溶洞-裂缝型复杂井堵漏新型触变水泥体系研究

为更好地解决溶洞-裂缝型复杂井井漏问题,以延迟型触变剂SCA和促强型堵漏剂SM为主要外掺料,开发出新型触变水泥体系,并对体系的触变性能、流动性能、失水量、稠化时间和抗压强度等进行了室内测试。试验结果表明,该体系的延迟触变时间为300 s,300 s后最大剪切应力增长很快,表现出良好的触变性能;流动性能好,API失水量小于150 mL/30 min;体系的水泥石不仅具有较高的早期强度而且24 h抗压强度接近20 MPa,水泥石体积也具有微膨胀性。该研究为溶洞-裂缝型复杂井堵漏提供了一种高效、简单、经济的新方法。

Investigation on new thixotropic cement system for lost circulation control in vug-fracture type complex wells

To better resolve the problem of lost circulation in vug-fractures type complex wells, a new type of thixotropic cement was prepared mainly depending on the combination of a delayed thixotropic agent SCA and a strength-enhancing lost circulation material SM. The thixotropic property, flow property, fluid loss, thickening time and compressive strength of the system were carried out by in-house tests. The test results demonstrate that the slurry system has favorable thixotropic property, which is manifested on its delayed thixotropic time for 300 seconds and afterwards the shear stress rapidly increases. Meanwhile, the system shows good flow property, satisfactory API water loss being less than 150 mL/30 rain. The set cement not only shows high early compressive strength which is near to 20 MPa after cured for 24 h, but also has fine certain volume expansion. The research offers a new high-efficiency, facile and economical approach for lost circulation control in rug-fracture type complex wells.