Analysis of SAGD Steam Chamber Expansion and Production Characteristics of Thick Layer and Thin Layer

Abstract The development of offshore heavy oil by water injection faces technical bottlenecks such as high injection production flow ratio, rapid increase in water content, and low recovery rate. This study focuses on the temperature sensitivity characteristics of heavy oil, and systematically investigates the evolution law of reservoir temperature field and the optimization mechanism of development effect under hot fluid injection conditions through a combination of physical experiments and numerical simulations. Based on the principle of similarity, a two-dimensional visual physical model is established, and innovative temperature field characterization parameters such as effective sweep coefficient, regularization factor, and high-temperature zone plane expansion rate are proposed to reveal the mechanism of the effect of injection medium, rhythm characteristics, and injection timing on sweep efficiency. Experimental studies have shown that compared to conventional hot water flooding, hot water composite flooding can increase the effective sweep coefficient by 91% (15.05% → 28.71%); The vertical expansion ability of the high-temperature zone in the anti rhythmic reservoir is enhanced, and the oil displacement efficiency is improved by 1.5 percentage points; Low water content hot water injection can effectively inhibit the development of water channeling channels. Numerical simulation quantitatively confirms that increasing the injection temperature by 10°C can increase the proportion of high-temperature heating zone by 3.2%; The injection rate is positively correlated with the thermal cavity expansion rate (R 2 =0.93); The presence of high osmotic bands reduces thermal waves and efficiency by 18% -25%. The research results provide theoretical basis and technical path for optimizing the thermal development parameters of offshore heavy oil.