注热化学流体吞吐解除岩石储层反凝析伤害评价  

Evaluation of thermalchemical fluid huff and puff to relieve retrograde condensation damage in reservoirs

作　　者：文开丰[1] 李浩[1] 龚浩研[1] 王超[1] 袁丹[1] 李博远 邓宝康 WEN Kaifeng;LI Hao;GONG Haoyan;WANG Chao;YUAN Dan;LI Boyuan;DENG Baokang(No.2 Gas Production Plant of Changqing Oilfield Company,PetroChina,Yulin City,Shaanxi Province,719000,China;Sichuan OGT Technology Development of Oilfield Co.,Ltd.,Chengdu City,Sichuan Province,610041,China)

机构地区：[1]中国石油长庆油田分公司第二采气厂,陕西榆林719000 [2]四川奥吉特油田科技开发有限公司,四川成都610041

出　　处：《油气地质与采收率》2024年第1期153-162,共10页Petroleum Geology and Recovery Efficiency

基　　金：国家自然科学基金项目“陆相页岩油藏CO_(2)压裂复杂缝网形成机制及增产机理”(5207042143)。

摘　　要：为长期有效解除凝析气藏反凝析带来的储层伤害,提出了一种注热化学流体吞吐解除凝析油堵塞孔喉的新方法。针对致密砂岩、碳酸盐岩和页岩3类岩石,开展了注热化学流体吞吐岩心驱油实验,评价了热化学流体解除凝析油堵塞的可行性,并基于核磁共振技术分析了吞吐前后3类岩石微观孔隙结构的变化特征,明确了热化学流体解除反凝析伤害机理。实验结果表明,热化学流体(NH_(4)Cl和NaNO_(2))在乙酸溶液催化下能够迅速释放大量气体和蒸汽,提高岩心压力和温度,降低原油黏度,使凝析油由液态转变为气态,减小渗流阻力。致密砂岩、碳酸盐岩和页岩岩心注热化学流体吞吐累积凝析油采出程度分别为65.7%,73.9%和46.3%。其中,致密砂岩和碳酸盐岩岩心仅需2轮吞吐即可有效清除55.5%和67.6%的凝析油堵塞。而页岩岩心需要延长焖井时间及增加吞吐次数方能提高凝析油的采出程度。热化学流体吞吐后,致密砂岩、碳酸盐岩和页岩岩心平均孔径分别由0.37,1.04和0.0021μm增大至0.84,2.04和0.0058μm。热化学流体吞吐效果是注CH_(4)吞吐和注甲醇吞吐效果的1.85和1.32倍。In order to effectively eliminate the reservoir damage caused by retrograde condensation in condensate gas reservoirs,a new method for removing the plugging pore throat of condensate oil by thermochemical fluid huff and puff was proposed.For tight sandstone,carbonate,and shale reservoirs,a core oil displacement experiment of thermochemical fluid huff and puff was carried out to evaluate the feasibility of removing condensate plugging by thermochemical fluid.Based on nuclear magnetic resonance technology,the change characteristics of the micro-pore structure of the three types of reservoirs before and after huff and puff were ana-lyzed,and the mechanism of removing retrograde condensate damage by thermochemical fluid was clarified.The experimental re-sults show that thermochemical fluids(NH_(4)Cl and NaNO_(2))can rapidly release a large amount of gas and steam under the catalysis of acetic acid,increase the core pressure and temperature,reduce the viscosity of crude oil,make the condensate change from liq-uid to gas,and reduce the flow resistance.The cumulative condensate recoveries of tight sandstone,carbonate,and shale cores by thermochemical fluid huff and puff are 65.7%,73.9%,and 46.3%respectively.Among them,two rounds of huff and puff can effec-tively remove 55.5%and 67.6%of condensate plugging in tight sandstone and carbonate samples respectively.However,the shale core needs to extend the soak time and increase the number of huff and puff to improve the recovery of condensate.After the thermo-chemical fluid huff and puff,the average pore size of tight sandstone,carbonate,and shale cores increases from 0.37,1.04,and 0.0021μm to 0.84,2.04,and 0.0058μm respectively.The thermochemical fluid huff and puff effect is 1.85 and 1.32 times that of CH_(4) injection and methanol injection respectively.

关 键 词：热化学流体 致密砂岩 碳酸盐岩 页岩 反凝析 孔隙结构 

分 类 号：TE348[石油与天然气工程—油气田开发工程]