页岩油高气油比水平井复杂垢型防垢技术  

Anti-scaling technology for complex scale types in shale horizontal oil wells with high gas-oil ratio

作　　者：吴霞 党永潮 赵晖 张鑫 刘小欢 贾剑波 陈臻 龙学莉 WU Xia;DANG Yongchao;ZHAO Hui;ZHANG Xin;LIU Xiaohuan;JIA Jianbo;CHEN Zhen;LONG Xueli(Shale Oil Development Division,Changqing Oilfield Company,PetroChina,Qingyang 745000,Gansu,China;National Engineering Laboratory for Low-Permeability Oil and Gas Field Exploration and Development,Xi’an 710018,Shaanxi,China;Qingyang Company,Xi’an Changqing Chemical Group Co.,Ltd.,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 [3]西安长庆化工集团有限公司庆阳分公司,陕西西安710018

出　　处：《石油钻采工艺》2024年第3期368-376,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页岩油水平井开发以来,井筒结垢程度远高于同区域其它层系,一定程度上影响了开井时率和检泵周期。页岩油水平井套压分布在0.5~2.0 MPa,生产气油比较高(大于100 m^(3)/t),井口药剂加注难度较大;井筒垢型复杂可变,单一的阻垢剂已不能满足现场使用要求。因此,亟需进行页岩油井筒结垢机理及高效防垢工艺研究。通过开展页岩油不同开发阶段流体性质、垢型分析,明确结垢特征及主要影响因素,投产初期垢质主要为碳酸亚铁,后期生成垢质以碳酸钙、硫酸钙为主。通过研发页岩油复合阻垢剂及井下点滴加药装置,现场试验油井见效5口,结果表明连续监测采出液磷元素含量28~40 mg/L,井下点滴加药装置释放药剂连续且稳定;单井结垢速率由3.4 mm/a下降至0.5 mm/a,检泵周期由155 d延长至362 d,检泵周期延长162.2%。研究形成了页岩油水平井井筒长效防垢技术,为页岩油的高效开发和稳产提供了技术指导和参考经验。Since the commencement of horizontal well development in the Chang 7 shale oil reservoir in Qingcheng Oilfield,the degree of scaling in the wellhole has been significantly higher than in other formations within the same region.This scaling issue has adversely affected the open flow rate and the pump inspection cycle.The horizontal shale oil wells exhibit a casing pressure distribution ranging from 0.5 to 2.0 MPa and a high gas-oil ratio(greater than 100 m^(3)/t),complicating the chemical injection process at the wellhead.The wellhole scale types are complex and variable,rendering single-type scale inhibitors inadequate for field applications.Thus,research on the scaling mechanism in shale oil wellholes and the development of efficient anti-scaling technologies are becoming imperative.By analyzing the fluid properties and scale types at different stages of shale oil development,the characteristics and key influencing factors of scaling were identified.In the initial production stage,the primary scale composition is ferrous carbonate,while in the later stages,calcium carbonate and calcium sulfate become predominant.A composite scale inhibitor tailored for shale oil and a downhole drip doser were developed and tested in 5 field wells.The results show that continuous monitoring of phosphorus content in the produced fluids ranged from 28 to 40 mg/L,with the downhole drip injection device ensuring a stable and continuous release of chemicals.The scaling rate per well decreased from 3.4 mm/a to 0.5 mm/a,and the pump inspection cycle extended from 155 days to 362 days,a 162.2%increase in pump inspection intervals.This research established a long-term anti-scaling technology for horizontal shale oil wellholes,providing a technical guidance and valuable reference experience for the efficient development and stable production of shale oil.

关 键 词：页岩油 高气油比 水平井 井筒 结垢 碳酸亚铁 阻垢剂 井下点滴加药器 

分 类 号：TE39[石油与天然气工程—油气田开发工程] TE349