第38卷第4期 2017年8月
文章编号：1001-3873(2017)04-0466-04
新疆石油地质
XINJIANG PETROLEUM GEOLOGY DOI:10.7657/XJPG20170415
准东吉7井区注水井酸化预处理防膨技术
谢建勇，石彦，罗鸿成，李文波，谢俊辉
（中国石油新疆油田分公司准东采油厂，新疆阜康831511）
Vol. 38.No.4 Aug.2017
摘要：水敏性油蔗在注水开发中，黏土矿物膨胀是导致储集层渗透率下降、注水压力上升的主要原因。对于低渗透储集层而，即使加入防脚剂来抑制黏土矿物膨胀，减轻对渗透率的伤害，仍会发生注水压力上升，出现欠注甚至无法注水的现象。为实现长期有效注水，以吉7并区为例，开展了水敏储集层酸化预处理防膨技术研究。与无机和有机2 类防膨剂相比，采用酸化预处理，渗透率损失率最小，防膨效果的持久性和稳定性最好。选取了储集层类叙的2组注水并进行对比试验，与未酸化预处理井相比，投注前酸化预处理的注水井，并口启动压力低，注水压力上升速度慢，满足低渗水敏储集层长期注水的需求。在后续开发中应用22井次，有效抑制了注水压力上升速度，达到预期的目的。关键词：准喀尔盆地；吉木萨尔地区；水敏油藏；注水油藏；黏土膨胀；酸化预处理；防影技术
中图分类号：TE357.6
文献标识码：A
Anti-Swelling Technology for Acidizing Pretreatment in Water Injection Wells in
WellblockJi7,ZhundongOilfield
XIE Jianyong, SHI Yan, LUO Hongcheng, LI Wenbo, XIE Junhui
(Zhundong Oil Production Plant, Xinjiang Oilfield Company, PetroChina, Fukang, Xinjiang 831511, China)
Abstract: Clay swelling is the main reason causing reservoir permeability reduction and water-injection pressure rising during waterflood-ing development of water-sensitive reservoirs, Though anti-swelling agents can be added to inhibit clay swelling and to reduce damage to per-pe aoaraae osioasa eaado aro oa ae aa pe s nard oaae iea effective water injection and taking Wellblock Ji 7 for example, the study on anti-swelling technology for acidizing pretreatment is caried out for water-sensitive reservoirs, Compared with inorganic and organic anti-swelling agents, using acidizing pretreatment technology can get the minimum permeability loss, long-lasting and stable anti-swelling effeets, Two injector groups with similar reservoir conditions in Wellblock Ji 7 are selected to carry out a contrast test. The results show that compared with the non-acidized pretreatment wells, the injectors with acidiz-ing pretreatment before water injection are featured with low wellhead start pressure and slowly rising of water injection pressure, which can meet the demand of long-term water injection in low-permeability and water-sensitive reservoirs. Field applications of the pretreatment tech-nology in 22 wells show that the technology can effectively slow down the rising of water injection pressure and good effects have been gained. Keywords: Junggar basin; Jimsar area; water- sensitivity reservoir; waterflooding reservoir; clay swelling: acidizing pretreatment; anti -
swelling technology
水敏性油藏注水开发中，由于低矿化度注人水与孔喉间的黏土矿物接触，黏土矿物发生水化膨胀，导致孔隙、喉道缩小，渗透率下降，注水井压力上升，欠注、注不进的现象普遍，地层压力难以保持，严重影响开发效果-"。因此，通常采用防膨注水，即在注入水中加人防膨剂来抑制黏土矿物膨胀，减缓注水压力的上升速度，但从经济效益上考虑，防膨剂的浓度不可能过高，加上防膨剂自身对储集层也有伤害(5-6)，因而，即使采用了防膨注水，从长期来看，仍然不能避免注水井欠注、注不进现象的发生。
准东地区的多个水敏性油藏，便出现了这种情况，如沙南油田Pwti油层，平均渗透率2mD.水敏指数0.85，采用变浓度连续注人方式进行防膨，投注初期平均注水压力13MPa，注水5a后，油藏累计注水量
收稿日期：2016-10-31
修订日期：2017-06-02
不足0.2PV，注水压力已上升到16~20MPa，年均压力上升1MPa，注水干线压力20MPa，有40%的井出现欠注或注不进。后期采取酸化、压裂等多种增注工艺，也难以有效解决欠注问题"，严重影响了开发效果。新开发的吉7井区，同样属于低渗水敏储集层，为满足长期注水的需要，开展了相关研究。由于酸和黏土矿物能发生化学反应，破坏黏土矿物的阳离子交换能力，改变黏土矿物的本性，反应后的残留物主要成分为SiO2，从而降低黏土矿物的膨胀性能。基于这一认识，针对性地开展了酸化预处理防膨技术研究，为后期注水开发提供依据。
吉7井区储集层特征
吉7井区是准东地区近年发现的一个大型稠油
作者简介：谢建勇（1968-），男，广东梅县人，高级工程师.油气田开发，（Tel)09943832044(E-mail)xiejypetrochina.com.en 万方数据