深井无固相压胶塞隔离液的研究与应用

柴达木盆地深井固井作业中,由于某些钻井液性能不达标或胶塞封闭不严致使部分水泥浆与顶替钻井液发生絮凝反应等原因,导致固井质量电测仪器下不到井底。为此,研制了无固相压胶塞隔离液。通过压胶塞隔离液的抗水泥浆污染性能、高温稳定性能和沉降稳定性能等评价实验,优选出深井完井压胶塞隔离液配方。现场应用结果表明,在胶塞和顶替钻井液之间的300~500 m的无固相隔离液段,可有效阻止套管内残留水泥浆与钻井液发生絮凝反应,并减缓固相颗粒的沉降堆积,保证电测仪器顺利下井。使用无固相压胶塞隔离液的37口深井,完井固井质量电测一次成功率达到了100%,有效缩短了完井作业施工周期。

Research and application of solid-free rubber plug press spacer fluid in deep wells

In cementing jobs in deep wells in Qaidam Basin, due to some substandard drilling fluid properties or poor sealing of rubber plug, some cement slurry reacted with displacing drilling fluid and got flocculated, which caused cementing problems and the electric log could not be lowed to hole bottom. For this reason, the solid-free rubber plug pressed spacer fluid was developed. By evaluating experiments on the performances of resistance to cement contamination, high temperature and subsidence stability of rubber plug pressed spacer fluid, the best formula of plug pressed spacer fluid was selected for deep well completions. Field application shows that the solid-free spacer fluid of 300~500 m between the plug and displacing drilling fluid can effectively prevent the remaining cement in the casing from being flocculated with drilling fluid and also slow down settling and piling up of solid particles. In 37 deep wells where solid-free plug spacer fluid was used, the one-time success rate of electric log for completion cementing quality was 100%, effectively shortening the period of completion operations.