固井用热固性树脂–镁氧水泥复合材料研究

Study of a Thermosetting Resin-Magnesia Cement Composite for Cementing

常规油井水泥石脆性大、体积收缩幅度大,使水泥环胶结质量不高且在规模化压裂及生产时易破坏,从而导致油气井环空带压,为此优选了热固性树脂、镁氧水泥骨架材料和固化剂,研制了调凝剂,制备了热固性树脂-镁氧水泥复合材料.室内试验表明,该复合材料密度1.1~1.8 g/cm3,24 h抗压强度大于14.0 MPa,弹性模量2~4 GPa,能够承受70 MPa应力疲劳破坏,具有比油井水泥更好的抗破坏密封能力.现场试验结果表明,热固性树脂-镁氧水泥复合材料现场混配方便,与常规油井水泥固井设备和工艺完全兼容,具有良好的现场适用性和封固效果.研究认为,该复合材料不仅解决了油井水泥存在的问题,还可在油气层封堵、带压井治理及油气废弃井封井等方面替代油井水泥,为油气井的密封完整性提供技术保障.

Due to the fact that a set cement is characterized by high brittleness and large volume shrinkage after cementing,and also that the cement sheath is easily damaged during large-scale fracturing and production process,resulting in poor bonding quality and causing sustained casing pressure(SCP),etc.,research on the composite material,i.e.thermosetting resin-magnesia cement was conducted.The thermosetting resin,magnesia cement skeleton material and curing agent were optimized,and a team developed coagulator and composite material of thermosetting resin and magnesia cement.An indoor test showed that the composite material had the density of 1.1–1.8 g/cm3,compressive strength of more than 14.0 MPa after 24 hours,and elastic modulus of 2–4 GPa,which can withstand stress fatigue damage of 70 MPa,and present better sealing and damage resistance than oil well cement.The field test results indicated that the composite material of thermosetting resinmagnesia cement was convenient for mixing at well site.Further,is was fully compatible with conventional well cementing equipment and process.It has with good field applicability and sealing effect.The research suggested that the composite material could completely solve the problems of oil well cement,even substitute the well cement for sealing the oil and gas layer,combined with SCP wells treatment and oil and gas wells abandonment,etc.,so as to ensure the sealing integrity of oil and gas wells.