多功能水泥外加剂在BZ25-1油田固井中的应用

配制一种满足现场固井技术要求的水泥浆,往往需要四五种外加剂来调节,而不同的外加剂混在一起会互相影响,产生相容性的问题,给现场配制水泥浆和固井作业带来很多困难.研究开发出了多功能油井水泥外加剂.该外加剂是一种合成共聚物,它含有大量的对水泥颗粒具有分散和吸附作用的基团,用该外加剂配制出的水泥浆性能稳定,具有良好的流变性和稳定性,游离液的控制能力强.多功能油井水泥外加剂具有降失水、分散减阻和自调凝功能,抗盐、抗钻井液污染.经现场应用表明,用多功能外加剂配制出的水泥浆过渡时间短,强度发展快,具有较强的防窜能力,配合单级双封工艺,可用于长封固井段固井;该体系具有低失水、低游离液、抗海水和抗钻井液污染的能力,应用简便,性能稳定,适应能力强.在BZ25-1油田19口常规定向井的固井中,经过CBL检测,所有油层封固井段的声幅值小于10%,固井一次优质率为100%.

Application of a multi-functional cement additive in BZ25-1 oilfield

To prepare cement slurry that satisfy requirements of field using, four or five cement additives are needed to condition the slurry properties. Whereas when different additives are blended together, they interact with each other, sometimes results in the potential problem of compatibility, leading difficulties in preparing cement slurry onsite and subsequent cementing job. A multifunctional oil well cement additive was developed. The additive is a copolymer with large numbers of functional groups on its structure backbone, of which some are to disperse the cement particles and some are to absorb the cement particles. The cement slurry with the additive in has stable property, good rheology property and strong free water control ability. In addition, the agent possesses characteristics such as filtration control, dispersion and auto-thickening conditioning property, and resistance to contamination by salt and mud. Field experience showed that the slurry prepared with this additive behaves short transit thickening time, fast strength development, effective anti-gas channeling properties. Incorporated with single stage- double isolation cementing technology, it meets requirements of long section cementing. The filtrate is low, the free water is less. CBL data of 19 conventional directional drilling wells in BZ25-1 Oilfield illustrated that all the amplitude values were less than 10%, and the one-trip high quality rate was 100%.