究含油饱和度与实验条件的关系。物理模拟实验结果表明,在一定压力条件下,围岩含油饱和度越大,砂体中含油饱和度就越大,越有利于砂体的成藏。模拟实验中围岩电阻和砂体电阻变化规律相反,围岩电阻呈非线性降低,而砂体的电阻呈非线性增加,并且电阻的变化率都是先快后慢,最后达到平衡。

The lithological oil pools discovered in Dongying Sag are distributed under the depth of hydrocarbon expulsion threshold of Es3 and Es4. and the formation of the oil pools is controlled by hydrocarbon expulsion scopes and intensity distinctly. The control of oil saturation in shoulder-bed on formation of lithological oil pools was studied by using the three- dimensional high-temperature and high-pressure simulation. The relationships between resistance and oil saturation and water saturation were acquired by calibration experiment. The resistance data of simulation experiments were transformed to oil saturation data. The control of oil saturation on formation of lithological oil pools can be demonstrated. The results showed a non-linear decrease of shoulder-bed resistance and a non-linear increase of sandbodies resistance, and the rate of resistance is fast initially, slow afterwards, and steady finally. With a certain pressure, the higher shoulder-bed oil saturation is, the higher oil saturation in sandbodies is, and the more favorable it is for the sandbodies to accumulate oil.