普光气田固井质量评价难点与对策

普光气田高含硫化氢,气井固井水泥浆体系多样化。当水泥浆凝固时间较短时,采用声波变密度测井（CBL/VDL）的方法来检验固井的胶结质量时,由于水泥浆尚未完全胶结,水泥环与套管、地层的声耦合很差,使得套管波幅度大大升高,造成第一、第二界面的胶结质量很差的误判,水泥浆凝固时间过长同样会造成胶结质量差的错误判断。为此,提出在应用声波变密度测井资料进行固井质量评价时,应充分考虑测井时间、地层岩性、水泥环隙、气侵等因素的影响,同时结合川东北地区固井质量评价规范,作出正确的质量评价,使声波变密度测井真正成为检验固井质量的有效手段。

Bottleneck points and corresponding measures for cementing evaluation in Puguang gas field

Due to the variety of cement slurry systems for H2S gas well cementing in the Puguang gas field, a false judgment is often obtained when using CBL/VDL (cement bond logging/variable density logging) to check the bond quality of cementing job with short set time slurry at interfaces I and II. The reason is that the cement has not been fully set, the poor acoustic coupling between the cement sheath, the casing and the formation will largely increase the amplitude of the casing wave. This paper recommends that the logging time, formation lithology, cement sheath clearance, gas influx, and other affecting factors should be taken into consideration when doing CBL/VDL cementing evaluation, meanwhile combining with the cementing quality evaluation standards for Northeast Sichuan basin, so as to make a correct cement quality evaluation.