Galliero Guillaume, Bataller Henri, Bazile Jean-Patrick, Diaz Joseph, Croccolo Fabrizio, Hoang Hai, Vermorel Romain, Artola Pierre-Arnaud, Rousseau Bernard, Vesovic Velisa, Bou-Ali M Mounir, Ortiz de Zárate José M, Xu Shenghua, Zhang Ke, Montel François, Verga Antonio, Minster Olivier
Laboratoire des Fluides Complexes et leurs Réservoirs-IPRA, E2S, UMR5150, Univ Pau & Pays Adour/CNRS/TOTAL, 64000 Pau, France.
Centre National d'Etudes Spatiales (CNES) 2, Place Maurice Quentin, 75001 Paris, France.
NPJ Microgravity. 2017 Aug 11;3:20. doi: 10.1038/s41526-017-0026-8. eCollection 2017.
Compositional grading within a mixture has a strong impact on the evaluation of the pre-exploitation distribution of hydrocarbons in underground layers and sediments. Thermodiffusion, which leads to a partial diffusive separation of species in a mixture due to the geothermal gradient, is thought to play an important role in determining the distribution of species in a reservoir. However, despite recent progress, thermodiffusion is still difficult to measure and model in multicomponent mixtures. In this work, we report on experimental investigations of the thermodiffusion of multicomponent -alkane mixtures at pressure above 30 MPa. The experiments have been conducted in space onboard the Shi Jian 10 spacecraft so as to isolate the studied phenomena from convection. For the two exploitable cells, containing a ternary liquid mixture and a condensate gas, measurements have shown that the lightest and heaviest species had a tendency to migrate, relatively to the rest of the species, to the hot and cold region, respectively. These trends have been confirmed by molecular dynamics simulations. The measured condensate gas data have been used to quantify the influence of thermodiffusion on the initial fluid distribution of an idealised one dimension reservoir. The results obtained indicate that thermodiffusion tends to noticeably counteract the influence of gravitational segregation on the vertical distribution of species, which could result in an unstable fluid column. This confirms that, in oil and gas reservoirs, the availability of thermodiffusion data for multicomponent mixtures is crucial for a correct evaluation of the initial state fluid distribution.
混合物中的成分分级对评估地下层和沉积物中烃类的开采前分布有很大影响。热扩散是由于地热梯度导致混合物中物种发生部分扩散分离的现象，被认为在确定储层中物种分布方面起着重要作用。然而，尽管最近取得了进展，但热扩散在多组分混合物中仍然难以测量和建模。在这项工作中，我们报告了在压力高于30MPa时多组分烷烃混合物热扩散的实验研究。实验是在中国实践十号卫星上进行的，以便将研究的现象与对流隔离开来。对于两个可开采单元，一个包含三元液体混合物，另一个包含凝析气，测量结果表明，相对于其他物种，最轻和最重的物种分别倾向于向热区和冷区迁移。这些趋势已通过分子动力学模拟得到证实。所测得的凝析气数据被用于量化热扩散对理想化一维储层初始流体分布的影响。所得结果表明，热扩散倾向于显著抵消重力分异对物种垂直分布的影响，这可能导致流体柱不稳定。这证实了，在油气藏中，多组分混合物的热扩散数据对于正确评估初始状态流体分布至关重要。
