Browsing by Author "Yang, Min"

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    Characterization of the Dynamic Imbibition Displacement Mechanism in Tight Sandstone Reservoirs Using the NMR Technique
    (2020-12-16) Dou, Liangbin; Yang, Min; Gao, Hui; Jiang, Dongxing; Liu, Chenglu
    An experimental technique is developed to investigate the dynamic imbibition displacement mechanism in tight sandstone formations of the Yanchang group of the Ordos basin. By combining the dynamic imbibition core flooding experiments and NMR technique, the effects of the injection volume and rate on displacement efficiency are investigated. Moreover, the displacement efficiency of dynamic imbibition is compared with that of static imbibition. This study gains insights into the micromechanisms of dynamic imbibition in tight sandstone formations. It is found that the relative displacement efficiency of dynamic imbibition increases with the increase of injection volume. But the increment amplitude decreases with the increase of injection volume. With the same injection volume, the core displacement efficiency of dynamic imbibition with high permeability is obviously improved. However, the core displacement efficiency decreases rapidly with the increase of injection volume. Optimal injection volumes are recommended for tight sandstone formations with different permeabilities. With the increase of the displacement rate, the core displacement efficiency of dynamic imbibition shows a trend of first rising and then declining. There exists an optimal displacement rate in dynamic imbibition displacement, and the optimal displacement rate almost linearly increases with the increase of core permeability. The static imbibition displacement efficiency increases with the increase of soaking time, but the increment amplitude slows down obviously. The displacement efficiency of static imbibition in small pores is higher than that of dynamic imbibition. The displacement efficiency of dynamic imbibition in large pores or microcracks is significantly higher than that of static imbibition. This study provides theoretical support for the optimization and improvement of the waterflooding recovery process in tight sandstone reservoirs.
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    Numerical Modelling of Hybrid Steam and Combustion Recovery Process for Oil Sands
    (2019-07-30) Yang, Min; Chen, Zhangxin; Harding, Thomas Grant; Dong, Mingzhe; Hassanzadeh, Hassan; Lines, Larry R.
    Steam Assisted Gravity Drainage (SAGD) is a proven commercial thermal technology to recover high viscosity bitumen from oil sands resources, but SAGD has a few main limitations. In Situ Combustion (ISC) provides an alternative to steam injection with the advantages of lower cost and higher energy efficiency. In recent years, a hybrid process combining both steam and air or oxygen injection has been considered with the expectation to combine the advantages of both the steam and combustion recovery processes. Before application of such a hybrid process in the field, it is advantageous to simulate its performance using a numerical model and thus optimize its overall application. A comprehensive reaction kinetics model based on characterization of the bitumen into Saturates, Aromatics, Resins, and Asphaltene (SARA) fractions has been developed to simulate the ISC process with pre-steamed Athabasca oil sands. Critical observations were first obtained from a set of laboratory Ramped Temperature Oxidation (RTO) tests. Based on observations from the experiments, a modified reaction kinetics model has then been proposed consisting of Low Temperature Oxidation (LTO), thermal cracking, and High Temperature Oxidation (HTO). The reaction kinetics model was further tuned to match Combustion Tube tests results as these tests were associated with co-injection of steam and enriched air on a larger scale than the RTO experiments. The excellent match between the measured and simulated results indicate that the displacement mechanisms and key chemical reactions have been captured. Subsequently, field-scale simulation of the hybrid steam and combustion process, using the reaction kinetics model developed, was performed. In order to improve the computational efficiency of the simulation, a dynamic gridding feature was applied. By comparing the simulation results from a fine grid model and a dynamic gridding model, it was found that a temperature gradient is the best criterion to control dynamic gridding. Operating parameters were investigated, including well configuration, O2 concentration, and steam concentration. For all simulation scenarios considered in this work, the cSOR in the hybrid process was improved and this illustrates the main advantage of the hybrid steam and ISC process over steam-only injection as in SAGD.