摘要
酸化是低渗砂岩油藏有效开发的主要改造手段之一。塔中志留系储层小层多,非均质性强,酸化中酸液易进入高渗层,导致低渗层改造欠缺,目前尚无合适的砂岩转向酸化技术。本文采用了可完全水溶降解的清洁暂堵粉末,并配合螯合酸解决了非均质砂岩储层均匀酸化难题。通过并联岩心酸化流动仪,研究了清洁暂堵粉末封堵特性和不同级差下暂堵转向酸化能力。室内实验结果表明,清洁暂堵粉末降解主要受温度控制,在超过90℃后完全降解,降解后溶液清澈透明,且呈酸性,有效提升岩心渗透率20%。浓度为0.1%的暂堵粉末随螯合酸注入岩石后,能够形成内外阻挡层,增加暂堵表皮系数,最大封堵压差可达1.87 MPa,是单纯注螯合酸酸的6.7倍。并联岩心酸化实验表明100目清洁暂堵粉末在0.1%使用浓度下适用于渗透率级差小于15的储层,可有效降低岩心渗透率非均质差异,提高低渗岩心改造程度。此外,在塔中11-9井酸化施工中,暂堵转向酸化后增压效果明显,酸化后产量大幅增加。现场试验及应用证明,暂堵转向酸化技术在志留系储层取得了良好的增产改造效果,对长井段非均质砂岩储层酸化均匀改造具有重要的借鉴意义。
Acidizing constitutes a pivotal enhancement strategy for the effective exploitation of low-permeability sandstone oil reservoirs.The Silurian reservoirs in the Tarim Basin,characterized by numerous thin layers and pronounced heterogeneity,present challenges in acid treatment;specifically,acid fluids preferentially enter high-permeability layers,resulting in inadequate stimulation of low-permeability strata.Current techniques for sandstone reservoir acid diversion remain insufficient.This study introduces a fully water-soluble and degradable clean temporary plugging powder,combined with chelating acid,to address the uniform acidizing challenge in heterogeneous sandstone reservoirs.The research employs a parallel core acidizing flow instrument to investigate the blocking characteristics of the clean temporary plugging powder and its acid diversion capabilities under various differential pressures.Laboratory experiments demonstrate that the degradation of this powder is predominantly temperature-controlled,with complete degradation occurring above 90℃,resulting in a clear,acidic solution and effectively enhancing core permeability by 20%.A 0.1%concentration of the plugging powder,when injected with chelating acid into the rock,forms an internal and external barrier layer,increasing the temporary plugging skin factor.The maximum sealing pressure differential achieved is 1.87 MPa,6.7 times that of chelating acid alone.Parallel core acidizing experiments reveal that 100-mesh clean temporary plugging powder at a 0.1%concentration is suitable for reservoirs with a permeability gradient less than 15,effectively reducing the heterogeneity in permeability and improving the transformation of low-permeability cores.Moreover,in the acidizing operation of well 11-9 in the Tarim Basin,the temporary plugging and diversion technique showed a notable increase in pressure and a substantial enhancement in production post-acidizing.Field trials and applications confirm that the temporary plugging and diversion acidizing technique achieves commendable production enhancement and transformation in Silurian reservoirs,offering significant insights for the uniform acidizing of long sections in heterogeneous sandstone reservoirs.
作者
王庆
周福建
阳丹丹
谭艳新
于森
姚二冬
李福远
WANG Qing;ZHOU Fujian;YANG Dandan;TAN Yanxin;YU Sen;YAO Erdong;LI Fuyuan(State Key Laboratory of Petroleum Resources and Prospecting·China University of Petroleum,Beijing 102249)
出处
《钻井液与完井液》
CAS
北大核心
2024年第5期686-694,共9页
Drilling Fluid & Completion Fluid
基金
国家自然科学基金“极限射孔结合动态封孔的多缝均衡起裂与均匀扩展控制方法研究”(52174045)
国家自然科学基金“纳米乳液在致密砂岩储层中的吸附特性及其解水锁机制研究”(52004306)
中国石油天然气集团有限公司-中国石油大学(北京)战略合作科技专项“准噶尔盆地玛湖中下组合和吉木萨尔陆相页岩油高效勘探开发理论及关键技术研究”(ZLZX2020-01)。
关键词
强非均质性
转向酸化
清洁暂堵
均匀布酸
Strong heterogeneous
Diverted acidification
Cleaning temporary plugging
Uniformly distributed acid
作者简介
第一作者:王庆,在读博士,就读于中国石油大学(北京),现在从事酸化压裂储层改造。E-mail:2021311217@student.cup.edu.cn。
