大邑区块新型低密度水泥浆体系研究

A NEW LOW-DENSITY SLURRY SYSTEM FOR DAYI BLOCK

大邑区块储层为裂缝型气层,地层压力低,使用正常密度水泥浆体系固井易导致地层漏失、垮塌等问题。基于此,设计了一套低密度水泥浆体系,对使用减轻材料漂珠的适宜目数及辅助材料、外加剂体系进行了研究。确定了该水泥浆体系的最佳配方:JHG+29%PZ+18%WG+1.5%降失水剂+0.5%减阻剂+2%膨胀剂+1%增塑剂+58%H2O。实验结果表明,该体系具有稳定性良好,API失水量低,稠化时间可调,抗压强度高,流变性好等特点,并以该方案为基础在大邑区块的固井作业中应用取得了较好效果。

Most reservoirs in Dayi block are fractured gas ones with low pressure. To use a slurry system with normal density during cementing may easily cause lost circulation and collapse.So, a new low-density slurry system was developed. The suitable mesh of hollow microsphere,auxiliary material and admixture of the system were also studied. After that, an optimal formula was obtained: JHG + 29% PZ +18% WG + 1.5% filtrate reducer + 0.5% drag reducer + 2% expanding agent + 1% plasticizer + 58% H2 O. The experimental results show that this system is characterized by good stability, lower API fluid loss, adjustable thickening time, high compression strength, and good rheology. Better result has been achieved during cementing of Dayi block after adopting this formula.