Qiang Hua, Liu Pengcheng, Li Guangpu, Fengmin Yang, Liu Xiaoxiao
Puyang Petrochemical Vocational and Technical College, Puyang, 457000, China.
Puyang Key Laboratory of Sound Field Assisted Oil and Gas Development, Puyang, 457000, China.
Sci Rep. 2024 Dec 28;14(1):31106. doi: 10.1038/s41598-024-82316-8.
Irreducible water saturation is an important factor affecting the development effect of low permeability reservoir. Using the self-developed ultrasonic generator, kerosene was used as simulated oil, the natural low-permeability siltstone cores with different physical properties in Zhongyuan Oilfield were selected for indoor oil displacement experiment, and the effect of ultrasonic action on the saturation of irreducible water in low-permeability reservoirs was evaluated. It was found that ultrasound can further reduce the saturation of irreducible water on the basis of oil flooding. The influence of different frequencies of ultrasound on the saturation of reservoir core irreducible water is different, and there is an optimal range of ultrasonic frequency: 17 kHz ~ 125 kHz. Increasing the ultrasonic power can effectively reduce the saturation of the core irreducible water in the low-permeability reservoir, and increasing the ultrasonic power can compensate for the adverse effects caused by the increase in frequency. With the increase of ultrasonic power, the thickness of the water film first decreases rapidly, and then gradually stabilizes, the highest drop could be 67.19%. The effect of ultrasound on the reduction of the saturation of irreducible water gradually deteriorates, with the increase of temperature, and at a higher temperature of 70 °C, the ultrasonic effect can still reduce the saturation of irreducible water. The effect of ultrasound on the saturation of irreducible water at low temperature is more intense, compared with high temperature, the irreducible water saturation can be reduced by 9.26%, and the ultrasonic effect is more suitable for low temperature treatment. The effect of ultrasound on the reduction of saturation of irreducible water in reservoirs with poor physical properties is more obvious.These studies are helpful for the systematic understanding of the effect of ultrasound on low permeability reservoirs and have positive implications for improving the development effect of low permeability reservoirs.
束缚水饱和度是影响低渗透油藏开发效果的重要因素。利用自主研发的超声波发生器，以煤油为模拟油，选取中原油田不同物性的天然低渗透粉砂岩岩心进行室内驱油实验，评价超声波作用对低渗透油藏束缚水饱和度的影响。研究发现，超声波在水驱基础上可进一步降低束缚水饱和度。不同频率超声波对油藏岩心束缚水饱和度的影响不同，存在一个超声波频率的最佳范围：17kHz～125kHz。增大超声波功率可有效降低低渗透油藏岩心束缚水饱和度，增大超声波功率可弥补频率升高带来的不利影响。随着超声波功率增大，水膜厚度先迅速减小，然后逐渐稳定，最大降幅可达67.19%。随着温度升高，超声波降低束缚水饱和度的效果逐渐变差，在70℃较高温度下，超声波作用仍可降低束缚水饱和度。超声波在低温下对束缚水饱和度的降低效果更强烈，与高温相比，束缚水饱和度可降低9.26%，超声波作用更适合低温处理。超声波对物性较差油藏束缚水饱和度的降低效果更明显。这些研究有助于系统认识超声波对低渗透油藏的作用效果，对改善低渗透油藏开发效果具有积极意义。
