摘要
同普通深探井相比,四川盆地及盆地周缘超深/特深探井酸压改造面临井深更深、温度和压力更高、流体和岩性更复杂的工作环境,施工摩阻偏大、排量偏小、规模偏小、酸液有效作用距离偏短,改造效果较差,工具可靠性差、改造施工一次成功率低、安全保障难度高,投入大、产量不理想,勘探进展较为缓慢。为此,应用国内外油气行业、制造业的最新研究成果,结合自身实际和经验教训开展技术攻关,用新型大通径高强度气密封入井管柱替代传统管柱,降阻提排量;用可同时激发的双向双金属密封替代双向单金属密封,实现密封能力可检验和长期保持稳定,以提高井口控制能力;用双向锚定胀封封隔器取代底端锚定旋转加压坐封封隔器,以降低酸压期间管柱伸缩引起胶筒移动和密封失效的概率,多套减振器串联可以降低爆轰力的不利影响;用“四阀一封”取代“两阀一封”备份阀件并串联使用,以提升可靠性;研发适应温度≥220℃、压力≥180 MPa的缓蚀、缓速工作液;将只相信两联作的理念改为两联作和三联作并重,形成了酸压工艺优选方法。现场应用进展顺利,安全保障能力、改造规模及压裂效果、施工一次成功率均显著提升,可为同类井酸压改造提供技术借鉴。
Compared with that of ordinary deep exploratory wells,the acid fracturing of ultra/extra-deep wells in the Sichuan Basin and its periphery faces the working environments featuring deeper wells,higher temperature and pressure,and more complicated fluid and lithology,and it has the problems of large operating friction,low flow rate,small scale,short effective distance of acid solution,poor fracturing result,unreliable tools,low success rate of the first operation execution,difficult security guarantee,expensive investment,and unsatisfactory yield.Therefore,the exploration progress of such wells is slow.By applying the latest achievements of the oil and gas industry and manufacturing industry in China and abroad,the technical research was conducted based on actual experiences and lessons,and the new large-diameter and high-strength air-tight seal pipe string was used to replace the traditional pipe string to reduce the friction and increase the flow rate.The bi-directional bimetal seal which could be motivated simultaneously was used to replace the bi-directional single-metal seal to test the sealability and maintain the long-term stability,so as to increase the wellhead control capacity;and the bi-directional anchored expansion packer was used to replace the bottom-anchored rotary pressure setting packer,so as to reduce the probability of cylinder movement and seal failure caused by pipe string expansion during acid fracturing.Multiple sets of shock absorbers were connected in series to reduce the adverse effects of detonation force,and the“four-valve-one-packer”method was adopted to replace the“two-valve-one-packer”method.In addition,the backup valves were connected in series to improve reliability,and the corrosion-inhibiting and velocity-retarding working fluid suitable for temperature of≥220°C and pressure of≥180 MPa was developed.Equal emphasis was placed on simultaneous two-step operation and simultaneous three-step operation instead of the traditional emphasis on simultaneous two-step operation,and thus the optimum selection method of the acid fracturing process was established.The field application was progressing smoothly,and the safety guarantee ability,fracturing scale,fracturing effect,and success rate of the first operation execution were significantly improved,providing a reference for acid fracturing of similar wells.
作者
李荷婷
代俊清
李真祥
LI Heting;DAI Junqing;LI Zhenxiang(Science and Technology Department,Sinopec Southwest Oil&Gas Company,Chengdu,Sichuan,610041,China;Sinopec Exploration Company,Chengdu,Sichuan,610041,China)
出处
《石油钻探技术》
CAS
CSCD
北大核心
2024年第2期202-210,共9页
Petroleum Drilling Techniques
关键词
探井
超深层
特深层
酸化压裂
储层改造
工艺优选
四川盆地
exploratory wells
ultra-deep reservoir
extra-deep reservoir
acid fracturing
reservoir stimulation
process optimization
Sichuan Basin
