川深1井超高温高压尾管固井技术

Ultra-High Temperature and High Pressure Liner Cementing Technology in Well Chuanshen 1

针对川深1井四开井段超高温高压地层尾管固井长效密封的需求,通过增大硅粉加量和合理匹配硅粉粒径抑制水泥石强度衰退,优选高温苯丙胶乳、纳米液硅等改善水泥浆的防气窜能力、力学性能、稳定性等,设计了适用于超高温高压地层的高密度防气窜水泥浆。其性能为:密度2.05kg/L,防气窜系数SPN值小于0.43,气窜模拟未见气窜现象发生;水泥石在180℃下养护14d抗压强度达到了41MPa,未见强度衰退现象;水泥石气测渗透率0.0081mD,单轴弹性模量为7.54GPa。川深1井四开井段采用高密度防气窜水泥浆,并采取“替净”、“压稳”和“封严”等固井技术措施,有效封隔了高压气层,为后期作业提供了良好的井筒环境。这表明,超高温高压地层通过优选合适的水泥浆,并采取相应的技术措施,可以解决超高温高压地层的固井技术难点,提高固井质量。

The Well Chuanshen-1 encountered an ultra-high temperature and high pressure(ultra-HTHP)formation in the fourth drilling section.In order to ensure the long-term sealing of setting cement in this section,it is preferable to restrain the strength deterioration of setting cement by increasing the silicon powder dosage and by reasonably matching the particle sizes of silicon powder.In addition,the high-temperature styrene-acrylic latex and the nano-liquid silicon have been selected to improve the anti-gas channeling ability,mechanical properties and stability of cement slurry.For this purpose,a high-density anti-gas channeling cement slurry suitable for ultra-HTHP formation was designed,with a density of 2.05 kg/L and an anti-gas channeling coefficient SPN lower than 0.43.In this case,no gas channeling was observed in gas channeling simulation;the compressive strength of set cement reached 41 MPa at 180°C for 14 d,and no strength deterioration of cement stone was found;the gas measurement permeability of the set cement was 0.008 1 mD,and the uniaxial elastic modulus of set cement was 7.54 GPa.The high-density anti-gas channeling cement slurry was applied in the fourth drilling section of Well Chuanshen-1,and the cementing measures such as"thoroughly displacement","stable well killing"and"sealing securely"were adopted,which effectively isolated the high-pressure gas layers and provided a good wellbore environment for the successive operations.This process proved that the ultra-high temperature and high pressure formation could be smoothly cemented by using the suitable cement slurry and taking proper technical measures,and an in following those procedures,it could be possible in the future to assure high cementing quality.