Anti-channeling High Density Cement Slurry Used in Cementing Well Hongbei-1

The well Hongbei-1 is a well with the frst class well control risk drilled in the Qinghai oilfeld. It is also a well with the highest formation pressure drilled in that oilfeld. A high density (2.4 g/cm³) anti-channeling cement slurry was developed to cope with the cement slurry channeling. Hematite, a weighting material that needs less water in formulating drilling fluid, was selected to weight the cement slurry. To enhance the stability of the cement slurry, an ultra-fne amorphous particles, CEA-1, was used as extender. CEA-1 has the ability to adsorb large amount of free water and has a higher reactivity. An anti-channeling agent, FLOK-2, was developed by mixing a latex fber as the primary component, with CaCl₂ and K₂O as the secondary components. A high performance friction reducer, FS-13L, was developed by reaction between carboxylic acid as the primary raw material, and sodium sulfte as the secondary raw material. Laboratory experiment has shown that the SPN of the cement slurry was<3. When temperature changed by±5℃, the thickening time of the cement slurry changed by less than 44 min. When the density of the cement slurry changed by±0.05 g/cm³, the flow index of the cement slurry varied between 0.71 and 0.59, and the consistency factor varied between 1.06 mPa·sⁿ and 3.14 mPa·sⁿ. A flushing spacer compatible with the drilling fluid used was also developed. The composition of the spacer is:water+320% hematite powder+35%OCW-1L (flushing agent)+10%CEA-1+4%spacer agent. Field application has shown that this cement slurry had good stability and anti-channeling performance. When used in combination with assorted technical measures, the quality of the cementing job can be enhanced, and operation safety ensured.