提高水泥层间封隔能力的低密度弹性密封水泥浆性能评价

Performance Evaluation of Elastic Sealing Cement Slurry with Low Density for Improving the Sealing Capacity between Cement Layers

幸雪松 孙翀 许明标 王晓亮 杨晓榕 彭石峰

XING Xuesong SUN Chong XU Mingbiao WANG Xiaoliang YANG Xiaorong PENG Shifeng

在现有的固井水泥浆技术条件下，保障井筒完整性长期稳定面临挑战，尤其是常规低密度水泥浆，射孔后水泥石的完整性遭到严重破坏，造成密封失效，水泥石与套管及井壁间的胶结质量差，易发生窜槽等问题。针对上述问题，以环氧树脂和酸酐类固化剂为原料制得弹性剂（RES-1），并用液体纤维提高水泥石的强度和韧性、纳米液体减轻剂改善水泥浆沉降稳定性。室内对低密度弹性密封水泥浆展开了综合性能评价。结果表明，RES-1可降低水泥石的弹性模量，提高水泥石的形变能力，最优加量为10%。低密度（1.5 g/cm3）弹性密封水泥浆体系具有良好的流变性，失水量小于50 mL，线性膨胀率达到0.45%，可有效抑制微环隙、微间隙的产生。低密度弹性密封水泥浆具有较好的致密性、柔韧性和弹性形变能力。与普通低密度水泥浆相比，其渗透率和弹性模量分别降低了69.5%和78.4%，抗压强度和抗折强度分别提高了61%和87.9%。低密度弹性密封水泥浆可以有效提高水泥环的长效封隔能力，改善固井质量。

Under the existing cementing slurry technology，ensuring the long-term stability of wellbore integrity is facing challenges，especially the conventional slurry with low density. After perforation，the integrity of cement stone is seriously damaged，resulting in sealing failure，poor cementing quality between cement stone and casing or well wall，and channeling is easy to occur. In view of the above problems，the elastic agent（RES-1）was prepared by using epoxy resin and anhydride curing agent as raw materials，the liquid fiber was used to increase the strength and toughness of cement paste，and the nano liquid lightening agent was used to improve the settlement stability of cement slurry. The comprehensive performance evaluation of elastic sealing cement slurry with low density was carried out. The results showed that RES-1 could reduce the elastic modulus and improve the deformation capacity of cement paste. The optimum dosage was 10%. The elastic sealing cement slurry system with low density （1.5 g/cm3）had good rheology. The water loss was less than 50 mL and the linear expansion rate reached 0.45%，which could effectively inhibit the generation of micro annulus and micro gap. The elastic sealing cement slurry with low density had good compactness，flexibility and elastic deformation ability. Compared with ordinary cement slurry with low density，its permeability and elastic modulus were reduced by 69.5% and 78.4%，and its compressive strength and flexural strength were increased by 61% and 87.9% respectively. The elastic sealing cement slurry with low density could effectively increase the long-term sealing capacity of cement sheath and improve cementing quality.

10.19346/j.cnki.1000-4092.2022.02.006