早强超低密度水泥浆在致密油井云探1井的应用

Application of Early-strength Ultra-low Density Cement Slurry in Tight Oil Well Yuntan1

针对云探1井Φ244.5 mm套管低压、易漏失地层的固井难题,通过优选高强空心玻璃微珠减轻材料,与超细水泥、微硅粉进行颗粒级配,研究出一套早强超低密度水泥浆配方。水泥浆密度1.20~1.25 g·cm^(-3)之间可调,失水量小于50 mL,游离液量为零,沉降稳定性密度差小于0.02 g·cm^(-3),稠化时间可调,49℃下48 h水泥石抗压强度达到20 MPa。配合高效冲洗型隔离液的应用,冲刷井壁和套管,使原本亲油相变成亲水相,提高了顶替效率。通过现场应用,固井过程中没有发生漏失,水泥浆一次性返出地面,固井质量合格率为99.5%,为低压、易漏失地层固井提供了技术支撑。

For well Yuntan 1,in order to solve the cementing problem ofΦ244.5 mm casing in low-pressure and leaky formation,a set of early strength ultra-low density cement slurry formula was developed by selecting high-strength hollow glass beads to reduce the material,and particle grading with ultra-fine cement and micro silica powder.The density of cement slurry is adjustable between 1.20~1.25 g·cm^(-3),the water loss is less than 50 mL,the amount of free liquid is zero,the density difference of settlement stability is less than 0.02 g·cm^(-3),the thickening time is adjustable,and the compressive strength of cement paste reaches 20 MPa after 48 h at 49℃.Combined with the application of high-efficiency flushing isolation fluid,it can wash the well wall and casing,change the original lipophilic phase into hydrophilic phase to improve the displacement efficiency.Through field application,there was no leakage during cementing,the cement slurry returned to the ground at one time,and the qualified rate of cementing quality was 99.5%.The formula can provide technical support for cementing in low-pressure and leaky formations.