页岩油结垢堵塞水平井解堵阻垢有机酸体系  

Organic acid system for scale removal and prevention in scale-blocked horizontal shale oil wells

作　　者：岳渊洲 马红星 刘环宇 钟建伟 付继有 田伟东 王一航 刘银娟 YUE Yuanzhou;MA Hongxing;LIU Huanyu;ZHONG Jianwei;FU Jiyou;TIAN Weidong;WANG Yihang;LIU Yinjuan(Shale Oil Development Branch,PetroChina Changqing Oilfield Company,Qingyang 745000,Gansu,China;National Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields,Xi’an 710018,Shaanxi,China)

机构地区：[1]中国石油长庆油田页岩油开发分公司,甘肃庆阳745000 [2]低渗透油气田勘探开发国家工程实验室,陕西西安710018

出　　处：《石油钻采工艺》2024年第3期359-367,共9页Oil Drilling & Production Technology

基　　金：国家科技重大专项“鄂尔多斯盆地致密油开发示范工程”(编号:2017ZX05069);中国石油天然气股份有限公司重大专项“鄂尔多斯盆地页岩油勘探开发理论与关键技术研究”(编号:2021DJ1806)联合资助。

摘　　要：庆城油田长7页岩油藏采用长水平井压裂、增能、渗吸一体化的体积压裂技术实现规模效益开发,部分油井近井带结垢堵塞较为严重,导致产量下降较快,采用常规酸液体系恢复产能效果不理想。通过分析井筒冲砂返出的垢质胶结物的结垢特征、化学组分以及采出水离子的组成,探讨了地层结垢机理,针对性研发了适合庆城油田页岩油水平井解堵的长效复合有机酸解堵体系。研究结果表明,采出水中大量成垢离子在近井带结垢沉淀后包裹支撑剂并逐步填充颗粒缝隙,结垢类型以碳酸盐类为主,部分井出现硫酸钡锶垢。研发的复合有机酸解堵体系对垢样的溶蚀率达到80%以上,对N80钢材的腐蚀速率低至1.920 g/(m^(2)·h),防垢率大于85%,与地层水的配伍性较好,具有良好的长效解堵性能和防腐蚀性能。在庆城油田页岩油水平井现场应用5口,单井增油由3.5 t/d提高至5.1 t/d,有效期由190 d提升至450 d以上,取得了良好的增产效果,为同类页岩油藏的高效开发提供了技术借鉴。The Chang 7 shale oil reservoir in Qingcheng Oilfield has achieved large-scale economic development by applying technologies such as long horizontal well fracturing,energy boosting,and volumetric fracturing integrating imbibition.However,some oil wells experience significant scale deposition and blockage in the near-wellbore zone,leading to rapid decline in production,and conventional acid systems have proven ineffective for restoring productivity.By analyzing the scaling characteristics and chemical composition of the sand scale deposits recovered during sand washing,as well as the ion composition of the produced water,the mechanisms of formation scaling were investigated.Based on this analysis,a long-lasting composite organic acid system was developed,specifically targeting scale removal in horizontal shale oil wells in the Qingcheng Oilfield.The research results show that significant scaling ions in the produced water precipitate in the near-wellbore zone,encapsulating proppant and gradually filling pore spaces.The primary scale type is carbonate,with some wells found barium and strontium sulfate scales.The developed composite organic acid system achieved an over 80%dissolution rate of the scale samples,with a corrosion rate of only 1.920 g/(m^(2)·h)on N80 steel and a scale prevention efficiency exceeding 85%.The system showed good compatibility with formation water,offering excellent long-term scale removal and corrosion inhibition performance.Field application in five horizontal shale oil wells in the Qingcheng Oilfield shows that the average oil production for each well was increased from 3.5 t/d to 5.1 t/d,and the effective period was extended from 190 days to over 450 days,achieving remarkable production enhancement effect.This technology provides valuable guidance and experience for the efficient development of similar unconventional shale oil reservoirs.

关 键 词：页岩油 非常规油气 勘探开发 工程技术 长水平井 结垢堵塞 酸化 长效解堵体系 庆城油田 

分 类 号：TE358.5[石油与天然气工程—油气田开发工程]