Research and application of hydraulic centralizer for horizontal well cementing

Casing tends to be put near the lower wellbore when cementing horizontal wells, in other words, the centralized degree is poor, so the cement thickness is unequal around the casing, resulting in poor cementing quality, and it restricts the advantages of horizontal wells severely. Centralizer is usually used to improve the casing centralized degree in the field, but conventional centralizers has some problems, such as large diameter, difficulties in tripping into the hole, and breaking wellbore. So the hydraulic centralizer for horizontal well cementing was developed. It has some advantages, such as small original diameter, safety in tripping into the hole and large diameter after expansion. It can improve the centralized degree significantly and make burbling effect in cementing. The quality of cementing is improved greatly with the hydraulic centralizer. The application of centralizer in fields is simple, and does not affect cementing process. The tool has been used in many wells in Shengli Oilfield with significant effect.