摘要
在“漏溢同存”复杂井筒建立有效段塞以屏障阻隔油气上移通道,能为堵漏压井、起下管柱等钻井、完井作业提供安全时间。基于水化胶凝和树脂交联固化理论,设计一种利用地层温度和流体碱度激发硬化反应的可固化凝胶段塞工作液体系,并对其性能进行研究。研究结果表明:(1)可固化凝胶段塞工作液的流变参数设计合理,具有良好的剪切稀释性能、可泵送性能及沉降稳定性能。(2)该工作液的适用密度范围1.4~2.0 g/cm~3,抗温可达140℃,调整激活剂的用量可实现稠化时间大于3.0 h,满足泵注、顶替等施工要求。(3)该工作液固化段塞的孔隙度为2.1%~3.5%,气测渗透率为0.0032~0.0045 mD,在?177.8 mm金属管内承压达1.5 MPa/m,表明固化后的段塞致密、与金属内壁胶结紧密,因而封隔气窜能力强。(4)固化段塞的抗压强度,与该工作液的恒温养护时间及体系密度呈正相关,在温度不超过140℃时,抗压强度随温度的升高而增加;当温度超过140℃后,抗压强度降低,分析其原因为高温下形成的微裂缝和微孔隙所致。(5)初步现场试验表明,该工作液体系固化后形成的凝胶段塞,有效地降低了油气峰值、上窜高度及上窜速度,具备良好的油气封隔能力。
Establishing an effective slug in a complex wellbore with both leakage and overflow to block the upward movement of oil and gas can provide safe time for drilling and completion operations such as plugging, well killing, and trip. Based on the crosslinking and curing theory of hydration gel and resin, a curable gel slug working fluid system was designed, which utilizes formation temperature and fluid alkalinity to stimulate the hardening reaction, and its properties were studied. Results show that the curable gel slug working fluid system is designed with proper rheological parameters, exhibiting good performance in shear dilution, pumpability, and stability of sedimentation. The working fluid system is applicable to a density ranging from 1.4 g/cm3 to 2.0 g/cm~3, and a temperature up to 140℃. The thickening time can be more than 3 hours by adjusting the activator dosage, which meets the requirements of pump injection and replacement. The curable gel slug has the porosity of 2.1%~3.5%, the gas logging permeability of 0.0 032~0.0 045 mD,and the bearing pressure up to 1.5 MPa/m in ?177.8 mm metal tube, indicating that the cured gel slug is compact and tightly bonded with the inner wall of metal to efficiently seal off gas channeling. The compressive strength of the slug is positively correlated with the constant temperature curing time and density of the working fluid. Within the temperature of 140°C, the compressive strength increases with temperature. When the temperature exceeds 140°C, the compressive strength decreases due to the micro-fractures and micro-pores formed at high temperature. Preliminary field test demonstrates that the gel slug formed by cured working fluid system effectively reduces the peak value of oil and gas, and the height and speed of upward channeling, recording a good blocking ability.
作者
向朝纲
贺彬
李华坤
陈鑫
高利华
Xiang Chaogang;He Bin;Li Huakun;Chen Xin;Gao Lihua(Drilling&Production Technology Research Institute,CNPC Chuanqing Drilling Engineering Company Limited,Guanghan,Sichuan 618300,China;International Ltd.,CNPC Chuanqing Drilling Engineering Company Limited,Chengdu,Sichuan 610000,China)
出处
《天然气勘探与开发》
2022年第4期70-77,共8页
Natural Gas Exploration and Development
关键词
凝胶段塞
固化
抗高温
窄安全密度窗口
油气阻隔
Gel slug
Curing
High temperature resistance
Narrow safe density window
Oil and gas blocking
