石油与天然气地质 ›› 2025, Vol. 46 ›› Issue (4): 1107-1122.doi: 10.11743/ogg20250406

• 油气地质 • 上一篇    下一篇

全油气系统中储层润湿性与界面张力等关键参数变化特征及其分子动力学模拟

施砍园1,2,3(), 庞雄奇2,3(), 陈君青2,4, 陈掌星5, 王雷2,3, 蒲庭玉2,3, 鲍李银2,3, 惠沙沙6, 肖惠译2,3, 崔新璇2,3   

  1. 1.页岩油气富集机理与高效开发全国重点实验室,北京 102206
    2.油气资源与工程全国重点实验室,北京 102249
    3.中国石油大学(北京) 地球科学学院,北京 102249
    4.中国石油大学(北京) 理学院,北京 102249
    5.宁波东方理工大学 宁波数字孪生研究所,浙江 宁波 315200
    6.中国石油 勘探开发研究院,北京 100083
  • 收稿日期:2025-05-08 修回日期:2025-07-08 出版日期:2025-08-30 发布日期:2025-09-06
  • 通讯作者: 庞雄奇 E-mail:shikycup@163.com;pangxq@cup.edu.cn
  • 第一作者简介:施砍园(1996—),男,博士,油气藏形成机理与分布规律。E-mail: shikycup@163.com
  • 基金项目:
    中国石油科学研究与技术开发项目(2021DJ0101)

Variation characteristics and molecular dynamics simulation of key parameters including reservoir wettability and interfacial tension in the whole petroleum system

Kanyuan SHI1,2,3(), Xiongqi PANG2,3(), Junqing CHEN2,4, Zhangxing CHEN5, Lei WANG2,3, Tingyu PU2,3, Liyin BAO2,3, Shasha HUI6, Huiyi XIAO2,3, Xinxuan CUI2,3   

  1. 1.State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Efficient Development,SINOPEC,Beijing 102206,China
    2.State Key Laboratory of Petroleum Resources and Engineering,Beijing 102249,China
    3.College of Geosciences,China University of Petroleum (Beijing),Beijing 102249,China
    4.College of Science,China University of Petroleum (Beijing),Beijing 102249,China
    5.Ningbo Institute of Digital Twin,Eastern Institute of Technology,Ningbo,Ningbo,Zhejiang 315200,China
    6.Research Institute of Petroleum Exploration & Development,PetroChina,Beijing 100083,China
  • Received:2025-05-08 Revised:2025-07-08 Online:2025-08-30 Published:2025-09-06
  • Contact: Xiongqi PANG E-mail:shikycup@163.com;pangxq@cup.edu.cn

摘要:

由于受实验室条件和仪器性能制约,难以在高温、高压或超致密环境下准确测定储层岩石的润湿角、界面张力及孔喉半径,从而难以确定油气运聚过程中所遇到的毛细管力。为解决这一难题,采用分子动力学模拟方法,计算了较低温-压条件下方解石、蒙脱石、石英和长石矿物表面的润湿角,以及油-水和气-水界面张力。在模拟结果与实验数据高度吻合的基础上,将该方法拓展至高温、高压条件,模拟相应参数的变化。结合多元线性回归方法计算了储层孔喉半径,依据准噶尔盆地、鄂尔多斯盆地、松辽盆地的区域背景开展系统模拟研究,获得了中国高、中、低地温场条件下砂岩、火山岩和碳酸盐岩储层润湿角、界面张力以及孔喉半径随埋深的变化数据,建立了它们与含油气盆地温度和压力之间的定量关系。研究表明:① 随着温度的升高,方解石、蒙脱石、石英和长石的水润湿角逐渐减小,亲水性增强,压力的增加则使矿物的水润湿角增大,导致其亲水性减弱。整体而言,油藏中的方解石表现出油湿型,蒙脱石介于中性至水湿性之间,而石英和长石则主要呈水湿性。② 油-水界面张力随着温度的升高逐渐降低,但随着压力的增加逐渐上升;气-水界面张力随温度升高而降低,但随着压力的增加进一步减小。岩石孔喉半径与孔隙度和渗透率存在一定的关联性,表明储层的物性特征在流体运移过程中起到了重要作用。③ 不同矿物在不同地温场中的润湿性、界面张力及孔喉结构存在显著差异。随着地温梯度的增加,湿润角呈减小趋势。界面张力随地温梯度升高逐渐降低,削弱了油-水或气-水界面的分子作用力,提高了流体的流动性。

关键词: 储层孔喉半径, 毛细管力, 储层润湿角, 储层界面张力, 分子动力学模拟, 全油气系统定量评价, 油气运移

Abstract:

Accurately measuring the wetting angles, interfacial tension, and pore-throat radii of reservoir rocks under high temperature and pressure conditions or in ultra-tight reservoir environments remains challenging due to laboratory limitations and instrument constraints. These challenges complicate the determination of capillary pressure during hydrocarbon migration and accumulation. Given this, we calculate the wetting angles of the calcite, montmorillonite, quartz, and feldspar surfaces, as well as oil-water and gas-water interfacial tension, under relatively low temperature and pressure conditions using molecular dynamics simulation. After validating the high consistency between the simulation results and experimental data, we expand this method to high temperature and pressure conditions to simulate the corresponding variations in the above parameters. Furthermore, we calculate the pore-throat radii of reservoirs using the multiple linear regression method. Through systematic simulations based on the regional settings of the Junggar, Ordos, and Songliao basins, we obtain data on burial depth-varying wetting angles, interfacial tension, and pore-throat radii of sandstone, volcanic, and carbonate reservoirs under high-, medium-, and low-temperature geothermal fields in China. Accordingly, the quantitative relationships are established between these parameters and the temperature-pressure conditions of petroliferous basins. The simulation results indicate that the water wetting angles of calcite, montmorillonite, quartz, and feldspar decrease gradually with increasing temperature, suggesting enhanced hydrophilicity. In contrast, the water wetting angles of these minerals increase with pressure, leading to reduced hydrophilicity. Generally, in oil reservoirs, calcite tends to exhibit oil-wet behavior, montmorillonite shows neutrality to water-wet characteristics, while quartz and feldspar primarily display water-wet properties. The oil-water interfacial tension decreases gradually with rising temperature but increases progressively with pressure. In contrast, the gas-water interfacial tension decreases with rising temperature and declines further with increasing pressure. The pore throat radii of rocks show certain correlations with porosity and permeability, suggesting that reservoir physical properties play a significant role in fluid migration. The minerals exhibit significantly different wettability, interfacial tension, and pore-throat structures across varying geothermal fields. Their wetting angles trend downward with increasing geothermal gradient. Meanwhile, their interfacial tension also decreases gradually with increasing geothermal gradient, which reduces molecular interactions at oil-water or gas-water interfaces, thereby enhancing fluid mobility.

Key words: pore throat radius of the reservoir, capillary pressure, wetting angle of the reservoir, interfacial tension of the reservoir, molecular dynamic simulation, quantitative evaluation of the whole petroleum system, hydrocarbon migration

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