稠油油藏吞吐后转氮气泡沫驱

NITROGEN FOAM FLOODING INVERTED FROM HUFF-AND-PUFF FOR HEAVY OIL RESERVOIRS

氮气泡沫驱能有效改善稠油油藏蒸汽吞吐和水驱后期的开发效果。以辽河油田某区块莲花油层稠油油藏为对象,开展氮气泡沫驱研究。通过岩心驱替实验,确定了氮气泡沫驱的最佳气液比;利用油藏数值模拟技术,建立了三维地质模型,进行了目标区块历史拟合。在此基础上,优化了氮气泡沫驱注采设计方案,预测对比了方案实施后的效果。研究结果表明:目标区块宜采用注泡沫2个月后开井生产4个月的周期氮气泡沫驱开发方式,注入最佳气液比为1.3:1,发泡剂最佳使用质量分数为0.45%,单井注入速度为45 m^3/d;与同期注水开发预测结果相比,周期氮气泡沫驱的预测阶段采收率可提高6.09%。氮气泡沫驱技术可显著提高该区块稠油油藏采收率。

Nitrogen foam flooding can effectively improve the development results for the huff-and-puff and later water flooding of heavy oil reservoirs. Taking Lotus Layer of the heavy oil reservoirs in a block of Liaohe Oilfield as the study target, the nitrogen foam flooding study is conducted. Through the experiment of core displacement, the optimal ratio of the gas to liquid for the foam flooding is determined ; with the help of the numerical simulating technique of an oil reservoir, the 3 D geological model is established and then the history match is engaged for the target block. On the basis of the above, the design programs on the injection and production of the foam flooding are optimized, finally the effects of the program implementation are predicted and contrasted. The studies show that the development scheme i. e. the cyclic foam flooding of producing for 4 months after 2-month foam flooding is suitable for the target block, the optimal injection-production gas-to-liquid ratio is 1.3： 1, the mass fraction most optimal used in the foaming agent is 0.45%, the injection rate of the individual well is 45 ma/d; comparing with the predicted results of the water injection development in the same period, the forecast stage recovery of cyclic nitrogen foam flooding can be enhanced by 6.09%. Obviously, the technique of nitrogen foam flooding can remarkably improve the oil recovery of the heavy oil reservoirs in the block.