三塘湖致密油藏考虑扩散氮气吞吐参数优化  

Parameters optimization of nitrogen gas huff and puff in Santanghu tight reservoir

作　　者：汪周华[1] 顾蒙[1] 郭平[1] 桑廷义 袁昭 廖华伟 孟迪[3] 

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室,四川成都610500 [2]中国石油吐哈油田分公司,新疆哈密839009 [3]西南石油大学地球科学与技术学院,四川成都610500

出　　处：《油气藏评价与开发》2017年第5期16-19,25,共5页Petroleum Reservoir Evaluation and Development

基　　金：国家自然科学基金面上项目"考虑毛管压力和吸附影响的CO2-原油非平衡扩散理论及分子动力学研究"(51374179);国家留学基金"西部地区人才培养特别项目"(201508515157)

摘　　要：氮气单井吞吐是吐哈三塘湖致密油藏采用的重要增产技术措施,分子扩散是影响注气时气—油相之间质量传递过程的重要参数,而常规数值模拟均忽略该参数的影响。以M56-X井为例,运用数值模拟方法,优选该井吞吐注采参数,同时分析分子扩散对注采参数及注气效果的影响。研究表明:扩散作用对注气量、注气速度、采液速度变化规律影响不大,但对闷井时间的影响较显著;闷井时间不足时,考虑扩散后氮气降黏效果减弱、增产油量减少,忽略扩散则过高估计了吞吐注气效果;以最优参数注气,保证足够长闷井时间,忽略扩散,增油600 t、换油率2.027 t/t,考虑扩散增油为593 t、换油率2.004 t/t,两者增油量接近,此时可忽略扩散影响。研究成果对高效开发此类致密油藏有重要的借鉴意义。The single well nitrogen gas huff and puff is an important stimulation technique for Santanghu tight reservoir of Tuha oilfield. The molecular diffusion is an important parameter influencing the mass transfer between the gas and oil phase during the gas injection. However, the conventional numerical simulation usually neglect this effect. Taking well M56-X for an example, the influences of the molecular diffusion on the injection/production parameters and gas injection effects were analyzed in the meantime by using the numerical simulation method and the optimal injection and production parameters of nitrogen gas huff and puff. The researches show that the molecular diffusion has little influence on gas injection volume, gas injection rate and production rate, nevertheless, molecular diffusion has obvious effects on the soak time. When the soak time is insufficient, the reducing of the viscosity effects after molecular diffusion and oil production reduction are considered, and the molecule diffusion is neglected in conventional reservoir simulation, thus, the nitrogen gas huff and puff effect is overestimated. By the adoption of optimal nitrogen gas and long enough soak time, with the neglecting of the molecule diffusion, oil increment is 600 tons and oil exchange ratio is 2.027 t/t, in addition, when considering the molecule diffusion, the oil increment is 593 tons and oil exchange ratio is 2.004 t/t. These two results are similar and the effects of molecule diffusion can be neglected. The results help for the effective development of the similar tight reservoirs.

关 键 词：致密油藏 单井吞吐 扩散作用 参数优化 注采参数 

分 类 号：TE357.45[石油与天然气工程—油气田开发工程]