The experimental research has been implemented according to the production problem of oil formation soft blocking due to the non-hydrocarbon( resin/asphaltenes) deposition because the unreasonable control of in-situ combustion front during the gravity-assisted in-situ combustion production process. The reason analysis for soft bloc-king has been performed and the solution program has been provided. The experimental results demonstrate that the temperature and the air to oil ratio should be the main elements which can affect the deposition of non-hydrocarbon, the spontaneous ignition temperature is 257. 9℃, the three stages are existed in the process of oil oxidation to igni-tion, during the stage from 90℃ to 170℃, the CO2 content of end gas is increased with the increase of oil viscosi-ty owing to the increment of non-hydrocarbon content with the increase of air to oil ratio, but there is no non-hydro-carbon deposition;during the stage of 190℃ to 240℃, the amount of non-hydrocarbon deposition is extremely in-creased, the content of CO2 is approach to zero;the non-hydrocarbon content is decreased due to the high tempera-ture oxidation pyrolysis of crude oil with oxygen when the temperature is more than that of spontaneous ignition so that the oil viscosity is decreased. The analytical proofs combined with the experimental results demonstrate that the main reason of soft blocking is that the large scope of formation should be under the low temperature oxidation con-dition for 200℃ owing to slowly advance of in-situ combustion front which promotes the non-hydrocarbon deposition during the production process. The solution program has been given according to the four aspects of the optimization of well network/well spacing, the optimization of air injection rate and effluent gases control and assisted viscosity reduction.%针对重力火驱生产过程中因火线控制不当造成非烃（胶质/沥青质)沉积导致油层软卡无法生产的难题,进行了实验研究。对软卡原因进行了分析；并提出解决方案。实验结果表明：温度和空气油比是影响非烃沉积的主要因素,实验原油的自燃点为257.9℃,原油氧化到点燃可分为3个阶段,在90~170℃阶段,随着空气油比的增加,非烃含量增加,原油黏度增加,尾气CO2含量增加,但无非烃沉积；在190~240℃阶段,非烃沉积量急剧增大,CO2含量接近0；当温度超过自燃点时,由于原油与氧发生高温氧化裂解,非烃含量降低,原油黏度降低,尾气CO2含量急剧增加。结合实验结果,分析认为现场软卡的主要原因是火线扩展慢造成地层大范围处于200℃左右的低温氧化,而且生产过程中尾气的无限制外排,促进了非烃的沉积,对此,从优化井网/井距、优化注气量、合理控制尾气外排和降黏辅助四个方面提出了解决方案。
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